Climate Science Glossary

Term Lookup

Enter a term in the search box to find its definition.


Use the controls in the far right panel to increase or decrease the number of terms automatically displayed (or to completely turn that feature off).

Term Lookup


All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

Home Arguments Software Resources Comments The Consensus Project Translations About Support

Twitter Facebook YouTube Pinterest MeWe

RSS Posts RSS Comments Email Subscribe

Climate's changed before
It's the sun
It's not bad
There is no consensus
It's cooling
Models are unreliable
Temp record is unreliable
Animals and plants can adapt
It hasn't warmed since 1998
Antarctica is gaining ice
View All Arguments...

New? Register here
Forgot your password?

Latest Posts


Search Tips

Comment Search Results

Search for albedo

Comments matching the search albedo:

    More than 100 comments found. Only the most recent 100 have been displayed.

  • It's albedo

    blaisct at 07:22 AM on 9 December, 2021

    The data presented earlier in this thread has been updated in document Earth's Albedo 1998–2017 as Measured From Earthshine


    albedo data from earth shine and CERES

    Figure 3
    “Earthshine annual mean albedo anomalies 1998–2017 expressed as reflected flux in . The error bars are shown as a shaded gray area and the dashed black line shows a linear fit to the Earthshine annual reflected energy flux anomalies. The CERES annual albedo anomalies 2001–2019, also expressed in , are shown in blue. A linear fit to the CERES data (2001–2019) is shown with a blue dashed line. Average error bars for CERES measurements are of the order of 0.2 .”

    This new data shows a good agreement between earth shine data and CERES satellite data one can also add the earth’s temperature for this time to this graph and fined good agreement with the albedo (+0.4'C or 0.8 W/m^2 in 20 years). The implication is that the earths albedo change can account for all the temperature rise over this time period. The document suggest that this albedo change was possibly due to reduced cloud cover. Leaving the question what caused the reduced cloud cover.


  • CO2 lags temperature

    MA Rodger at 01:53 AM on 13 November, 2021

    Yoshi @635,

    I fear you misinterpret the 90% figure. As described by Skakun et al (2012) (& discussed in this SkS post), the 90% is not the percentage of warming coming out of an ice age that is caused by CO2. It is the percentage when increases in CO2 occur prior to increases in global temperature.

    The actual post-ice-age warming resulting from increased CO2 is a portion of the GHG warming (which also includes methane). The GHG warming is given as 37% of the total in this CarbonBrief explainer. (The remainder is given as 50% ice albedo & 13% dust & aerosols.) The actual CO2 forcing is about 2.5Wm^-2.

    The cooling of the world that leads to a glacial maximum is much slower than the warming of the world that leads to an interglacial. The cooling begins with increased albedo in high northern latitudes as they lose sunlight through the orbital wobbles.

    The warming is quicker because it takes less time to melt down an ice sheet than it does to build it up. As with the warming, CO2 reacts to this cooling and increases the effect.

  • It's the sun

    cph at 21:57 PM on 11 November, 2021


    Diagram showing the monthly fluctuations in total global cloud cover since July 1983. During the observation period, the total amount of clouds fluctuated from about 69 percent in 1987 to about 64 percent in 2000. The annual variation in cloud cover follows the annual variation in atmospheric water vapor content, which presumably reflects the asymmetrical distribution of land and ocean on planet Earth.


    Within the still short period of satellite cloud cover observations, global cloud cover reached a maximum of about 69 percent in 1987 and a minimum of about 64 percent in 2000 (see diagram above), a decrease of about 5 percent. This decrease corresponds roughly to a net change in radiation of around 0.9 W / m2 within a period of only 13 years, which can be compared with the total net change estimated by the IPCC 2007 report from 1750 to 2006 of 1.6 W / m2 for all climate drivers including greenhouse gas emissions from fossil fuel burning(cooresponds to your mentioned 2,5-3W/m² in 2021). These observations leave little doubt that cloud cover variations can have a profound impact on global climate and meteorology on almost every time scale considered.

    The total reflectance (albedo) of the planet earth is about 30 percent, which means that about 30 percent of the incident short-wave solar radiation is reflected back into space. If all the clouds were removed, the global albedo would drop to around 15 percent and the short-wave energy available to warm the planet's surface would increase from 239 W / m2 to 288 W / m2 (Hartmann 1994). However, long-wave radiation would also be affected, which emits 266 W / m2 into space compared to the current 234 W / m2 (Hartmann 1994). The net effect of removing all clouds would therefore still be an increase in net radiation of around 17 W / m2. So the global cloud cover has a significant overall cooling effect on the planet, although the net effect of high and low clouds is opposite.

    HK: - "but also through its warming effect through its strong greenhouse effect, which is the most important of all positive (reinforcing) feedbacks on a global level."

    Wild, M., Hakuba, M.Z., Folini, D. et al. The cloud-free global energy balance and inferred cloud radiative effects: an assessment based on direct observations and climate models. Clim Dyn 52, 4787-4812 (2019).
    According to the current status, the net radiation effect of clouds is -19W / m² (Wild 2019) and corresponds very well with + 0.9W / m² per 5% less cloud cover.


    High levels of global cloud cover are associated with low global temperatures, demonstrating the cooling effect of clouds.                        A simple linear fit model suggests that a 1 percent increase in global cloud cover corresponds to a global temperature decrease                        of about 0.07 ° C.

  • It's the sun

    HK at 06:44 AM on 10 November, 2021

    My point in #1292 was that the 0.5 W/m2 of forcing from clouds and snow/ice is small compared to the overall net forcing over the last 150 years or so and that the albedo change brought up by you is at least partly a direct consequence of the warming, i.e., one of the positive feedbacks.

    However, I will admit that clouds and humidity are complex and can be influenced by other factors in addition to the direct result of man-made greenhouse gases. Desertification and deforestation in general and especially cutting down tropical rainforests can have a profound impact on the local hydrological cycle, changing humidity, cloud cover, rainfall and run-off and thus have an impact on the local temperature as well. So yes, man-made climate change isn't only about the greenhouse effect and the warming caused by it, but it's definitely the most important part of it on a global scale.
    It's also worth noting that even if the relative humidity seems to have decreased somewhat for the reasons explained here, the absolute or specific humidity has in fact increased, just as expected in a warming world.

    Specific humidity


    Water has an impact on the temperature not only via its removal of latent heat through evaporation – which has a local cooling impact – but also through its warming impact via its strong greenhouse effect, which is the most important of all the positive (amplifying) feedbacks on a global scale.

  • It's the sun

    cph at 22:01 PM on 9 November, 2021

    HK@1292 - "BTW, if clouds and snow/ice changed by themselves and not as a feedback to warming caused by GHGs, we wouldn't get a cooling stratosphere..."

    --- I did not understand your last sentence. I am of the opinion that, for example, a changed cloud albedo cannot be explained by a rise in temperature alone. Changes and anomalies in global mean cloud cover can also be caused by fewer (sulfate) aerosols or expanding deserts (dry regions become drier).

    Timeseries for evapotranspiration (top), precipitation (second from top), discharge (second from bottom) and change in ground water storage (bottom) over 2003-19.

    Evaporation increases by + 2.3 mm / year, which is not fully compensated for by increased precipitation of + 1 mm / year. A decreasing runoff through the rivers of -1.01 mm / year and a falling groundwater level of -0.75 mm / year quantify the drainage of the continents. This drainage (through drained bogs, wetlands, groundwater, aquifers, canalization of rivers and a constantly growing sealing of urban areas) is just as man-made as the CO² emissions, rising temperatures and the resulting higher evaporation. Too little H²O in desert regions and the earth's atmosphere, which in summer extend through droughts up to the Arctic Circle, are a temperature driver. Too much CO² is just as warming as too little H²O. Less evapotranspiration -> less cloud albedo -> higher incoming radiation energy and record temperatures on the earth's surface -> even faster drying out with even higher temperatures - imho, similar to the ice-snow albedo, form a vicious circle.

    The authors estimate a "statistically significant" increase in evapotranspiration of around 10% above the long-term mean (corresponds to a temperature increase over land areas of ~ + 1.44 ° C). During the same period, precipitation only increased by 3% and global river runoff decreased by 6%.


    What is noticeable here is a simultaneous decrease in relative humidity and cloudiness, which certainly correlates with a general increase in the number of hours of sunshine.

    time series sunshine hours germany 1951-2020


    Global time series of annual average relative humidity for the land (green line), ocean (blue) and global average (dark blue), relative to 1981-2010.

  • SkS Analogy 25 - Emissions vs Accumulation

    cph at 08:33 AM on 9 November, 2021

    michael sweet@19 - "It appears that large scale irrigation lowers the temperature a little. This has been known for a long time..."

    -— What you call a wild plan - I call it water cooling. It is much more efficient than air cooling and is generally described in climate science as the Bowen ratio. While it is ~ 0.1 over tropical oceans and rainforests, it reaches ~ 10 in deserts.

    Decreasing surface BR plays a major role in the surface energy budget. It is estimated that the cloud feedback may increase albedo by 0.13 and reduce Rnet by 25 W m−2 in summer over agricultural land.

    ms: - " The suggestion of piping enourmous volumes of water to the desert is absurd. / ...all available water is already used for irrigation and no additional water remains. "

    -— I suggested a water transfer without pipeline ! Absurd - is to think that you only have to turn on the tap to get water. / Perhaps in the Central Valley people should start thinking about using the water retention measures I described above. - In principle a simple, worldwide request to politics, agriculture, industry but also to private persons to build up extensive water reserves wherever & whenever possible in order to use them generously in plant growth, evaporation, clouds and "water cooling" during periods of drought in spring and summer.

  • It's the sun

    HK at 01:05 AM on 7 November, 2021

    "Explained by the cloud and snow / ice albedo that has decreased in the last few decades (0,5W/m² which is a lot)."


    The net forcing from the preindustrial period when counting both the positive forcing from the greenhouse gases and the negative forcing from man-made aerosols is now roughly 2.5–3 W/m².
    Changes in clouds and the snow/ice albedo are positive feedbacks amplifying that warming. The most important and fastest of those is the water vapour feedback which roughly doubles the initial warming.

    BTW, if clouds and snow/ice changed by themselves and not as a feedback to warming caused by GHGs, we wouldn't get a cooling stratosphere or more warming in winter than summer at high northern latitudes.

  • It's the sun

    cph at 00:09 AM on 7 November, 2021

    HK@1290 -

    "The only explanation making sense is that the Earth gives off less heat to space."

    --- Another additional explanation would be the fact, that the earth absorbs more short-wave solar energy from space, although the solar constant(1360,5W/m²) tends to decrease actually.

    Explained by the cloud and snow / ice albedo that has decreased in the last few decades (0,5W/m² which is a lot).


  • SkS Analogy 25 - Emissions vs Accumulation

    Jim Eager at 07:14 AM on 3 November, 2021

    Are you deliberately missing the point? It has nothing to do with the radiative forcing of H2O, it has to do with the fact that you can not directly increase the amount of water vapour in the atmosphere without first warming the atmosphere, otherwise the added H2O will simply condense out.

    Thought experiment: Remove all other greenhouse gasses from the atmosphere except water vapour. What will happen?

    The greenhouse effect will be reduced, cooling the surface and atmosphere. As a result the atmosphere will be able to hold less water vapour, so it, too, will be reduced by condensation and precipitation, thereby further reducing the greenhouse effect. As a result the atmosphere will be able to hold even less H2O. And so on. Pretty soon this will effect surface albedo as the precipitated water freezes into snow and ice, which will reflect more sunlight and reduce temperature still further.

    The point is you can not directly increase H2O, which means it can not be a driver of greenhouse warming, only contribute to it as a feedback.

    As for referring to Wikipedia as an authority on anything, you're joking, right?

  • SkS Analogy 25 - Emissions vs Accumulation

    Jim Eager at 01:13 AM on 3 November, 2021

    cph: "what do you think of H2O as the most strongest one"

    While H2O is by far the main greenhouse gas, it is condensible at normal Earth temperatures so it can only act as a feedback, not as a driver or forcing. Why? To increase the amount of water vapor in the atmosphere the atmosphere must first warm by some other means, either by an increase in incoming sunlight, a change in surface albedo, or by an increase in CO2 and/or CH4 in the atmosphere, neither of which are condensible at normal Earth temperatures.

    cph: "Cows and sheep livestock generate more greenhouse gases as measured in CO2 equivalents than the entire transportation sector."

    This is shear nonsenese perpetuated by strident vegans who have hijacked climate change to further their own agenda. See the sector graph MA Roger posted. One could commit the same slight of hand by combining portions of the mining, smelting, petrochemical, manufacturing, and construction sectors related to the tranport system into the transportation total. It is fundamentally dishonest to do that with livestock but not with other sectors, and it renders sector attribution meaningless.

  • It's albedo

    MA Rodger at 01:40 AM on 26 October, 2021

    I was reluctant to look into the values of Cloud Radiative Effect by location as up-thread the idea that added cloud & associated albedo came without added warming from water vapour seemed to be too difficult to accept by an insistent commenter and I wasn't sure how supportiive the result would turn out to be.

    However, Calisto et al (2014) does provide in its Fig 7 the positive and negative components of CRE by latitude for both Land & Ocean and they can be easilyare here adapted to show net CRE as in the following graphic (assuming the graphic is visible to others when I link to it). The net CRE by latitude is the gap between the bold red trace & the green/blue trace in the upper panels.

    Calisto et al (014) fig 7 adapted

  • It's albedo

    Bob Loblaw at 04:49 AM on 20 September, 2021

    I have no idea why the "hot link" problem occurs. When a simple click didn't get me to the graph, I tried copying the URL. When that worked, I thought I'd let others know.

    The sum of the trends isn't that far off 0:The balance is ET = Pr - Q - dS/dt, or 2.30 = 1.00 + 1.01 + 0.75 ==> 2.30 = 2.76, so only off by 0.46.

    (Pr, Q, and dS/dt are defined in the figure in MAR's comment.)

    I was able to download the Pascolini-Campbell et al paper through work. They do discuss the uncertainty in trends. On p 544, they say:

    "Propagated uncertainty in the trend is greatest for Pr (±0.41 mm yr−1 ), followed by Q (±0.32 mm yr −1), and smallest for dS/dt (±0.05 mm yr −1). This leads to a bounded ET trend estimate of 2.30 ± 0.52 mm yr−1 (determined by summing the square of the error in the trend of each component). The fractional uncertainty from Pr is 61%, 38% from Q and 1% from dS/dt. From this analysis it follows that the ET trend is positive and significant in light of the propagated error, and ranges from 1.78 mm yr−1 to 2.82 mm yr−1."

    This is getting off-topic for albedo, though.

  • It's albedo

    MA Rodger at 05:23 AM on 18 September, 2021

    The commenter @97 is no-longer a participant here but as this response to his comment @97 is albedo-stuff, I hope the moderators will allow it.

    ☻ Concerning the spectrum of reflected light in earthshine:- @97, the objection was to Woolf et al (2004) using an arbitrary ordinate scale on their Fig 1 (shown @96) rather than Wm^-2. Addressing this objection (although Woolf et al Fig 2 should have sufficed as it shows a roughly constant % albedo with wavelength), below is a graph of spectrum for wavelengths 0.25 to 6.5 microns (so into the UV) with a Wm^-2 ordinate scale. (Woolf et al above shows the spectrum 0.48 to 0.92 microns, so into the IR.)

    albedo spectrum

    ☻ Concerning Wild et al's -19Wm^-2 clear-sky radiation:- Indeed, as commented @97, it is "visa versa"  @96 as "cooling" was written in error and should have been "warming" from clear-sky relative to all-sky.

    Do note that the cooling from an AGW-induced decrease in albedo is greatly due to the reduction of tropical marine cloud. AR6 provides a better assessment of such cloud today that allows AR6 to state that "A net negative cloud feedback is very unlikely" with a potential range of -10Wm^-2ºC^-1 to +9.4Wm^-2ºC^-1 ['very likely' =1.67sd]. (Although half the range given in AR5, these remain broad confidence intervals.)

    Yet the -19Wm^-2 result from Wild et al (2019) was not misunderstood. The value is saying that the net energy balance under clear skys is -19Wm^-2 relative to the global average. (Note a coincidental -19Wm^-2 is also given by Wild et al for Land relative to Global.)
    It doesn't follow that a reduction of clear-sky conditions would result in a comenserate cooling of the planet (just as an increase in the land area of the planet would not be expected to increase planetary cooling). It is not so simple.
    Note what Wild et al consider their finding would be useful for:- "To better constrain (global climate models from CMIP5), we established new clear-sky reference climatologies." There is no mention of geo-engineering. (And note that if it were, the net planetary cooling would be -19Wm^-2 for the extra cloud and a further -19Wm^-2 for the loss of clear sky - this assuming a 50% global cloud fraction.) However, the impact of altering the global level of clear-sky conditions would depend entirely on the particulars of the alteration.
    Indeed, consider the cloud-effect in its totality. If the models take all the clouds out but keep everything the same, the GH-effect is diminished by about 15%. This would suggest increased cloud warms (and so does not cool,) a warming with a back-of-fag-packet global value of [33ºC GH-effect x 3.7Wm^-2/ºC x 15% =] +18Wm^-2. So +ve and not -ve. An interesting result.

    ☻ Finally, the mistake within the annotations of Fig3 of Pascolini-Campbell et al (2021) - It a trivial mistake (that the value of 2.3mm/yr in Fig3a should be 2.3mm/yr/yr and likewise elsewhere) as the mistake is quite evident. Simply look at the regression line. The graphed regression line rises from an anomaly of -18mm/yr in 2003.0 to +21mm/yr in 2020.0, so a rise of 39mm/yr over the 17-year period graphed = 2.3mm/yr/yr.

  • It's albedo

    coolmaster at 15:37 PM on 17 September, 2021


    MA Rodger: you state that "albedo is ... depends primarily on the wavelength of the light that hits the body/molecule." This is not correct. The reflected light is pretty-much independent of wavelength being no more than "bluish". The spectrum of reflected light is thus not significantly different from the spectrum of sunlight.

    coolmaster: I'm not sure if you know that e.g. plants are green (wavelength = ~ 550nm), a tomato red (~ 650nm) and blueberries (~ 450nm) blue when illuminated by sunlight with a full spectrum.

    Illuminated by a full spectrum (white), the objects appear to your eyes & brain in more or less monochrome light. So - many of the incident wavelengths are absorbed and only single colors are reflected.
    A snow surface is white and has a high albedo because all wavelengths are reflected in the range that is visible - nevertheless, snow absorbs very strongly in the long-wave range of IR radiation.

    What you describe as "bluish" is the Raleigh scatter.
    This has absolutely nothing to do with absorption, relative reflection and albedo.

    Your posted graph shows the spectral properties of the light emanating from the earth - and not the energy content of sunlight, that matters in an energy balance.
    Without having read the article - I guess you will hardly find the unit W / m², which is the important one for the radiation budget of the earth. So please don't mix it all up here. (MOD)

    MA Rodger: The TOA radiation balance under clear sky conditions averaged globally by Wild (2019) shows 19Wm^-2 more cooling than his all-sky average.
    coolmaster: No you are utterly wrong - it is vice versa.

    Or do you feel yourself cooler in sun under clear sky - and feel heat when a cloud covers the sun ????

    The radiation net effect of clouds and water vapor (CRE = -19W / m²) You still seem to confuse CRE with the atmospheric feedback of the clouds, which consists in the fact that with increasing temperature less cloud cover, changed lapse rate and optical depth are determined (+ 0.42Wm-2 ° C-1).    Earth - is - loosing - the clouds !

    MA Rodger: ☻ And to correct your bold assertions @94 / Your own derivation of a greatly different value of 344km^3/yr uses solely Fig 3a of the former paper which gives an annual rate of increase as 2.3mm/yr (it should actually be 2.3mm/yr/yr)???? and for the 16-year period the increase would be thus 5,500km^3/yr, in the circumstance not a significant difference from 7,000km^3/yr.

    coolmaster: 1500km³/yr is more than I suggested to retain.

    Can you give us just a reference or a page in the www. quote where the unit mm / yr / yr is used ???? You should then definitely get in touch with Ms. Madeleine Pascolini-Campbell and explain to her that she was mistaken by a factor of ~20.

    After all, her work and GRACE-FO are regarded worldwide as one of the most important findings of the last few years. So if you know better - go ahead ... Your pocket calculator with the built-in joker must have been very expensive.

  • It's albedo

    MA Rodger at 21:30 PM on 16 September, 2021

    coolmaster @94+,
    Trying to keep this on-topic for the thread (and I would have considered transferring this interchange on what is geo-engineering to another thread if it had a chance of being usefully continued), some Albedo issues which you raise.

    ☻ Firstly, within the deleted comment @95 (still visible to commenters), you state that "albedo is ... depends primarily on the wavelength of the light that hits the body/molecule." This is not correct. The reflected light is pretty-much independent of wavelength being no more than "bluish". The spectrum of reflected light is thus not significantly different from the spectrum of sunlight as Fig1 of Woolf et al (2002) demonstrates.

    Woolf et at (2002) Fig 1

    ☻ Your annotated graphics @71 are probably taking the simplisitic calculations a step-or-two too far.
    Want we can say from Wild (2014, 2019) is that Land Cloud albedo is shown as 19.7% with Land Surface albedo shown as 26.1%. Likewise Ocean Cloud albedo is given as 23.1% and Surface albedo as 8.1%.
    The TOA radiation balance under clear sky conditions averaged globally by Wild (2019) shows 19Wm^-2 more cooling than his all-sky average. Yet this result does not mean that cloud and its resulting albedo is overall a cooling influence. Cloud is well-known to cool if low and to warm if high and the latitude is also important. The usual climatological consideration is whether today cloud presents a positive or negative feedback to a warming world, the present understanding being that it is very likely positive, a position reinforced by recent work (eg Ceppi & Nowack (2021) [Abstract] (@94 you cite resumably IPCC AR6 with a similar finding.)

    We have up-thread shown very large increases in anthropogenic water 'use' on land and measured increases in evaporation over land. Thus to suggest an increase in evaopration over land would result in a higher cloud fraction and a strong cooling based solely on Wild's 19Wm^-2 is based on very shaky ground.

    And the following back-of-envelope calculations suggest there would not be cooling but warming.

    We see from Fig 2 Wild (2014) an all-sky Land Cloud albedo of 64Wm^-2. If cloud albedo were increased 1% that would pro rata present a global climate forcing of -0.19 Wm^-2 cloud albedo but with a loss of +0.05 Wm^-2 surface albedo. There is also reduced OLR cooling of +0.08 Wm^-2 pro rata suggested in Wild (2019) Fig14 and a water vapour forcing from the 1% increased humidity over land of roughly +0.12 Wm^-2. This would suggest a net warming from a 1% increase in Land evaporation of +0.06 Wm^-2, this a warming climate forcing larger than AGW.

    ☻ And to correct your bold assertions @94 concerning arithmetic. The 10% percent increase in land evaporation 2003-19 reported by Pascolini-Campbell et al (2021) multiplied by the 69,000/yr (+/-10%) land evaporation given by Abbott et al (2019) yields the 2003-19 increase of 7,000km^3/yr I present @93 (along with the references). The other values alongside which you object to are similarly derived.
    Your own derivation of a greatly different value of 344km^3/yr uses solely Fig 3a of the former paper which gives an annual rate of increase as 2.3mm/yr (it should actually be 2.3mm/yr/yr) and for the 16-year period the increase would be thus 5,500km^3/yr, in the circumstance not a significant difference from 7,000km^3/yr.

  • It's albedo

    coolmaster at 23:46 PM on 13 September, 2021


    "We know the planet is warming, and that human agency is causing it. What we cannot say yet is how climate change is affecting albedo, how it might be affected in the future, and what contribution to climate change - positive or negative - it may make."

    coolmaster: The albedo is relative ... and depends primarily on the wavelength of the light that hits the body/molecule. We should therefore always specify a wavelength range for the albedo. Otherwise, strictly speaking, the entire incoming spectrum of the sun ( UVC140nm up to Micro waves10cm) is decisive. This relativity to the albedo is particularly important for an element as widespread worldwide as H²O. I.e. ice and snow with an albedo of up to 0,9 in the visible range(380-780nm) has an albedo in the micro wave range of only < 0,1.

    Albedo of the earth ist 0,3 because absorbtion is 0,7(0,5 on the surface + 0,2 in the atmosphere) --> so the atmosphere has an albedo. Higher concentrations of GHG specially CO² is lowering the albedo of the atmosphere and is thus increasing temperature. We could always increase the albedo elsewhere: clouds, white color in the outdoor area or lighter field crops through foliar fertilization with light clays are just a few of the many possibilities.

    The temperature of the earth's surface is globally determined by the radiation balance, the radiation budget. This records the interaction between absorption and reflection as well as re-emission and scattering.
    But no matter which albedo you are looking at, whether short or long wave - a higher albedo can never cause a rise in temperature or energy. Conversely, every falling albedo increases temperatures or energy on earth.
    So I suggest that you update the last sentence of your basic rebuttal.

    @Moderation response: "last warning"

    In my last comment, which you would like to see in the slr section, the word albedo appears 3 times - the words clouds and cloud cover even more often. You should also warn others, who do exactly the same(i.e. MAR,BL).
    The inseparable connection between albedo - clouds - water and SLR was invented by an immovable mover (Aristotle's definition of God) ! not me !
    I don't want to discuss religion here, if only because I don't belong to any official religious community and because my religion is art. For me, climate science is a discipline, just like painting, sculpture, dance, music, and theater, etc.

    Nevertheless, I noticed that there once was a man who said he wanted to save the world. Among other things, because he supposedly could move over the water ...
    I also want to save the world ... and move (spiritually & physically) over the water.

    If you don't like my holistic, alternative climate protection strategy, which lowers sea level rise and earth temperatures - I can't change it, but I can't understand it either. In my opiniont it is the very last opportunity for you, your readers, commentators, your descendants, and the rest of creation to escape from climate hell (as long as anybody presents a much better, faster or cheaper concept.)

    That was my last warning to you...


  • It's albedo

    coolmaster at 10:47 AM on 13 September, 2021

    MA Rodger93:

    MAR: "Your proposed grand scheme seems to be assuming atmospheric water can increase by 0.001335M km^3 annualy, or a 10% annual increase."
    No - I never ever assumed, wrote or thought about that I plan or can increase atmospheric water by 1335km³ annualy.

    You are making a very similar mistake as Prof. Stefan Rahmstorf from PIK in Potsdam in response to my comment in another climate forum.

    Your mistake is probably that you have not read my posts with due attention, even though they are kept very simple and straightforward.
    An increase in atmospheric water by 10% / year would mean that, according to the CCF, earth temperatures rise by approx. 1.4 ° C per year. A state of the climate which means certain death for all life on earth.

    So you also completely misunderstood me.

    My climate protection strategy would like to take the volume of 3.7mm SLR(1335km³) from the global rivers discharge when their water levels are sufficient(&clean) or even specially in flood events after rain- !!! to store it in soil moisture and groundwater over the land mass.
    In principle a simple, seasonal storage of retained river water also to adapt to droughts and floods.

    In dry seasons, this water will be mainly evaporated from agriculture, but also the before mentioned “amunas” of the old inca culture and their water management are a perfect way to rewet forests & moors.

    This in turn ensures an increasing relative (and specific) humidity and additional cloud formation over land in a regional drought season.

    After an average of ~8.5 days in the atmosphere it will return – even with a relatively high probability – as precipitation over another land area. There will be a multiplier effect that increase together with soil moisture and evaporation rate (wet regions become wetter).

    As a result, the water cycle over the land areas is intensified by ~ 1-1,5% and thus the increasing size of the annual mean cloud cover over land areas leads to a higher albedo & CRE, which I estimate to be at least a cooling RF of ~ -0.2W/m² / year.
    A really cooling, additional radiative forcing, which, in my opinion, can more than compensate for the current annual radiative forcing caused by CO² .

    A holistic, functioning climate protection strategy,(stopping SLR AND global temperature rise & adaptation to droughts and floods) which works alternatively and independently of the reduction in CO² emissions, which only promises to stop the temperatures rise perhaps after ~ 2070 (if we as humanity can reduce emissions immediately – which I personally do not believe)

    In the latest IPCC report / WG1 Chapter, the positive feedback of the cloud cover on an atmosphere warmer by 1 ° C is given with +0.42W m-2 ° C-1.

    We are slowly but steadily losing not only areas of ice and snow albedo, but also the clouds albedo due to decreasing global mean cloud cover and higher lapse rate.
    The cooling CRE with ~-19W m-2 (chapter 7.2.1. in the same report) should decrease accordingly.

    The slower warming of the oceans means that there has not been enough moisture evaporated into – and then held in – the air above the oceans to keep pace with the rising temperatures over land. This means that the air is not as saturated as it was and – as the chart below shows – relative humidity has decreased, desertification is spreading rapidly mainly caused by human activities.
    Dryness is a temperature driver and cloud killer.

    That is why I (as an artist - not a climate scientist) think it's a good idea to create additional “artificial” clouds by additional artificial irrigation retained by river discharge from the superfluous water of the oceans.


    MAR: but the reported 10% increase in evaporation rate 2003-19 over land equates to some 7,000km^3/y while the reported 3% increase in rainfall equates to 3,300km^3/y and the decrease in direct discharge from land to ocean a further 3,000km^3/y.

    This suggests your grand scheme wouldn't make a ha'p'orth of difference. Evaporation over land is shown to have increased five-time the amount you propose yet AGW and SLR continued apace.

    coolmaster: ???

    360.57M km² ocean area * 3.7mm SLR = 1334.1km³ water = 8.93mm above the land area.

    149.43M km² land area * 2.3L / m² increasing evaporation per year = 343.689km³ water.

    * 1L / m² increasing precipitation per year = 149.43km³
    * -1.01L decreasing runoff through the rivers per year = -150.92km³
    * -0.75L decreasing groundwater level per year = -112.07km³

    Your calculator probably has a built-in joker.
    And if you are holding a PhD, you should hand it over (to me ?) as soon as possible.

  • It's albedo

    MA Rodger at 21:56 PM on 12 September, 2021

    coolmaster @92,

    Your final paragraph is packed full of unsupported assertions which you say will result from your grand scheme of annually diverting 1,335km^3/y of water that would otherwise discharge into the oceans and thus radically increase global albedo through increased cloud. The "unsupported" nature of your assertions is easily demonstrated with the two references you provide.

    ♣ The graphic you present is from Wikithing but is adapted from Abbott et al (2019) 'Human domination of the global water cycle absent from depictions and perceptions'  who provide the numbers in their Fig 3. Relevant to your grand scheme is the size of the various global water reservoirs. The giant reservoir is of course the oceans which hold 1,340M km^3. Next is ice with 25M km^3 and surface/soil water with 23M km^3 while trailing along far behind is the atmosphere holding just 0.0125M km^3 water.

    Your proposed grand scheme seems to be assuming atmospheric water can increase by 0.001335M km^3 annualy, or a 10% annual increase. Note this 10% annual increase in atmospheric water would add to the GH-effect, perhaps by some 4Wm^-2 annually, so 100x stronger than today's AGW.

    ♣ The CarbonBrief reference describes Pascolini-Campbell et al (2021) 'A 10 per cent increase in global land evapotranspiration from 2003 to 2019' which is iteslf paywalled [Abstract] but the reported 10% increase in evaporation rate 2003-19 over land equates to some 7,000km^3/y while the reported 3% increase in rainfall equates to 3,300km^3/y and the decrease in direct discharge from land to ocean a further 3,000km^3/y.

    This suggests your grand scheme wouldn't make a ha'p'orth of difference. Evaporation over land is shown to have increased five-time the amount you propose yet AGW and SLR continued apace.

  • It's albedo

    Philippe Chantreau at 03:03 AM on 12 September, 2021

    I've followed this exchange somewhat distractedly, but now I'm noticing this from coolmaster when confronted with the lack of cooling that has happened from exactly the physical process he argues would cause it:

    "NO. The water consumption of civilization and agriculture has increased steadily with the population growth.
    Agriculture in particular, as the largest consumer, has already dangerously lowered and polluted the water table in many places. Consumption continues to rise and the switch to river and rainwater is actually inevitable."

    How does that constitute any kind of response? It is completely beside the point and has nothing to do with the initial argument that the retained water would promote cloudiness, change albedo and lower temperatures. From that point of view, where the water comes from is irrelevant. The fact remains that the cooling imagined by Coolmaster from the physical process he described has not happened.

  • It's albedo

    Bob Loblaw at 11:49 AM on 11 September, 2021

    coolmaster @ 82:

    Congratulations. Another comments policy violation. You can't find anything using Google? Maybe if you look at the Skeptical Science Team page, you will find some clues about my background and why your Google search failed.

    It is amusing that you complain about a lack of links or references, when you still have yet to provide a reference for your claim that local surface evaporation will lead to a 1% increase in cloud cover. Just in case you have forgetten it, here is your original claim again:

    This volume can be retained by a wide variety of measures before it flows into the oceans and converted into evaporation. - 9L / m² corresponds to ~ 1% of the average annual rainfall over land and should therefore create ~ 1% additional clouds over the land mass.

    You repeat a diagram previously linked to. Let's us try to find the evidence we seek in that diagram.

    • Cloud cover data? Yes, for three types (high, middle, and low).

    • Clear annual cycles, especially for middle and low.

    • Global total cloud cover? We don't see sums, but it is obvious that the low and middle cloud amounts are counter-cyclical... when one goes up, the other goes down. Less variation in high cloud. Could it be possible that these cloud types are responding differently to whatever the seasonal cycles are? Maybe there are changes in geographical distribution? Maybe differences between land and sea?

    • Trends over time? Yes, And different trends for different cloud types.

    Oh, there is that pesky cloud type issue again. Maybe it's actually important?

    Now, let's look for evaporation data, so we can finally verify the elusive "1% increase in evaporation causes 1% increase in clouds" story.

    Hmmm. I'm looking hard, but I don't see it.

    • I see "atmospheric water". Is that "evaporation"? I don't think so. I seem to remember that "evaporation" is a flux from the surface to the atmosphere, not the storage in the atmophere.

    • Are we looking at a system where increased evaporation is actually causing these cloud changes? I see no evidence of that.

    • Oh, wait. Coolmaster has pointed out that this graph shows "...clouds feedback during the last decades triggered by a warming atmosphere..." My mistake - I thought you were trying to show data that supported your grand theory.

    This is typical of what coolmaster has produced here: links to papers or diagrams, with no explanation as to how they are supposed to support his argument, leaving the reader to try to examine the paper or diagram in search of something only coolmaster sees. There is no "there" there.

    You seem to like the IPCC reports. Since you appear to have a copy of AR6, I'll skip linking to it. Maybe it has something to say about your grand theory that irrigation can increase evaporation and cool the planet.


    Oh, maybe this is it!

    Section Land use.

    It mostly covers albedo changes for land, but the second last paragraph says: "The contribution of irrigation (mainly to low cloud amount) is assessed as –0.05 [–0.1 to 0.05] W m -2 for the historical period (Sherwood et al., 2018)."

    Hmmm. With those error bars, it's hard to tell if the effect is positive or negative. It's also the total effect attributable to all the increases in irrigated land over the historical period. If the -0.05 number is correct, would there be a linear response to more irrigated land, so that 100x the historical area would lead to -5W/m2 and offset the CO2 forcing? How much water is used each year for current irrigated land?

    That might give coolmaster a glimmer of hope. Why has he not presented this information before? Maybe the more detailed results in the reference the IPCC uses do not support coolmaster's grand theory? Maybe he just doesn't know what to look for?

    Maybe coolmaster will eventually provide us with the evidence we need, but I won't hold my breath.


  • It's albedo

    coolmaster at 09:19 AM on 10 September, 2021


    BL: you double-down on your claim of a strong cooling effect for clouds. Let's examine some actual science.

    I have already sent you the current science in this regard. The graphics for the global radiation balances all_sky, clear_sky, land & ocean were created and published by Prof. Dr. Martin Wild / ETH Zurich. He is a very nice person and lead author of the IPCC AR6 WGI Chapter 7: The Earth’s energy budget, climate feedbacks, and climate sensitivity. (Chapters 7.2.1 and are relevant for our topic.)
    You will not find our topic much more actual and precise anywhere, and if you continue to have doubts about the strong cooling influence of clouds - you should contact with Prof. Dr. M. Wild directly.

    BL: summary diagrams are summary diagrams - not detailed models."
    You will surely see that a slr volume of 1335km³ / year has to be distributed globally and that I therefore use global, summarizing radiation balances.

    Using the posted information in the explanatory file on land use and irrigation,

    you also have the opportunity to observe my claims about irrigation, cloud formation, precipitation, temperature, radiative forcing etc. on a more regional level.

    BL: condenses to form cloud, but this is not always the case. ...So will this "extra" moisture cause more clouds? Maybe. Maybe not.
    You have provided no scientific justification for this claim, or references to suitable scientific publications to support it. You are completely wrong here. You claim that there is some kind of rest room for water vapor in the atmosphere. Could you please prove that.
    99,999% of atmospheric water vapor will form a cloud before it return as precipitation. Dew e.g. is also considered to be a form of precipitation.

    BL: As a consequence of increasing evporation, the location where the evaporation occurs will also see less thermal energy transfer to the atmosphere, so temperatures are also affected.
    Yes Sir - that´s what I mean. More latent heat flux = less sensible(thermal as you say) heat flux. H²O in the air will form clouds - dry and hot air in the atmosphere will kill them. Soil and air temperatures will decrease - and that's exactly what I intend to do with my strategy. You should also know that the extra amount of 1% precipitation/irrigation/evaporation is planed to released predominantly in spring / summer allways into a relatively unsaturated, dry and hot clear_sky atmosphere, which most closely corresponds to a drought period or desert.

    Intensification of the global hydrological cycle is a robust feature of global warming, BUT at the same time, many land areas in the subtropics will experience drying at the surface AND in the atmosphere. This occurs due to a ! limited water availability ! in these regions, where the cloudiness is consequently expected to decrease.

    Your speculations about different clouds, with their different effects on the albedo and SW / LW radiation effects, are not conducive to the discussion and are unimportant for my assessments. In a dry, hot, sunny high pressure atmosphere, I guess at least that mostly convective fair-weather clouds or thunderclouds (cumulus or c.-nimbus) will arise.

    1% more precipitation / evaporation will not have a major impact on the general cloud pattern. The natural regional variability of the amount of precipitation is often 200mm or more between dry and humid years. Since 9mm more or less per year will regionally cause no noticeable changes in the cloud regime. Maybe there will be 3-4 rainy days/year instead of increasing hours of sunshine.
    BL: Coolmaster's diagrams are nice pictures that help illustrate a few aspects...
    Again - these diagrams are not mine. They are calculated by professionals of IPCC experts. You have no clue about the difference between water- & air cooling, heat capacity & efficiency. That's your problem - not mine.

  • It's albedo

    coolmaster at 10:43 AM on 3 September, 2021

    Also in response to blaisct's comment #66 posted over on the Urban Heat Island discussion. 

     The albedo is relative ... and depends primarily on the wavelength of the light that hits the body. We should therefore always specify a wavelength range for Albedo. Otherwise, strictly speaking, the entire spectrum of the sun is decisive. This relativity to the albedo is particularly important for an element as widespread worldwide as H²O.

    As water vapor, it absorbs (28W / m²) largely only in the long-wave range and lets most of the visible light pass through.

    As liquid water on the surface, it absorbs long-wave and short-wave light very strongly, although as a cloud in the same aggregate state, finely distributed in the atmosphere, it again reflects a high proportion (-47W / m²) of the high-energy, short-wave radiation.

    As solid ice or snow on the surface, it reflects short-wave radiation as well as clouds. On the other hand, in the long-wave range it behaves like a black body and a layer of ice over the open sea isolates the one below
    warmer water and prevents it from emitting its heat radiation to the atmosphere and space which in turn relativizes the ice albedo effect.

    So @bleisct is not that wrong if he ascribes the Earth's albedo a major influence on global temperatures. The atmosphere (and every single component - including CO² molecules) also has an albedo if the solar spectrum is viewed holistically across all wavelength ranges and light refraction and transmission are taken into account as factors. Higher levels of GHG lower earth`s albedo by absorbing ~20% of radiation energy.

    @MA Rodger is right when he remarks that the cloud albedo ingeniously has the strongest albedo and the global albedo(change) is of very minor importance over urban areas.

      With a global mean surface albedo of 13.5% and net shortwave clear-sky flux of 287 Wm−2 at the TOA this results in a global mean clear-sky surface and atmospheric shortwave absorption of 214 and 73 Wm−2, respectively. From the newly-established diagrams of the global energy balance under clear-sky and all-sky conditions, we quantify the cloud radiative effects(CRE) not only at the TOA, but also within the atmosphere and at the surface.

    The cloud-free global energy balance and inferred cloud radiative effects

     Illustration of the magnitudes of the global mean shortwave, longwave and net (shortwave + longwave) cloud radiative effects (CRE) at the Top-of-Atmosphere (TOA), within the atmosphere and at the Earth’s surface, determined as differences between the respective all-sky and clear-sky radiation budgets presented in Fig. 14. Units Wm−2 

    When assessing the earth`s albedo, it`s also helpfull to have a look to the different radiation balances from land and sea and the fact that the cloud albedo is very closely interlinked with latent heat flux of evaporation in the radiation balance. 

    Do not confuse the strongly cooling CRE (-19W / m²) with the warming cloud radiative feedback CRF of ~ + 0.42Wm-2 ° C-1, which is a missing +RF in the above graphic by @Bob Loblaw as is also the radiative forcing of the ice Albedo effect.

    .The energy balance over land and oceans

    The energy balance over land and oceans

  • The new IPCC Report includes – get this, good news

    MA Rodger at 19:26 PM on 15 August, 2021

    anticorncob6 @1,

    The CO2 budgets quickly become very complicated and comparing them takes a little spade-work. Here is my simplistic take on it.

    That 2013 Carbon Budget you link to is quite a generous one, even though it is for +2ºC AGW. Its 1,000Gt(C) emissions budget or 3,664Gt(CO2) with an Airborne Fraction of 45% would yield [1,000 x 0.45 / 2.13 + 275ppm=] 486ppm atmospheric CO2 by 2090 (followed by negative emissions). Other Carbon Budgets, for instance the IPCC SR1.5 budget from 2018 set a budget at 432ppm for a 66% chance of avoiding +1.5ºC AGW, this with large negative emissions to follow the reaching of zero. (My assessment here using the simplistic Af=45%.) The AR6 SSP1-2.6  with its 2% annual reductions for a +2ºC AGW, again followed by negative emissions post 2075, I'd assess at something like 285Gt(C) post-2020 so 474ppm, not greatly less than that 2013 Budget you linked to @1. Mind the real wake-up numbers come from AR5 which put the 66%  +1.5ºC AGW at 417ppm.

    You mention the "positive feedbacks" and perhaps nigelj @2 should have added that land ice will continue melting away unless global temperatures are reduced, the worry being that Greenland will melt down (taking millennia) with warming somewhere between +1.0ºC & +2.0ºC AGW and with nothing to stop it once its summit drops down to warmer altitudes. And the stability of the West Antarctic ice is potentially even more sensitive to warming.

    Specific to being "positive feedbacks" (which melted ice fields are not unless they entirely disappear & so reduce albedo), the melting tundra is also a process which will continue for centuries without a return to a chillier climate. The size of such the feedback from melting tundra will depend on how hot we make it.

    Keeping the ice sheets intact and the tundra frozen is one of the more obvious reasons why limiting AGW to +1.5ºC is a sensible policy.

  • It's Urban Heat Island effect

    Bob Loblaw at 02:38 AM on 15 August, 2021


    I have also replied to your post # 66 over on the Albedo Effect where Michael Sweet has responded.

  • It's albedo

    Bob Loblaw at 02:35 AM on 15 August, 2021

    Also in response to blaisct's comment #66 posted over on the Urban Heat Island discussion.


    You continue to make poor choices in the numbers and calculations that you are doing. Going over your latest effort by number:

    1. You continue to select an albedo for urban areas that is too low for anthropogenic surfaces, and you have failed to cite a reference for your value. In my comment # 64 on the Urban Heat Island discussion, I gave a reference to several artificial surface materials, all with albedo values that exceed the the value you have chosen. "Urban" areas are a mix of things like grass, roads, houses, etc. You would need to calculate how much of the surface is covered by each type, and work out an albedo for an "urban" area that way. If that is what you have done, you need to show your detailed calcuations on how you arrive at the 0.08 value.

    2. There are no assumptions in the 0.31 albedo value for the earth as a whole. That is based on satellite measurements, and includes reflection from the surface, clouds, clear atmosphere, etc. Note that the only part of the surface reflection that reaches space is the part that makes it back out through the atmosphere and cloud cover. To calculate this in a model (which is what you are trying to do), you need to account for spatial variations (and daily/seasonal cycles) of solar input, surface albedo, cloud cover, and atmospheric conditions.

    3 to 14. You continue to make unreasonable assumptions about the area that is undergoing a surface change, and how it relates to population. There is no reason to think that they are related through a simple proportion.

    15 to 20. You continue to make errors in converting solar output (1367 W/m^2 measured perpendicular to the sun's rays) to an areal average over the surface of the earth. As MIchael Sweet points out, there is a factor of 4 involved, not a factor of 2. I also mentioned this in my earlier comment. If you do not understand why this is the case, then it is difficult to see how you can expect to do any useful calculations. You also need to consider seasonal variations in solar radiation distribution and seasonal albedo.

    21. Converting radiative forcing to global temperature change involves looking at the top-of-atmosphere changes (what is seen from space), not surface changes alone. To properly incorporate surface changes into a calcuation, you need to use a much more complicated model of climate response to surface albedo changes.

    22. You still get a wildy incorrect answer, due to bad data input and bad assumptions.

    I have not bothered to follow the link to the Mark Healey document you mention. If that is the source you are getting your incorrect ideas from, then it is not worth bothering. The result you quote (that albedo changes can account for all the obsvered temperature rise) is completely inconsistent with the science.

    Over at RealClimate, they have recent posted several articles on the just-released IPCC reports. One of those summarizes 6 key results. In that post, they provide the following graph from the IPCC report, which shows the estimated temperature response due to a variety of factors over the last 100 to 150 years. "Land use reflection and irrigation" is the second-last bar on the right. Note that the calculated effect is minor cooling, not warming.

    RealClimate IPCC radiative forcings

    Michael Sweet's suggestion to read the IPCC reports is a good one. I often suggest that people start with the first 1990 report, as this covers a lot of the basic climate science principles in a manner that is easier to understand for the non-expert. In the 1990 report, they mention the Sagan et al paper I linked to in my first comment. Google Scholar can probably help you fnd a free copy.

  • It's albedo

    michael sweet at 01:05 AM on 15 August, 2021


    From here: It is generally a waste of time to do your own calculations.  The albedo of urban areas cannot have changed more that 50%.  The area of urban areas is less than 1% of the Earth's surface.  A 50% change in albedo in such a small area cannot have such a large effect.

    For starters you need to devide incoming solar radiation by 4 and not 2 to account for day/night and the curvature of the Earth. 

    Vacant land converted into farmland has significant (possibly greater) changes in abedo than urban areas and is a much greater part of the Earth's surface.  The melting of Arctic ice causes a greater change in albedo than the rural/urban change does.  We see that reflected in the Arctic increasing in temperature faster than the rest of the Earth.  If urban areas caused 30% of the warming they would all be extremely hot during the day.  This is not observed.  If your calculations were correct than albedo changes would account for all of global warming and that is not what is observed.

    If you look in the just released IPCC report you will undoubtedly find a chapter on albedo change.  See what the scientists say.  An old saying among grad students is "An hour in the library will save you a week in the lab".  See what you can find in the IPCC report and come back here to inform us.

  • It's Urban Heat Island effect

    blaisct at 01:01 AM on 14 August, 2021

    Thanks All for the input. You are increasing my understanding of the albedo effect. I appreciate the articles you mentioned and see that the subject is very complex and calculations like mine are only useful for understanding the simple significance of the many variables and not useful for reaching conclusions or predictions. One general conclusion that seem to come from all the articles and papers is that albedo is most likely significant but there is not agreement on how significant, or the range of each of the variables, or the total interaction of all the albedo variables. I sure hope that the GW experts are improving their models with new NASA satellite data. Does anyone out there know how much of the current GW data (1.1’C) in the IPCC model is accounted for by albedo change?
    For entertainment only, I redid the significance of the 0.7% urban of total earth surface what if calculation to include some of the comments.
    1. The reported albedo of urban areas is about 0.08 (double the 0.04). (Albedo on a 0.0 to 1.0 scale)
    2. The reported total albedo of the earth is about 0.31. (Assume that includes clouds and urban albedo)
    3. % of earth that is urban: =0.7%
    4. The non-urban area of the earth is: 100%-0.7%= 99.3%
    5. The contribution of urban areas to the total albedo is: 0.08 * 0.7% = 0.00056
    6. The total non-urban area albedo contribution to the total is: (0.31-0.00056)/ 0.993 = 0.31162
    7. Assume the non-urban area albedo in the 1880 era was the same as today: =0.31162
    8. Current earth population is about = 7.8 B
    9. 1880 era population is about =1.3 B (Using 1880 as the approximate start of IPCC temp data)
    10. Assume the 1880 era urban area was proportional to population: = 1.3/7.6*0.7% = 0.12%
    11. The 1880 era urban area contribution to total albedo was: 0.07*0.12% = 0.0000933
    12. The 1880 era non-urban area contribution to the total albedo was: (1- 0.12%)*0.31162 = 0.311257
    13. The 1880 era total albedo estimate is: 0.311257+ 0.0000933 = 0.311351
    14. The difference in 1880 vs 2021 albedo is : 0.311351 – 0.31 = 0.00135 (or about 0.14% albedo change)
    15. The reported output of the sun reaching the earth is about: 1367 W/m^2
    16. Assume that the urban albedo is only seeing one half (balk of urban areas are in the middle half of the earth’s surface) of the above due to the curvature of the earth: 50%
    17. Average surface of the earth cloud cover: =67%
    18. Average albedo of clouds: = 50%
    19. Total sun’s output reaching cloud covered urban areas + non cloud covered urban (corrected for curvature) is : 455 W/m^2.
    20. Therefore, this energy of the albedo difference is: 0.00135* 455= 0.61W/m^2
    21. I have seen conversion factors for converting this to ‘C in earth temperature rise of 0.5 to 0.7 ‘C/W/m^2. I’ll use the 0.5.
    22. The equivalent earth temperature rise of the above albedo change from 1880 to now is: 0.61*.5 = 0.31’C

    The IPCC reported temperature rise over the 1880 to now is about 1.1’C. This what if calculation implies that a 0.7% urban area could account about 30% of this temperature rise – not insignificant.
    One of the papers (in your previous references) on land use albedo change seems to agree that man-made albedo changes (mainly in agriculture by Mark Healey are significant and could account for all the IPCC temperature rise. Mark Healey’s paper suggest that land use changes since 1910 are stronger than the UHI albedo effect.
    I am switching over to the “It’s albedo” thread. What are all the possible albedo changes since 1880?

  • It's Urban Heat Island effect

    MA Rodger at 06:51 AM on 28 July, 2021

    blaisct @62,

    Perhaps repeating some of the criticism @64:-

    You say "The IPCC seems to give man-made albedo changes low significance because it is hard to measure and hard to detect change." But difficulty does not appear to be something to dampen your enthusiasm.

    Do note that 0.04 albedo is far too low and, while potentially applicable to a sky-pointing piece of asphalt, is not applicable to urban areas. Also note that clouds float above cities forests and oceans alike and they contribute some 75% of the planet's albedo. And also note that the sun sets every evening and never rises to be overhead except at noon in the tropics. You need to divide the tropical noon-day value by four to satisfy the very simple geometry of spheres.

    radiation budget diagram

    The solar radiation actually reflected spacewards by the Earth's surface is shown in the diagram at 23Wm^-2. If by 2100AD, the planet's urban spread were somehow to reach over 0.7% of the planet's surface area (as the most extreme projection in the graphic @60 suggests is possible) and even if that 0.7% had an albedo of zero, that 23Wm^-2 would only reduce by [23 x 0.007 =] 0.16Wm^-2 which, despite the use of the most exaggerating numbers, is significantly smaller (x10 smaller) for 2100AD than the value you arrive at for today's value. Using more realistic numbers would return an insignificant result (x100 smaller).

  • It's Urban Heat Island effect

    Bob Loblaw at 06:45 AM on 28 July, 2021

    Blaisct @ 62.

    As Rob Honeycutt says, there is something clearly amiss in your calculations. Let me point out the obvious ones.

    1. You do not cite a sources for your urban albedo of 0.04. Wikipedia lists 0.04 as a value typical for fresh asphalt. Most urban areas are not fresh asphalt. I have a well-worn copy of Tim Oke's Boundary Layer Climates, where he lists typical urban surafaces as follows (p 281):

    • Asphalt 0.04 to 0.20

    • Concrete 0.10 to 0.35

    • Brick 0.20 to 0.40

    • Roofing materials (various) 0.08 to 0.35

    Your estimate of urban albedo is way too low.

    Typical natural land surfaces (Ok.e op cit, p 12)

    • Soils (wet to dry) 0.05 to 0.40

    • Deserts 0.20 to 0.45

    • Grass 0.16 to 0.26

    • Crop land 0.18 to 0.25

    • Forests 0.05 to 0.20

    You need to consider just what urban material is replacing what natural material. Then you can estimate a change in albedo. Most urban landscapes are not that different from natural ones.

    4. Global albedo is not just a surface albedo. You need to factor in cloud cover. For a global cloud cover of 50%, only half the surface is seen from space - and surface albedo changes only have half the effect you get when you ingore cloud cover. You'd need to know the cloud cover over the urban areas you are doing calculations for.

    Your estimate of the contribution of urban surface albedo is an over-estimate. A serious over-estimate.

    7 through 13. Urban area is not proportional to population. Haven't you ever noticed how much more closely packed people are in cities, compared to rural areas? Population density is not uniform. Oke (op cit, p291) notes that the urban heat island effect tends to be proportional to the log of population, not linear. You are seriously over-estimating the amount of global albedo change in relation to urban population growth.

    14 and 15. The 1367 W/m^2 figure is for a measurement perpendicular to the sun's rays, in full sun. To compare to CO2 and other forcings, you need to divide by four, as the CO2 forcing is calculated for the entire globe, perpendicular to the earth's surface - not the sunlit side perpendicular to the sun's rays.

    You are over-estimating the effect by a factor of 4.

    16. As you have the wrong forcing in W/m^2, you are getting the wrong temperature rise.

    17. Essentially, garbage in, garbage out.

    Real scientists have been doing this the right way for decades. Try this one from way back in 1979:


  • It's Urban Heat Island effect

    blaisct at 03:59 AM on 28 July, 2021

    Thanks MA Rodger, my fault, I used the % (3%) of the earth land mass that was urban instead of the % of the total earth that was urban. The number from your graph of 0.7% urban (of the total earth area) seems to agree with other published information. I assume the heat from the “heat island” effect would be well mixed around the earth and become part of the total measurement of climate change. I present the following to check out the significance of the 0.7%.
    1. The reported albedo of urban areas is about 0.04. (Albedo on a 0.0 to 1.0 scale)
    2. The reported total albedo of the earth is about 0.31. (Assume that includes clouds and urban albedo)
    3. The non-urban area of the earth is: 100%-0.7%= 99.3%
    4. The contribution of urban areas to the total albedo is: 0.04 * 0.7% = 0.00028
    5. The total non-urban area albedo contribution to the total is: (0.31-0.00028)/ 0.993 = 0.31190
    6. Assume the non-urban area albedo in the 1880 era was the same as today: =0.31190
    7. Current earth population is about = 7.8 B
    8. 1880 era population is about =1.3 B (Using 1880 as the approximate start of IPCC temp data)
    9. Assume the 1880 era urban area was proportional to population: = 1.3/7.6*0.7% = 0.12%
    10. The 1880 era urban area contribution to total albedo was: 0.04*0.12% = 0.000047
    11. The 1880 era non-urban area contribution to the total albedo was: (1- 0.12%)*0.3119 = 0.31154
    12. The 1880 era total albedo estimate is: 0.311538+ 0.000047 = 0.311585
    13. The difference in 1880 vs 2021 albedo is : 0.311585 – 0.31 = 0.001585 (or about 0.16% albedo change)
    14. The reported out put of the sun reaching the earth is about: 1367 W/m^2
    15. Therefore, this albedo difference is: 0.001585* 1367 = 2.1680W/m^2
    16. I have seen conversion factors for converting this to ‘C in earth temperature rise of 0.5 to 0.7 ‘C/W/m^2. I’ll use the 0.5.
    17. The equivalent earth temperature rise of the above albedo change from 1880 to now is: 2.168*.5 = 1.08’C

    The IPCC reported temperature rise over the 1880 to now is about 1.0’C. This calculation implies that a 0.7% urban area could account for all of that temperature rise. I know this is over simplified, and was only done to find out the significance of small changes in a higher heat source ( over 4X lower albedo in urban areas vs the earth as a whole) on the earth surface. Other factors in albedo change should also be included: roads, forest fires land area, sea ice melting, land ice melting, rain forest destruction, and farming practices. I can only guess that including these albedo changes in the above would increase the man-made albedo global warming calculation.
    The IPCC seems to give man-made albedo changes low significance because it is hard to measure and hard to detect change. Population change and even atmospheric CO2 change should also be an indicator of historical man-made albedo change, just need a reference point.

  • It's Urban Heat Island effect

    blaisct at 02:23 AM on 22 July, 2021

    Should we be looking at the surface area of the earth these differences in trends represents? These graphs would better be related to climate change if they included some correction for urban area change. Over time this urban area may be increasing (and suburban area decreasing) thus the total heat into the atmosphere is also increasing proportional to that area change. I expect that including urban area increase due to population would show a significant increase in total heat going into the atmosphere over time vs the suburban areas. When urban areas of the earth were small (less than 1%) the “heat island” effect was probably insignificant. Now that the urban area is over 3% of the earth’s surface an area correction is needed. There may also be some differences in the albedo of cities due to construction practices and population density.

  • The Albedo Effect and Global Warming

    blaisct at 06:35 AM on 20 July, 2021

    Reading about resent NASA satellite data on finding increase heat loss to space makes me wonder how this increase in heat loss is consistent with the Radiative Forcing theory of the IPCC. My understanding of that theory is that as atmospheric CO2 increase it hold in more heat and makes the surface temperature hotter like a blanket effect while the heat loss to space remains the same. The NASA data does not seem to support the Radiative Forcing theory or I must not understand the Radiative Forcing theory. Where is the extra heat coming from?

    Also reading about the “heat island” effect from big cities (up to 15’F difference between urban and suburban) makes me wonder could this be related to the NASA data on heat loss? Has population gotten big enough to have an impact on global warming? The “heat island” effect is caused by the much lower albedo (reported as 0.04, cloud free) of urban areas vs the earth as a whole (reported at 0.31). Using IPCC data one can calculate that an albedo change of only 0.15% (+1’C) is needed to account for all of the temperature change from 1880 until now. (that is a hard to detect 0.001%/year). While we are waiting on that detection level we can use related data to estimate man-made albedo change like population or atmospheric CO2.
    The earth’s urban area is reported at 3.1% of the total area of the earth. The urban area back in 1880 (start of IPCC global warming data) is estimated at 0.7% (proportional to population) over 4X change. In 1880’s the “heat island” albedo effect was probably insignificant plus there was not many black parking lots or paved roads. The IPCC reports a 1’C rise in temperature since 1880. Using published information one can calculate the heat rise of the current 3.1% urban area at 4’C rise (since 1880) in earth temperate just from the urban area albedo change. (Using IPCC data of sun’s radiation to the earth at 1367w/m^2 and surface temperature rise correlation of 0.5 ‘C/w/m^2). The calculated 4’C rise is more heat than necessary to account for the 1’C observed this is probably due the reflective increase in clouds (water evaporation that eventually become clouds and reflects sun light) that would come with more heat from urban area. This overly simplified estimate of the man-made albedo effect suggests a more scientific version of albedo change should be included in any global warming model or theory. As the population of the earth gets bigger and urban areas grow this effect will get bigger. There are also other man-made albedo effects (destruction of rain forest, forest fires, melting of sea ice, and agricultural practices) which would be proportional to their % of the earth’s surface and their individual albedos.

    The earth’s population should be a good indicator of urban area increase and thus man-made albedo change. Atmospheric CO2 is also corelated to population should also be a good indicator of urban area increase (albedo decrease). Are CO2 and albedo confounded in their correlation to global warming? Which force is bigger? The above calculation suggest albedo. NASA's ongoing map of the earth's cloud free albedo should be a big help in including albedo in global warming models, initial results seem to support the above.


  • Models are unreliable

    Bob Loblaw at 00:54 AM on 7 July, 2021


    This all hinges on what is meant by "calibration", and whether or not the parameters in a model are arbitrary.

    Wiktionary defines "calibrate" as "To check or adjust by comparison with a standard." When discussing climate models, this implies that there is some adjustable parameter (or seven) or input that can be varied at will to create a desired output.

    There are many problems with this argument [that climate models are "calibrated" to create a result]:

    • What are we calibrating for? A global 3-d climate model has thousands (if not millions) of outputs. Global mean surface temperature is one simple statistical summary of model output, but the model has temperatures that vary spatially (in 3-d) and temporally. It also has precipitation, humidity, wind speed, pressure, cloud cover, surface evaporation rates, etc. There are seasonal patterns, and patterns over longer periods of time such as El Nino. All of these are inter-related, and they cannot be "calibrated" independently. Analyzing the output of a GCM is as complex as analyzing weather observations to determine climate.

    • How many input parameters are devoid of physical meaning and can be changed arbitrariiy? The more physcially-based the model is, the fewer arbitrary parameters there are. You can't simply decide that fresh snow will have an albedo of 0.4, or open water will evaporate at 30% of the potential evapotranspiration rate, just because it makes one output look better. So much of the input information is highly constrained by the need to use realistic values. All these have uncertainties, and part of the modelling process is to look at the effect of those uncertainties, but the value to use can be determined independently through measurement. It is not a case of choosing whatever you want.

    So, robnyc987's claim that you can achieve 100% accuracy by "calibrating" a small set of parameters is bunkum. If climate models are so easy to "calibrate", then why do they show variations depending on who's model it is? Or depending on what the initial conditions are? That variability amongst models and model runs indicates uncertainty in the parameters, physics, and independent measurements of input variables - not "calibration".

    Perhaps robnyc987 will return to provide more explanation of his claim, but I somehow doubt it.

  • 2021 SkS Weekly Climate Change & Global Warming News Roundup #17

    MA Rodger at 17:49 PM on 26 April, 2021

    Dale H @3,

    Further to #3, the declining CO2 levels over the last few ten-of-million years are usually put down to errision following the Himilayan mountain-building. The Antarctic ice appeared about 35Mya on the cooling planet. On a shorter time-scale, the shutting-off of the oceans between N & S America 3 Mya ago resulted in the appearance of the Arctic ice which has been fuelling ice ages ever since.

    The frequency of these ice ages swapped from 40,000yr to 100,000yr roughly 1 Mybp (so your 1.2Mya @1). A mechanism for this transition is not entirely nailed down quite yet (eg see Chalk et al 2017 or Willeit et al 2019). However the usual suspect is the level of dust from exposed land during glacial cycles and its reduction of the ice albedo. So when the lands of northern lattitudes have been scoured clean back to the bedrock, the dust is greatly reduced and thus the albedo of the less-dusty ice caps does not decline so much during high glaciation, allowing ice a longer period before destablising into an interglacial.

  • CO2 lags temperature

    MA Rodger at 08:39 AM on 13 February, 2021

    brneilsen @629,
    I'm curious as to the origin of your 'greenhouse gas response' equation T=3.2563ln(C)-3.0323. And if there were any merit in such an equation, I'd be interested to learn how it 'yields' a "0.95 degC" boost to global ice age temperatures resulting from a 190ppm to 280ppm rise in CO2. My abacus (which I would be the first to admit is not always reliable) 'yields' +1.26ºC using this bizarre equation.

    The usual calculation of CO2 forcing is ΔF = 5.35 x ln(CO2[1]/CO2[0]) which gives a forcing of +2.07Wm^-2 and a thus 'direct' impact on global temperature of+0.56ºC which would cause climate feedbacks that would perhaps triple this value to +1.7ºC.
    The global average temperature rise out of an ice age is usually reckoned at +5ºC to +6ºC so this calculated CO2 forcing would perhaps be responsible for a third of this temperature rise. And this result fits with assessments which find the contributions to deglaciation warming to be roughly 50% surface albedo, 37% GHGs (of which CO2 is the major player) and 13% atmospheric albedo.

  • Increasing CO2 has little to no effect

    MA Rodger at 21:27 PM on 12 February, 2021

    devcarr @427,
    I assume your surprise at the graphic @425Response showing the AGW temperature rise halting as soon as emissions stop because your questioning didn't expect the residual warming-yet-to-come to be pretty-much balanced by the reduction in climate forcing. Following the end of emissions, the GHGs are no longer being boosted by those emissions but instead falls as GHGs are naturally drawn out of the atmosphere.

    Perhaps your expected a response to your question @425 to be for the time for warming to end and equilibrium to be reached for a constant level of GHGs. This is of course a different question.

    The radiative imbalance is running at something like 1 Wm^-2 and if that were allowed to play out by keeping GHG levels constant, it would take a century or more before equilibrium is effectively achieved, with ECS=+3.0ºC suggesting an additional +0.8ºC. The time for this is uncertain as it is the longer-term processes that are poorly quantified when the ECS is assessed, and the value of ECS is famously poorly bounded.

    Hansen et al 2011 fig4

    The left-hand graphic here is Fig 4a from Hansen et al (2011) 'Earth’s energy imbalance and implications'. It shows a large part of the warming-to-come appearing in the first decade and that followed by a further large part in the following century. The big uncertainty is in the longer-term warming and this is the major cause of ECS being so poorly defined. And that long-term warming is not entirely a thermodynamic thing. Major longer term warming due in albedo can be caused by a minor and quite insignificant temperature imbalance acting over a long period. So any such long-term warming will result from the warming-already-achieved (+1.0ºC) as well as warming-to-come (+0.8ºC). And so if climate forcing were maintained, this longer term could then become quite significant.

  • There's no empirical evidence

    Philippe Chantreau at 07:12 AM on 25 January, 2021


    The fact that you feel you can be sentencious and pontificate on such obvious elements as the atmosphere being transparent to solar light reveals that you have not done anywhere near enough reading to form an informed opinion that will hold any value. Everyone who contributes here is well aware of everything you just said. I could be pedant and add that temperature decreases with altitude up until you hit the tropopause, then things get a little more complicated.

    And incidentally, both albedo (which you hint at without naming it) and aerosols have been studied extensively. They are the subject of an entire body of scientific litterature, and are an examined item of denial at SkS: It's aerosols

  • It's waste heat

    MA Rodger at 22:27 PM on 17 January, 2021

    Climate Detective  from elsewhere, [link URL not being uploaded ]

    Forgive me for demonstrating the major fallacies within your grand work but as you say "The calculations are not difficult to do."

    The assertion you make that "All energy generation by humans results in an output of heat or thermal energy" is fundamentally wrong. It is "power" that is generated and when this is through the application of kinetic energy from passing fluids, through the burning of recently grown plant matter or from intercepting solar energy that would otherwise be absorbed by the ground, there is not net increase of the planet's surface energy. It is only the absorbing of albedo-decreasing solar energy, the splitting of heavy atoms or the burning of fossil fuels to release chemical energy that does result increased the planet's surface energy.
    Further your attempts to suggest a significant level of climatic warming in an area such as the UK is due to these increases in surface energy ignores what would be the absence of such warming in adjacent areas where there is effectively no such surface warming, like the North Sea, the North Atlantic or for that matter, the whole of Africa. Taken over the whole globe, the UK is exceptional as it uses ~1% of global primary power but within ~0.05% of the global surface area. Because, as with all small areas of the globe, UK temperatures are very much dictated by the adjacent climate, the global average is the relevant value and that is trivially small. (Generally the energy released by FF use is exceeded by the GHG effect of the CO2 thus released in 9 to 18 months, depending on the type of FF employed.)

  • 2021 SkS Weekly Climate Change & Global Warming Digest #1

    MA Rodger at 01:37 AM on 13 January, 2021

    Dr. S. Jeevananda Reddy @16,

    ♥ Indeed, your book Reddy, S.J., (2008) 'Climate Change: Myths & Realities' is mostly available to read on a Google Books preview up to page 87 but pages 88-193 "are not shown in this preview".

    ♥ And nobody would mistake the critique within the 'blog' by William Connolley as your work.

    ♥ As for your assertion that my use of the adjective "erroneous" is not backed up by science, that is yet more "erroneous" input from you.
    I haven't read past your comment @6 but that yields conclusive findings for me.
    Your suggestions that solar or wind power are contributing to global warming is plain silly. A wind farm mixes air, and actually extracts energy locally to be transported for use elewhere. Temperature increases are simply the result of mixing of air, not the generating of warming.
    A solar farm will decrease albedo but the additional solar energy absorbed is comparable to the waste heat from a fossil-fuelled or nuclear powerplant. And this is without the CO2 from a fossil-fuelled powerpalnt which will add to AGW.

    Any positive climate forcing raises global temperature and this in turn will be amplified by feedbacks, particularly through the resulting higher specific humidity.
    Thus you write condescendingly @6: "increased CO2 raises temperature slightly and that produces an increase in water vapour, which does have the capability of raising atmospheric temperature" but with the added comment "However, it is not the case." So how is it that a climate forcing from increased CO2 (at 3.7wm^-2 per doubling) does not increase global temperature and thus initiate further warming from feedbacks? What scientific principle could you invoke to argue such a thing?

  • 2021 SkS Weekly Climate Change & Global Warming Digest #1

    Dr. S. Jeevananda Reddy at 17:47 PM on 11 January, 2021


    Global Warming: It is an estimate of the annual average part of temperature trend. The trend of 1880 to 2010 is 0.6oC per century in which global warming component is 0.3oC – 1951 to 2100 is 0.45oC – according to linear trend. But in reality it is not so as the energy component is constant over which superposed sunspot cycle. However, the reliability depends up on the data used. For example number of stations in around 1850 were < 100 and by around 1980 [started satellite data collection started around this time] they were more than 6000 and with the availability of satellite data the number of stations drastically come down to around 2500. The satellite data covered both urban-heat-island effect and rural-cold-island effect and showed practically no trend – US raw data series also showed this. However, this data was removed from internet [Reddy, 2008 – Climate Change: Myths & Realities, available on line] and replaced with new adjusted data series that matches with ground data series. Here cold-island effect is not covered. With all this, what I want say is warmings associated with solar power plants is added to global warming. How much?? This needs collection of data for all the solar power stations. Met station covers a small area only but acts like UHI effect – I saw a report “surface temperatures in downtown Sacramento at 11 a.m. June 30, 1998 – this presents high variation from area to area based on land use [met station refers to that point only]. So, solar wind power plants effect covers similar to heatwaves and coldwaves. Here general Circulation Pattern plays main role.

    Nuclear Power: Nuclear power production processes contribute to “global warming process” while hydropower production processes contribute to “global cooling process”; the nuclear power production processes don’t fit into “security, safety & economy” on the one hand and on the other “environment & social” concepts; unlike other power production processes, in nuclear power production process different stages of nuclear fuel cycles are counted as separate entities while assessing the cost of power per unit and only the power production component is accounted in the estimation of cost of power per unit; carbon dioxide is released in every component of nuclear fuel cycle except the actual fusion in the reactor. Fossil fuels are involved in the mining-transport-milling conversion-processing of ore-enrichment of the fuel, in the handling of the mill tailings-in the fuel can preparation-in the construction of plant and it decommissioning-demolition, in the handling of the spent waste-in its processing and vitrification and in digging the hole in rock for its deposition, etc. and in the manufacturing of necessary required equipment in all these stages and thus their transportation. In all these stages radiological and non-radiological pollution occurs – in the case of tail pond it runs in to hundreds of years. Around 60% of the power plant cost goes towards the equipment, most of which is to be imported. The spent fuel storage is a critical issue, yet no solution was found. Also the life of reactors is very short and the dismantling of such reactors is costly & risky, etc., etc.

    Michael Sweet/ Negelj

    In 70&80s I worked and published several articles relating to radiation [global solar and net and evaporation/evapotranspiration] – referred in my book of 1993 [based on articles published in international and national journals]. Coal fired power plants reduces ground level temperature by reducing incoming solar radiation. In the case of Solar Panels create urban heat island condition and thus increases the surrounding temperature. In both the cases these changes depends upon several local conditions including general circulation patterns. Ground condition plays major role on radiation at the surface that define the surface temperature [hill stations, inland stations & coastal stations] – albedo factor varies. Also varies with soil conditions – black soil, red soil. Sea Breeze/land breeze – relates to temperature gradient [soil quickly warm up and quickly release the heat and water slowly warm up and slowly release heat] and general circulation pattern existing in that area plays the major role in advection.

    Response to Moderator

    See some of my publications for information only:

    Reddy, S.J., (1993): Agroclimatic/Agrometeorological Techniques: As applicable to Dry-land Agriculture in Developing Countries, Books, 205p; Book Review appeared in Agricultural and Forest Meteorology, 67 (1994):325-327.
    Reddy, S.J., (2002): Dry-land Agriculture in India: An Agroclimatological and Agrometeorological Perspective, BS Publications, Hyderabad, 429.
    Reddy, S.J., (2008): Climate Change: Myths & Realities, Books, 176.
    Reddy, S.J., (2016): Climate Change and its Impacts: Ground Realities. BS Publications, Hyderabad, 276.
    Reddy, S.J., (2019a): Agroclimatic/Agrometeorological Techniques: As applicable to Dry-land Agriculture in Developing Countries [2nd Edition]. Brillion Publishing, New Delhi, 372p.

    2.1.2 Water vapour

    Earth’s temperature is primarily driven by energy cycle; and then by the hydrological cycle. Global solar radiation reaching the Earth’s surface and net radiation/radiation balance at the Earth’s surface is generally estimated as a function of hours of bright Sunshine. Total cloud cover [average of low, medium & high clouds] has a direct relation to hours of bright Sunshine (Reddy, 1974). Cube root of precipitation showed a direct relation to total solar radiation and net radiation (Reddy, 1987). In all these latitude plays major role (Reddy & Rao, 1973; Reddy, 1987). Evaporation presents a relation with net and global solar radiation (Reddy & Rao, 1973) wherein relative humidity plays an important role that reduces with increasing relative humidity. If ‘X’ is global solar radiation received under100% relative humidity then with the dryness [with relative humidity coming down] it may reach a maximum of 2X; and under net radiation also with increasing relative humidity net radiation is reduced. That means water vapour in the atmosphere is the principal component that controls the incoming and outgoing radiation and thus temperature at the Earth’s surface. Thar Desert presents high temperature with negligible water vapour in the atmosphere as maximum energy reaches the earth’s surface. However, these impacts differ under inland (dryness), hill (declining temperature with height – lapse rate) & coastal (wetness) locations and sun’s movement (latitude and declination of the Sun — seasons) (Reddy & Rao, 1973). IPCC integrated these under “climate system” and the advective condition by general circulation pattern [GCP].
    Cold-island effect [I coined this, see Reddy (2008)] is part of human induced climate change associated with changes in land use and land cover. Since 1960’s to meet the food needs of ever increasing population, started intensive agriculture – conversion of dryland to wetland; & creation of water resources; etc. In this process increased levels of evaporation and evapotranspiration contributed to raise in water vapour up to around 850 mb levels in the lower atmosphere. Unusual changes in water vapour beyond 850 mb level [for example at 700 mb level] become a cause for thunderstorm activity (Reddy & Rao, 1978). Wet bulb temperature (oC) at the surface of the Earth provides the square root of total water vapour (g/cm2) in the vertical column of the atmosphere; and also wet bulb temperature (oC) is a function of dry bulb temperature (oC), relative humidity (%) and square root of station level pressure (height) relative to standard value in mb [p/1060] (Reddy, 1976). Thus, unlike CO2, water vapour presents a short life with steadily increasing with land use and land cover changes. However, met network in this zones have been sparse and thus the cold island effect is not properly accounted under global average temperature computations. Though satellite data takes this in to account, this data series were withdrawn from the internet and introduced new adjusted data series that matches with adjusted ground data series. Annual state-wise temperature data series in India wherein intensive agriculture practices are existing, namely Punjab, Haryana & UP belt, showed decreasing trend in annual average temperature – cooling. Some of these are explained below:

    Reddy (1983) presented a daily soil water balance model that computes daily evapotranspiration, known as ICSWAB Model. The daily soil water balance equation is generally written as:

    ▲Mn = Rn – AEn – ROn - Dn

    In the above equation left to right represent the soil moisture change, rainfall or irrigation, actual evapotranspiration, surface runoff and deep drainage on a given day (n). The term Actual Evapotranspiration [AEn] is to be estimated as a function of f(E), f(S) & f(C), wherein they represent functions of evaporative demand on day n, soil & crop factors, respectively. As these three factors are mutually interactive, the multiplicative type of function is used.

    AEn = f(En) x f(S) x f(C)

    However, the crop factor does not act independently of the soil factor. Thus it is given as:

    AEn = f(En) x f(S,C) and f(S,C) = K x bn

    Where f(S,C) is the effective soil factor, K = soil water holding capacity [that varies with soil type] in mm and bn is the crop growth stage [that vary with crop & cropping pattern] factor that varies between 0.02 to 0.24 — fallow to full crop cover conditions (with leaf area index crossing 2.75). Evaporative demand is expressed by the terms evaporation and/or evapotranspiration. Evaporation (E) and evapotranspiration (PE) are related as:

    PE = 0.85 x E [with mesh cover] or = 0.75 x E [without mesh cover].

    However, the relationship holds good only under non-advective conditions [i.e., under wind speeds less than 2.5 m/sec]. Under advective conditions E is influenced more by advection compared to PE. In the case of PE, by definition, no soil evaporation takes place and thus PE relates to transpiration only – where the crop grows on conserved soil moisture with negligible soil evaporation. With the presence of soil evaporation, the potential evapotranspiration reaches as high as 1.2 x PE or E with mesh cover. McKenney & Rosenberg (1993) studied sensitivity of some potential evapotranspiration estimation methods to climate change. The widely used methods are Thornthwaite and Penman presented 750 mm and 1500 mm wherein Thornthwaite method is basically uses temperature and Penman uses several meteorological parameters (Reddy, 1995).
    In this process the temperature is controlled by solar energy but moisture under different soil types [water holding capacity] it is modified. This modified temperature cause actual evapotranspiration and thus water vapour. This is a vicious circle. For example average annual temperature in red soils Anantapur it is 27.6oC; in deep black soils Kadapa it is 29.25oC & in medium soils Kurnool it is 28.05oC. That means, local temperature is controlled by soils.
    Reddy (1976a&b) presented a method of estimating precipitable water in the entire column of the atmosphere at a given location using Wet Bulb Temperature. The equations are given as follows:

    Tw = T x [0.45 + 0.006 x h x (p/1060)1/2]

    W = c’ x Tw2

    Where T & Tw are dry and wet bulb temperatures in oC; h is the relative humidity in %; p is the annual normal station level pressure in mb [1060 normal pressure in mb, a constant] ; W is the precipitable water vapour in gm/cm2 and c’ is the regression coefficient.
    WMO (1966) presented methods to separate trend from natural rhythmic variations in rainfall and assessing the cycles if any. (Late) Dr. B. Parthasarathy from IITM/Pune used these techniques in Indian rainfall analysis. Reddy (2008) presented such analysis with global average annual temperature anomaly data series of 1880 to 2010 and found the natural cycle of 60-years varying between -0.3 to +0.3oC & trend of 0.6oC per century [Reddy, 2008]. This is based on adjusted data series but in USA raw data [Reddy, 2016] there is no trend. The hottest daily temperature data series of Sydney in Australia shows no trend [Reddy, 2019a]. Thus, the trend needs correction if the starting and ending point parts are in the same phase of the cycle – below and below or above and above the average parts. During 1880 to 2010 period two full 60-year cycles are covered and thus, no need to correct the trend as the trend passes through the mean points of the two cycles.

    3.2.4 What is global warming part of the trend?

    According to IPCC AR5, this trend of 0.6oC per century is not global warming but it consists of several factors:
    a. More than half is [human induced] greenhouse effect part:
    i. It consists of global warming component & aerosols component, etc. If we assume global warming component alone is 50% of the total trend, then it will be 0.3oC per Century under linear trend;
    ii. Global warming starting year is 1951 & thus the global warming from 1951 to 2100 [150 years] is 0.45oC under linear trend;
    iii. But in nature this can’t be linear as the energy is constant and thus CSF can’t be a constant but it should be decreasing non-linearly;
    iv. Under non-linear condition by 2100 the global warming will be far less than 0.45oC and thus the trend will be far less than half;
    b. Less than half the trend is ecological changes [land use and land cover change] part – mostly local & regional factors:
    i. This consists of urban-heat-island effect and rural-cold-island effect;
    1. Urban-heat-island effect – with the concentrated met network overestimates warming;
    2. Rural-cold-island effect – with the sparse met network underestimates cooling;

    2.2.1 Uncertainty on “Climate Sensitivity Factor”

    The word “climate Crisis” is primarily linked to global warming. To know whether there is really global warming, if so how much, climate sensitivity factor plays the main role. Climate sensitivity is a measure [oC/(W/m2)] – how much warming we expect (both near-term and long-term) for a given increase in CO2? According to Mark, D. Zilinka (2020), “Equilibrium climate sensitivity, the global surface temperature response to the CO2 doubling, has been persistently uncertain”.
    Recent modelling data suggests the climate is considerably more sensitive to carbon emissions than previously believed, and experts said the projections had the potential to be “incredibly alarming”, though they stressed further research would be needed to validate the new numbers. Johan Rockström, the director of the Potsdam Institute for Climate Impact Research, said. “Climate sensitivity is the holy grail of climate science. It is the prime indicator of climate risk.
    The role of clouds is one of the most uncertain areas in climate science because they are hard to measure and, depending on altitude, droplet temperature and other factors can play either a warming or a cooling role. For decades, this has been the focus of fierce academic disputes. Catherine Senior, head of understanding climate change at the Met Office Hadley Centre, said more studies and more data are needed to fully understand the role of clouds and aerosols. With this vital disputes how anyone can say there is global warming without solving this issue; so I said “global warming hysteria factor is climate crisis”.


  • Milankovitch Cycles

    scaddenp at 13:28 PM on 5 August, 2020

    Hmm I think Hansen & Sato calculated this and reported in AR4. More like 4% for global solar change, 21% for albedo change and remainder from GHG (CO2 + CH4). However, locally (65N) the milankovich forcing is very high, enough to determine whether snow melts out in summer or not and so trigger the large scale albedo changes.

  • Climate sensitivity is low

    Cedders at 01:29 AM on 24 July, 2020

    The big news announced yesterday is the narrowing of equilibrium climate sensitivity (ECS) from a combination of paleoclimate and historical measurements and feedback modelling, a study which will feed into IPCC AR6. As I understand it, ECS is now very likely (90% likely) to be within 2.0‐5.7 °C, and likely (66% probability) to be 2.6‐3.9 °C, with a longer tail above 4.5 °C than below 2 °C. Anyone 'gambling' on low sensitivity would lose. Sherwood et al, "An assessment of Earth's climate sensitivity using multiple lines of evidence", Reviews of Geophysics, 2020.

    The following long review tells me more than I need to know about feedbacks of all kinds: Heinze et al, "Climate feedbacks in the Earth system and prospects for their evaluation", Earth System Dynamics, 2019.
    Although there may be 'black swan' events and earth-system feedbacks, the idea that climate scientists aren't including albedo or cloud changes in models is incorrect.

    More recent info on feedbacks in the latest CMIP6 models is in Meehl et al, "Context for interpreting equilibrium climate sensitivity and transient climate response from the CMIP6 Earth system models", Science Advances, 2020. and Zelinka et al, "Causes of Higher Climate Sensitivity in CMIP6 Models", Geophysical Research Letters, 2020., the latter including a nice figure S7 showing the contribution of different feedbacks in different models.

  • Models are unreliable

    Tom Dayton at 08:36 AM on 5 July, 2020

    Deplore_This: Also, you seem to be overweighting the practical importance of the exact value of sensitivity. If you're in a car 200 feet from a rock wall, heading directly toward that wall, it doesn't really matter much if your speed is 50 or 60 miles per hour; the consequences are bad enough in either case that you should be applying the brakes right now. For climate change there is the additional urgency that the problem gets worse as time goes on, so even if sensitivity is on the low end, that merely delays the same bad consequences by an inconsequentially few years. Yet another time urgency comes from the fact that the primary causes (in particular greenhouse gas emissions) and feedbacks (e.g., lower albedo from loss of ice) are impossible to reverse on time scales that will be useful. Ice loss, for example, effectively is permanent on human timescales. Another problem with delaying action is that warming accelerates due to feedbacks, sort of like interest accruing on a loan. The longer you wait to pay, the more money you need to pay.

  • 2020 SkS Weekly Climate Change & Global Warming News Roundup #25

    Eclectic at 20:06 PM on 22 June, 2020

    Lawrie @9 , Slarty Bartfast maintains that there is no global warming of any significance at a statistical level or at a physical planetary level.   So to him, albedo is irrelevant.

    Being more than 24 hours since his last posting, it seems unlikely that Slarty will return to attempt rebuttal of criticisms of against his many positions.  But we can hope he will return, to give a grand explication of his apparent errors and inconsistencies.

    In order to save the valuable time of SkS readers, I have looked further into Slarty's blog of May / June 2020 , and I have pulled out some points of interest.   Slarty's statistical/mathematical skills are (IMO) far exceeding his climate science knowledge  . . .  and somehow I am reminded of the very emeritus & climatically-challenged Ivar Giaever !

    I have taken some care not to misrepresent or quote-mine Slarty.   And please note that Slarty, in his blog, describes himself as: physicist / socialist / evironmentalist.

    1.   Sea level rise cannot be more than slight , because there is no CO2-AGW or CO2-led Greenhouse effect.  And so our coastal cities have zero danger of submersion.

    2.   What little CO2-greenhouse effect is present now, is produced by CO2 reflecting IR back to the planetary surface.

    3.   Weather stations fail to give valid planetary data because they are far too few, and (just as importantly) they are not evenly spaced.

    4.   "temperature records just aren't long enough ... to discern a definite trend ... you need at least 50 years."

    5.   "[land ice] In Antarctica (and Greenland) this is virtually all at altitude (above 1000 m) where the mean temperature is below -20 C, and the mean monthly temperature NEVER gets above zero, even in summer.  Consequently, the likelihood of any of this ice melting is negligible."

    6.   AGW forcing does not supply enough heat to melt ice at the poles [he seems to include the Arctic, too].

    7.   The Arctic is not warming.  [Presumably news to those alarmist Inuit who live there.]

    8.   Berkeley Earth Study repeats the sins of Hadley/ NOAA / etc but in a more transparent way ~ and BEST generates a falsely-positive warming trend through its misuse of Breakpoint Adjustments (rather than using raw data).

    9.   Slarty's oceanic thermal expansion calculations are wrong [as pointed out by MA Rodger].

    And there's more !

  • 2020 SkS Weekly Climate Change & Global Warming News Roundup #25

    Lawrie at 11:34 AM on 22 June, 2020

    Any process that absorbs visible light decreases albedo. Photosysnthesis, the process that produced fossil fuels, would seem to be way ahead of solar power. Following on from Slarty's logic then the quickest way to reduce global warming would be to clear fell all the earth's forests and replace them with reflective concrete

  • 2020 SkS Weekly Climate Change & Global Warming News Roundup #25

    Climate Detective at 08:42 AM on 21 June, 2020

    I noticed that one of the proposals of this article is more solar power. Yet solar power decreases the Earth's albedo and thereby increases local surface warming. This warming (even without CO2 greenhouse emisions) can be as high as 1 degC as I note here -

    In thermodynamics there is no such thing as a free lunch. All human activity warms the planet. So what is the plan? Go back to prehistoric living and get everyone to live in a cave?

  • How much would planting 1 trillion trees slow global warming?

    baeb at 03:16 AM on 9 June, 2020

    There are several characteristics of forests that aren't mentioned as far as I can see in the article or the posts.  (1) Mature forests sequester a large amount of carbon in soil micro-biology mainly through large amounts of mycorrhizal fungi and their creation of humates.  This will build over time and remain there.  (2) Tree leaves represent laminate surfaces containing water so their temperatures change slower than air around them, so they condense water as dew and in many places condense large amounts of water. (3) Roots and dead tree matter particularly on slopes reduces runoff and rapid evaporation so water helps cool forests (4) Forests change the amount of water in an area in many other ways.  Rainfall and snow doesn't evaporate as easily in shade as in fields or parking lots so it is released slower and tends to contibute to more vegetation growth. The difference is large in hot areas. (5) As I understand it, forests don't emit mid and far-range infrared as much as an adjacent area of earth, rock, pavement, etc. because they don't get hot and cool themselves through transpiration.  This increases water vapor in the air along with nucleating pollen, that contributes to rain down wind which encourages more biomass.  Water vapor becomes clouds which can create albedo themselves, rain for more plants, lower temperatures blocking sun, but of course they also operate as greenhouse gases so there are some questions there. But water that goes up also comes down.

    The work of Prof. Walter Jahne (online) is interesting on this and there were at least two Science magazine articles on the modeling 20 years ago of rain, vegetation, and climate alteration.  Which is to say that the effect of forests on global temperatures is, just like climate, a very complicated issue.  But I would like to know what anyone with expertise in both forest ecology and climate thinks about these issues (if there is such a person) and its relation to the important topic of the crisis we face and what to do about it.

  • We're heading into an ice age

    Lawrence Tenkman at 05:16 AM on 27 April, 2020

    MA Rodger,

    Thank you so much for your kind resopnse. I much appreciate you. Very interesting. So complex.

    It seems that the article by Willeit & Ganopolski (2018) suggest that much dust comes from the equatorial advancing edge of the glacier (erosion from the advancing ice edge as I understand?)… not necessarily plant death as Ellis & Palmer suggest. Also, albedo blunting for glaciation escape is not accomplished by dust alone… albedo is increasingly blunted by the increase of both snow age & of dust accumulation, combined together. Perhaps this explains the lack of a critical level for the dust as a single factor blunting albedo… as multiple factors that combine to do it.

    Those equations made my head hurt. I feel like a patient sitting in a doctor’s office asking questions and expecting them to make me understand concepts it took years of medical school to understand. For sure, that’s not possible, as I’d have to go through all the training you did… year by year ... more answers leading to more questions.

    But I do appreciate you very much. Thank you for taking the time.  Thank you for doing what you do.


  • We're heading into an ice age

    MA Rodger at 23:47 PM on 26 April, 2020

    Lawrence Tenkman @407,

    To clear up the "parting comment", it appears in a 2015 blog-post linked at the last paragraph of #405 above. The denialist flavour of this "parting comment" does explain some of the very odd comment in Ellis & Palmer (2016).


    The 'CO2 mechanism' I say is not explained is specific to the glacial maxima. Ellis & Palmer (2016) demonstrate temperature, dust and CO2 are correlated (in their figs 1, 4, 8 & 9). We could also include sea level/ice volume and methane into such correlations. So the question arises - What is driving what?
    During the drop into an ice age we can be reasonably confident that reduced northern insolation allows a build-up of northern ice sheets reducing regional albedo which has a global impact on temperature and kicks-off positive feedbacks in albedo, CO2 & methane.

    But the glacial maxima appear to have a particular pattern to them, perhaps clearest when sea level is considered. The Ice Ages step up a gear as they dive into the maxima.Ice Age Sea Level

    Ellis & Palmer point the finger at the CO2 feedbacks. They would have difficulty using albedo as the dust-levels are building at these points in the Ice Age cycle and Ellis & Palmer dismiss the idea of atmospheric dust-levels being a significant cooling factor.

    Given the constraints placed on the workings of Ice Age maxima by Ellis & Palmer, their hypothesis seems to rely on some strong CO2 feedback that comes into play at this point in the Ice Age cycle. So my question - Are the measurements of CO2 showing a big enough reduction?  What is causing these large reductions in CO2? And what causes these reductions to quickly reverse when the maxima is over?


    And not greatly removed from any discussion of 'CO2 mechanism'....

    Regarding the lack of 'threshold' for dust levels to bring Ice Ages out of their maxima, Ellis & Palmer Fig 4 (below) shows great variation in the peak level of dust as well as variation in the duration of high-dust prior to the glacial maxima. This I term a lack of 'threshold'. The general impression is that a generally high level of dust reducing albedo of global ice sheets awaits the increase in nothern insolation caused by the Milankovitch cycle.

    But surely this variability means the power of the dust-reduced albedo forcing is not strong enough of itself to be the trigger. It is possible that analysis would show the Milankovitch cycle and the dust-albedo in combination provides a consistent threshold level, or perhaps CO2 levels are also a factor in the mix. But such necessary analysis would require an approach somewhat less simplistic than Ellis & Palmer. (For instance, compare the Ellis & Palmer approach with that of, say, Willeit & Ganopolski (2018).)

    Ellis & Palmer fig 4

    I think that covers the issues from #407, hopefully in an understandable form.

  • We're heading into an ice age

    Lawrence Tenkman at 05:40 AM on 26 April, 2020

    Scaddenp & MA Rodger,

    Thank you so much for your responses.

    MA Rodger, thank you for reading that article an phelping me with it. Please clarify a few things for me if you don’t mind. You mentioned that "Ellis & Palmer fail to explain the mechanism driving the CO2 reduction and why this cooling doesn't keep on going… and that the peak-dust levels do not appear to have a threshold level." My impression from reading was they propose Earth gets cold enough at the nadir of orbital Milankovitch cycle to start forming ice, and if enough ice forms, albedo is sufficient resist subsqeuent Milakovitch warming cycles, and Earth plunges into into a glacial period via increasing of both ice formation & ice albedo feedback. Ellis & Palmer suggest CO2 falls because the cold makes the ocean draw CO2 in (increased solubility of the cold water) and this CO2 drop is what stops further cooling, b/c plant death from low CO2 & low temp causes the dust.

    It all sounded interesting to me… but even if their theory about dust were true about glaciation exit mechanisms, I don’t think it would be right to conclude that infinitely high man made CO2 & greenhouse doesn’t matter in today's world. This website has so much data suggesting we need to care.

    I’m not sure what you mean by: "the peak-dust levels do not appear to have a threshold level." What does that mean? Threshhold referring to a temp or CO2 level at which dust forms? Threshhold referring to a level of dust at which it is can melt ice? I thought the dust elevations seemed to occur during temperature & CO2 nadirsand seemed to precede warming consistently.

    Ellis & Palmer’s parting comment wasn’t in the website link I had ( (“So the only evil in this world is not in the atmosphere, it lies in the hearts of those who wish to starve plants and animals of their most essential food supply — CO2.”). But on YouTube, I did hear Ellis suggest we may be put here by “intelligent design” to burn fossil fuels to save us from an ice age. Sounded a bit off to me…. and made them seem quite biased. Hence, I wanted to hear from someone more educated that me on these concepts. Thank you so much for discussing this with me.

  • We're heading into an ice age

    Eclectic at 05:13 AM on 26 April, 2020

    MA Rodger , geoengineering climate by distributing iron (as fertilizer) to pelagic ocean, has been discussed in previous years.

    Tim Conway & Seth John (2014, Nature ) indicated that a large proportion of North Atlantic ocean-water iron was deriving from Saharan dust.

    There has been some more casual  discussion of the idea of dust from dry land similarly producing algal bloom and thus a reduction of atmospheric CO2.   This climate-cooling mechanism (which I have not seen quantified) would act in opposition to the dust-albedo mechanism suggested by Ellis & Palmer (2016) .

  • We're heading into an ice age

    MA Rodger at 23:24 PM on 25 April, 2020

    Lawrence Tenkman @402,

    I did manage a read-through of Ellis & Palmer (2016). I note it isn't published properly which is likely why it fails to get mentioned within the literature. (It is published here but only as an “unedited manuscript” which was to “undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form.” I see no “final form.”)

    There is within Ellis & Palmer mention of “another story for another day” with the suggestion that this would add to the grand theorising with explanations of Dansgaard-Oeschger events and the mid-Pleistocene transition. A paper co-authored by Ellis has appeared on the web explaining the pre-MPT 41ky Ice Age cycle as resulting from there being an extra southern-driven version of the Ice Age cycle which post-MPT ran out of land in the post-MPT permanently-iced-over Antarctica and leaving only the northern-driven post-MPT 100ky Ice Age cycle.

    I'm not sure how the pre-MPT cycles would fit in with the Ellis & Palmer theory of dusty interglacial-triggering. (The appearance of interglacials in beat with the orbital eccentricity wobble is described in this follow-on thesis as purely coincidental. The frequency is defined by the 70ky it takes to prime the system with ice.)

    The absence of proper follow-on work, of publication or of citations is a kiss of death to theories such as set out by Ellis & Palmer. But that does not explain what it says or why it is wrong to say it.

    Ellis & Palmer (2016) is a poor piece of work. It occasionally says some very silly things but I shall ignore those. It also gallops past the science rather than addressing it, indeed describing it as “scientific lacuna.” But I shall here ignore such hubris.

    The grand theory presented explains that the precession/obliquity within the Milankivitch cycles does not always lead to an interglacial and that this is not immediately explained by CO2/albedo alone. To cause an interglacial Ellis & Palmer invoke a dusty atmosphere which reduced ice albedo and, as warming takes hold, adds to this albedo reduction when warming brings greater levels of dust to the melting ice surface.

    They say the dust results from reduced CO2 which causes lower tree-lines globally and this increasing dust as plant-less dusty mountain tops grow into dusty mountains and then dusty hills with the lowered tree-line. A correlation of dust and CO2 is presented. This dust-correlation could be made with many other different factors so is effectively an exercise in curve fitting with the low-CO2>>high-dust relationship remaining speculative.

    What is also not explained in all this is the mechanism driving the CO2 reduction and why this cooling doesn't keep on going. The peak-dust levels do not appear to have a threshold level and if there is a CO2/ice-volume/Milancovitch/dust mechanism at work it has yet to be convincingly demonstrated.

    So without further work beyond those referenced here, work to fill in the gaps and thus enable this allegedly important theory to be properly published, it is fair to say that not a great deal has been done since the initial appearance of this work in 2015 which was then, with its parting comment “So the only evil in this world is not in the atmosphere, it lies in the hearts of those who wish to starve plants and animals of their most essential food supply — CO2. “, certainly more work concrened with denialsim than with scientific analysis.

  • We're heading into an ice age

    Lawrence Tenkman at 00:44 AM on 23 April, 2020

    MA Rodger & Scaddenp,
    Thank you so much for your quick responses.

    MA Rodger, very interesting. So dust-albedo blunting has always been a proposed mechanism for glaciation escape, but perhaps at MPT, the source for the dust “dried up” so it stayed cold longer? Ellis says MPT is beyond this paper’s scope, but he has a line suggesting that elevation of the Himalayas may have influenced MPT. Ellis suggests the earth beneath dying forests as a source for dust. His theory is: forests die from combination of low temp and low CO2 (both of which lower at higher elevations). I was just curious of what you thought of the correlation he found with dust in his graphs at the end. The paper’s first page or so lays out his premise. The charts and graphs are interesting, especially the one at the end where it shows temperature & CO2 drop, followed dust formation, followed by temperature rise. I thought it looked convincing. But I lacking the knowledge most of you have, am not qualified to critique it. If you have a moment, would you mind?

    Scaddenp, your response draws on knowledge that I don’t have (synchronous southern glaciation showing CO2 being driver), and thus I cannot follow. Forgive me. I'm not sure what you mean about the denial of phyiscs.  I know CO2 air concentration can affect temp (greenhouse) and temp can affect CO2 air concentration (water solubility). (Is that what you were referring to?). Ellis says that going into glaciation, temp drop caused CO2 drop. He says CO2 was 190 ppm, but it got low enough to affect trees at certain elevations (where partial pressure is low enough to reach a critical level of 150-160). He has a chart showing temp and CO2 concentration at various elevations in tropical and alpine regions. So far, I’m impressed with his data, but hesitant with his conclusions (in light of other overwhelming data)… but my level of knowledge makes my critique of limited value.

    My goal is to read this entire website… this happens to be just one nugget I’m trying to digest at the moment.

  • We're heading into an ice age

    MA Rodger at 05:03 AM on 22 April, 2020

    Lawrence Tenkman @399,

    While I'm not familiar with the paper you enquire about, Ellis & Palmer (2016), I note it not referenced by the likes of Willeit et al (2019) (which may be why I've not encountered it before).

    On the subject of dust-driven albedo forcing, the Ice Age cycle does present one puzzle addressed by Wileit et al and that is the mid-Pleistocene transition - when Ice Ages changed from a 41ky cycle to a 100ky cycle a million years ago. My (evident) weak understanding of the literature is that a potential candidate mechanism for the MPT rests with the repeated Ice Ages scouring the high-latitude landscape back to bare rock that then reduced the source of dust during the depths of an Ice Age and thus reduced the power of the negative dust-albedo feedback, this reduced power allowing Ige Ages to last 100ky rather than 41ky.

  • We're heading into an ice age

    Lawrence Tenkman at 03:11 AM on 22 April, 2020

    Ralph Ellis suggests that the warming that ends glaciation is not from CO2 greenhouse effect, but instead dust storms cancelling albedo on northern ice sheets. He proposes that the inertia of natural cycles is towards glaciation: cold orbit forcings eventually start ice sheet formation, which adds albedo, which adds cold & more ice sheets, etc. When it gets cold enough, oceans draw in CO2, and at a critical point (low enough temp & low enough CO2) rapid plant death ensures at certain elevations. This allows for erosion / dust storms, which land on ice sheets to cancel their albedo. Although the dust effect he speaks of would not have as widespread effect throughout the world, it would have a local strong effect on the ice to break the feedback process. Because the critical cold temperature may take several Milankovitch cycles to reach, his theory may explain why not all Milankovitch spike result in glaciation escape. I’m curious what experts think about his theory. (I am not an expert.) To me it seems to make sense and seems like a very disciplined paper. Maybe he uncovered the a key strong variable for escape of glaciation.

    In light of his dust-albedo cancellation being a strong effect, Ellis then concludes that CO2 is too weak to threaten overheating us or runaway greenhouse effect, and we shouldn’t worry about it… afterall CO2 of 280 ppm had too weak an effect (about 3.7 W/m2?) to prevent entry into glaciation. Ellis suggested that its almost like we were put here to burn fossil fuels to prevent an ice age.

    I hesitate to follow him to all of his conclusions though. For one, why the two must be mutually exclusive? If his strong local “trigger” indeed matters more for glaciation exit, why must CO2, which is cumulative, lasting, global, & rapidly rising not matter at a high enough level in our situation? I’m most concerned that temp is quickly rising despite cooling forces from solar & orbital cycles… and we’ve only begun to make CO2 at a very rapid rate.

    In terms of “preventing an ice age”. Many above suggest we’ve already prevented or much delayed it. Also, many above suggest, CO2 is like a gas pedal that recoils slowly once pressed. Future generations could always press the pedal further if determined necessary for ice age avoidance thousands of years in the future. But if we determine that we’ve pressed it too far, and are now in danger… too late. Can’t draw CO2 down rapidly.

    I’m no expert though… so I’d much appreciate an expert’s reflection on the significance of Ellis’s paper.

  • Milankovitch Cycles

    MA Rodger at 03:33 AM on 31 March, 2020

    mkrichew @32elsewhere,

    The inclination of our slightly-less-than-round Earth doesn't appear to impact the area subject to insolation by very much. The Earth's dimensions are given as a polar minimum radius of about 6,357 km and an equatorial maximum radius of about 6,378 km. If we were to consider the Earth as an elipsoid with these dimensions, its area facing-the-sun with a pole pointing at the sun would be just 0.3% greater than with the tropics-facing-the-sun but that would be assuming the axis is tilting through 90º relative to the sun and staying there throughout the year. Yet the actual change in tilt is nothing like 90º and is only fully acting at the solstices.

    The tilt varies between 22º & 24½º through its 40,000 year cycle, so just a 2½º variation, and that inclination is achieved relative to the sun only at the solstices, twice a year. So the increase in Earthly area facing the sun would vary by perhaps (0.3% x 3% x 70% =) 0.006% or a forcing of  very roughly  0.015Wm^-2. That's only about 4-months-worth of AGW so not exactly significant. And bear in mind the bigger winter/summer temperature range at the two poles resulting from any increase in tilt. That would firstly see more energy leaking away into space (as the energy loss to space is T^4 so a constant temperature is more energy-efficient than hot-summer:cold-winter) and secondly the albedo change from the greater area of winter snow will reduce solar warming. These two cooling effects should well-exceed the warming from the greater earthly area catching the sun from there being a greater axial tilt.

    (Note also the calculated effect of orbital eccentricity in the link @54 is 0.167%, some 30x greater. Even with this larger increase in insolation leads John Baez to the conclusion "if changes in eccentricity are important in glacial cycles, we have some explaining to do.")

  • The pros and cons of planting trees to address global warming

    John Wise at 00:31 AM on 25 March, 2020

    JoeZ: I didn't find it negative, but it is cautionary, and aimed at those who might think that all we need to do is plant trees, or who think that trees can be planted anywhere and thrive. The diminishing of the albedo of the far north by planting there was news to me(mind you, it is still so cold and dry there that few trees would grow).

  • The pros and cons of planting trees to address global warming

    RedBaron at 00:26 AM on 25 March, 2020

    As I have stated many times here at Skeptical Science, this is the wrong biome.

    Trees do have their ecosystem functions and obviously protecting and restoring forests is a good thing, but it is not the biome responcible for cooling the planet. Thus this is more like using AGW as an excuse to plant trees rather than an actual solution designed to reverse AGW.

    I am glad Dana Nuccitelli wrote about the flaws in using the wrong biome to reverse AGW, but I am surprised how resistant people are, even here.

    Allan Savory has come on this very site and tried to explain it. Probably by far the best expert scientist on the planet regarding grasslands restoration and how this in fact is the correct biome to accomplish the task.

    I myself have posted significant numbers of published science when and where I can find it. And I have been doing this for years here.

    We can even trace the original tree planting idea back to a "merchant of doubt" denial and obfuscation proposed by Freeman Dyson. He did have some minimal expertise, but not really in the climate science field long enough to be considered a reliable source.

    Yet this "tree planting" myth still persists over actual working scientists that have dedicated their entire lives to this one specialty? I am always confounded by this. Is it really so hard to understand that carbon on the surface is more likely to decay back into the atmosphere than stay sequestered long term as the carbon deep below the surface? Is it so hard to understand that C4 grasslands have much higher albedo, lower humidity from transpiration, and much higher efficiency of photosynthesis, while putting all these "ecosystem services" under the surface where they are protected?

    I have no problems with planting trees when and where we can, but really this is not helping much. 

    And please. Lets be honest here. The real reason the grasslands solution is being ignored or discounted is due to all the prime bits of land being already in intensive agricultural production. Oh and by the way the very reason they are "prime bits of land" is generally because of the very fact they were at one time either grassland or savanna and have already sequestered vast amounts of carbon before we plowed them up. In fact they already did what the pseudoscience claims is imposible. 

    I really seriously can't understand why of all places on the web, at least you guys can't get this very important part of climate science right. And please don't just delete of mod clip this post. Because if you'll just answer at least I can go try and find you some good citations to address them.

  • Increasing CO2 has little to no effect

    Eclectic at 21:24 PM on 9 March, 2020

    (Checking to see if my post uploads successfully to SkS)

    Thank you, MA Rodger.   Mr Dakota was quite off-target in trying to picture things in relative CO2 concentrations such as 0.041% or 410 parts per million.

    As you say, the presence of water vapor adds a large complication ~ except for Mars.   Adjustments also for albedo or reflectiveness at non-visual wavelengths . . . plus or minus reflectiveness of sulfate aerosols from industrial and/or volcanic origin.   Other adjustments for Earth's tilt or seasons, and for clouds at different heights & latitudes.

    The climate scientists certainly have their work cut out for them, to get a handle on it all.   Mr Dakota is probably tempted to think it's much easier just to be a science-denier, and firmly close one's eyes to reality !

  • It's CFCs

    EGS at 23:59 PM on 6 March, 2020


    Are you claiming that the degree of northern hemisphere ice albedo is a trivial amplification feedback in anthropogenic radiative forcing? 

  • Skeptical Science New Research for Week #9, 2020

    MA Rodger at 20:31 PM on 6 March, 2020

    swampfoxh @1,

    Your question doesn't 'ring any bells' with me and the authors you mention don't seem to lead anywhere that I can see.

    The 1,500 year timescale is occasionally mentioned as the time it takes the ocean waters to re-appear at the surface and so reach CO2-quilibrium with the atmosphere. That is part of what Goreau (1990) 'Balancing Atmospheric Carbon Dioxide' addresses but it is not the same as timescales for temperature equilibrium under otherwise-fixed CO2 levels.

    Rohling is the lead author of Rohling et al (2009) 'Antarctic temperature and global sea level closelycoupled over the past five glacial cycles' and this does consider multi-millennial equilibrium timescales but this concerns sea level. There is a connection in that the melt-out of, say, Greenland would both impact sea level and temperature as the albedo change constitutes a slow climate feedback (see this SkS post). But over such multi-millennial timescales with Milankovitch cycles in operation, it would require more than "modest" climate forcings to be significant.

    More directly addressing your question, the ice cores do show a small increase in CO2 levels over the last 8,000 years. This would provide roughly a 0.3Wm^-2 climate forcing which (slow and fast feedbacks so perhaps a sensitivity of 6ºC) could have given a total temperature rise of +0.5ºC. Yet spread over eight milennia, any residual effect today would be now miniscule.

    CO2 graph 10000 years

  • How much would planting 1 trillion trees slow global warming?

    RedBaron at 14:36 PM on 26 February, 2020


    US started planting trees in the 1920's and there are at least as many now as the pilgrim days or more.

    What is different is the prairies. Most of them have been plowed under, especially the tallgrass prairie.

    You can look on Google Maps all you want, but just because you see an area without trees doesn't mean there was a forest there before. In most cases it was prairie.

    Unplowed Tallgrass Prairie: Rarer Than Old-Growth Forest

    This is important because grasslands are the planets cooling system, not forests. 

    Cenozoic Expansion of Grasslands and Climatic Cooling

    You are seeing the reason why right now in Australia. Above ground biomass always returns to the atmosphere eventually either by decay or my fire.

    Whereas a large % of the carbon (~40%) fixed by grasslands is stored deep in the soil profile. And a high % of that carbon (~70%) enters the geological long cycle and does NOT enter back into the atmosphere for thousands or even millions of years.

    Then there is also the albedo effects, where trees absorb much more radiation and grasses reflect more due to averaging a much paler green coloration. 

    The US easily plants as many or more trees than they log and have been doing this for about 100 years. So already many trees planted have already grown up and been logged again, and replanted again.

    However, as I said before, this does not mean the US isn't contributing to AGW. They certainly are. But the primary ways are because of fossil fuel emissions and plowing up and destroying the biome responcible for cooling the planet...grasslands.

  • Climate's changed before

    scaddenp at 10:26 AM on 26 February, 2020

    Bruce. Hard to know where to begin.

    CO2 does not reflect sunlight - the gas is transparent to the frequencies of radiation coming from sun. However, the gas absorbs infrared radiation leaving the surface. So GHG lets energy in but slows energy going out.

    A warming ocean will emit CO2 (melting permafrost and temperate wetlands are other sources of GHG as temperature rise), but the oceans will not become net emitters of CO2 for hundreds of years. Currently they are absorbing CO2 (and becoming less alkaline).

    The situation at the end of an ice age is different - the changing distribution of sun energy (milankovitch cycles) result in summer melt in high northern latitudes reducing the albedo (and thus the amount of sunlight reflected directly back to space from ice). The warming releases GHG by the various mechamisms and as a result whole planet warms.

  • Climate's changed before

    KR at 02:50 AM on 25 February, 2020

    theSkeptik - " I would assume that both greenhous gases and temperature are correlated to other parameters"

    Well, yes, because physics. Long lived non-precipitating greenhouse gases in the atmosphere (CO2, CFCs, Methane) reduce IR emissions to space from the top of the atmosphere, which causes an imbalance of energy in the climate against incoming sunlight, and the climate therefore warms until radiated energy once again equals incoming.

    Along the way there are feedbacks both (mostly) positive and (some) negative which on the whole amplify the temperature response, such as changing CO2 solubility in the oceans, changing Earth albedo by melting snow over darker landscapes, methane releases from warming permafrost, and as a fast response changes in absolute humidity due to warm air holding more water vapor (itself a greenhouse gas, although as a feedback, not a driver).

    Physics comes first - correlation analysis to determine the exact amplitude of the response between drivers and the climate comes later.

  • Australia's wildfires: Is this the 'new normal'?

    Bob Loblaw at 11:50 AM on 20 February, 2020

    Mark: you say "...the more I see it needs to be a bigger part..."

    Note that the paper you found has a list of references. Note that the earliest of those references is from 1987.

    I can also point you to a paper from 1979:

    Anthropogenic Albedo Changes and the Earth's Climate

    Carl Sagan, Owen B. Toon, James B. Pollack

    Science 21 Dec 1979:
    Vol. 206, Issue 4425, pp. 1363-1368
    DOI: 10.1126/science.206.4425.1363

    Studying changing surface effects on climate is not new. This is not something the climate science community is unaware of.

  • Australia's wildfires: Is this the 'new normal'?

    Eclectic at 11:32 AM on 19 February, 2020

    Mark Thomas , in my own simple understanding of things ~ deforestation has a global warming effect because woody carbon is released to raise the atmospheric CO2 level (and the replacement grasslands or cultivated fields are much lower in carbon mass . . . also, cultivated soil tends to lose some of its stored carbon, too).

    OTOH, grasslands & farmland have a higher albedo, and thus some cooling effect ~ but not enough to counterbalance the CO2 effect.  Then there are other complexities, such as the methane produced in rice-fields.

    It would be difficult to determine whether small-region climate changes (e.g. in the Australian continent) could be brought about by deforestation.  "Micro-climate" might well be cooled by evaporation from tall forests ~ but I am a touch sceptical about the evaporative difference between grassland/agri-fields and virgin land of the scrubby or semi-arid type (of which Australia has always possessed a vast amount).

    Soil moisture may not be very important ~ since on dry lands the greater temperature during the day is counterbalanced by the lower temperature at night.

  • Earth is heating at a rate equivalent to five atomic bombs per second

    MA Rodger at 21:44 PM on 16 February, 2020

    Regarding the energy from burning fossil fuels, there is an SkS graphic illustrating the relative size of the various global energy inputs.

    I feel that 3.7Wm^-2 figure requires some further explaining. It is the value of Climate Forcing, the global energy imbalance, that would result from a doubling of CO2 which, without feedbacks, would result in a global temperature increase of +1ºC. These values are explained by the solar warming (less albedo) being globally 240Wm^-2 which thus gives an effective planetary temperature of (240/5.67e-8)^0.25 = 255K. Add 3.7Wm^-2 and it becomes 256K. These values, of course, apply high up in the atmosphere but the temperature increase from any forcing also applies to the surface temperatures as the lapse rate acts in a linear fashion down through the atmosphere.

    Additional to the initial forcing, there are feedbacks which increase the warming. They act as the global temperature rises, this temperature rise meaning the initial climate forcing is being equalised. Thus the feedbacks do not appear as an increased energy imbalance but instead extend the temperature effect of the climate forcing as it equalises with rising temperature.

    Now, at any particular time during AGW (where the Climate Forcing is applied slowly over a period and not all at once) the energy imbalance which is warming the globe (and so theoretically available to melt Greenland ice) will be far smaller than the accumulative Climate Forcing since pre-industrial times. Much of this Climate Forcing (and as negative forcings are poorly defined, the value of net Forcing since pre-industrial is imprecisely known but it is usually quoted as very roughly 2Wm^-2) will have been balanced by the global temperature increase since pre-industrial. It is solely the remaining energy imbalance that is available for melting ice caps, this running presently at something like 1Wm^-2.
    From the imbalance, there is then perhaps something like 16ZJ/year entering the climate which, if it could be brought to bear on Greenland's ice, would melt Greenland in something like 50 years. Of course, getting all that energy imbalance to Greenland would be impossible but if the ice were to set off across the oceans, it does become possible. Indeed, having melting icebergs bobbing about at lower latitudes would lower the global temperature and this will increase the global energy imbalance. (This is the mechanism behind the hypothesis set out in Hansen et al 2016.)

    Hope all that makes sense.

  • Milankovitch Cycles

    Map at 07:04 AM on 3 February, 2020

    Scaddenp thank you, that graph show exactly what I was looking for.  Interesting that it shows the opposite of what I was comprehending before with the albedo on land mass.

  • Milankovitch Cycles

    scaddenp at 06:25 AM on 3 February, 2020

    The change in albedo from human constructions etc. is is under "Land use" in the breakdown forcings.


    This is discussed (with references to the source data) in Chapter 8, section 8.3.5.  If you havent already read the the IPCC report, then you should so before leaping in here.

  • Milankovitch Cycles

    Map at 03:52 AM on 3 February, 2020

    Ok a quick question.  I am seeing throughout the comments that people are correlating milankovitch's theory with albedo and ocean current to "explain" how solar insolation and ocean co2 can add to the temperature effects of the milankovitch theory.  The question that I have is;   Is there a way that the extra structures that man have put on the land mass in the northern hemisphere and the factor that we move so much snow to expose the ground to make travel easier possibly changing the albedo effect on solar insolation and combining with our increased co2 output to amplify our current global warming?

  • CO2 lags temperature

    Eclectic at 22:50 PM on 2 February, 2020

    In reply to commenter "Map" , from the other thread :-

    Map, we must be careful to avoid semantic problems/confusions, so it is best if we all communicate in the standard scientific language (i.e. meaning of terms).  You will mislead yourself if you use terms such as "minor ice ages"  every 21000 years and "major ice ages"  every 43000 years.  For that is not what the well-established Milankovitch theory indicates.  (See ice-albedo , CO2 feedback, etcetera.)

    You haven't said exactly, but you seemed to be referring to Greenland ice cores (such as GISP2 from central Greenland).  Their data comes from local conditions ~ not from global temperature changes.

    There have been interestingly large/rapid swings in temperature shown in GISP2 data, but these are are mostly around the unusual event of the Younger Dryas . . . and do not reflect a basic global climate change (nor the inflow/outflow of heat energy which is the underlying cause of climate change).

    For the sudden rise you mentioned, please permit me to quote climate expert Richard Alley :-  "[temperature increase was] for Greenland, and applies moderately well around the North Atlantic, primarily as a wintertime change because there was a rapid shift from wintertime sea ice to wintertime open water in important regions.    ... I can provide lots of chapters and verses on all of this, but the skinny version is that when the abrupt shifts happened, they primarily involved circulation rather than greenhouse gases, they didn't do a lot to global mean temperature, but they did do a lot to regional climates in many places, with large, rapid changes in North Atlantic temperatures, rapid shifts in monsoonal rains and in the edges of the tropical rain belts, smaller shifts in northern temperatures away from the North Atlantic, and lagged and opposite shifts in southern temperatures (so northern warming was followed by southern cooling)".

    Map, I hope that provides you somewhat of a help.  Please note that the big swings in the GISP2 proxy temperature data . . . are often displayed in the Deniosphere (of science-denying websites) ~ where it is implied that it's a world temperature chart.   Worse, the GISP2 graph ends at 1855 (yes, eighteen fifty five ~ quite before the modern AGW temperature rise began) . . . and the chart scale is so compressed, that the casual reader is misled into believing past temperatures were much higher than modern times.

    Denialist websites, such as WattsUpWithThat [WUWT] are well-known for these types of deceptions & falsehoods.   Map, if that's where you've been getting some of your information/misinformation . . . then you have been handicapping yourself.   WUWT contains all sorts of propaganda ~ and a lot of mutually contradictory crackpottery . . . and the comments sections there are half-filled with people who are still in complete denial of the basic physics of CO2 radiational properties.   Really a snake-pit of intellectual insanity !

  • It's magma

    Eclectic at 17:41 PM on 23 January, 2020

    Cpske ~ check out the Myth #196 of the Most Used Climate Myths (top left corner of page).

    The short story : climate is changed by alterations in the 240 watts/squ.meter absorbed by the planetary surface.  The 240 figure changes somewhat with solar changes ~ alterations in solar output, over the longer term or over the 11-year solar cycle) . . . or is changed by ice-albedo alterations . . .  or is changed by major volcanic eruptions throwing aerosols into the stratosphere . . . or is changed by man-made industrial pollution aerosols . . . or is changed by alteration in the levels of Greenhouse gasses (of course).

    OTOH, the flow of heat from the depths of the Earth is at an average rate of 0.09 watts/squ.meter ~ so very tiny that it is rightly  ignored in climate measurements & calculations.  This geothermal heat flow data is determined from temperature measurements take at a range of depths in deep boreholes.   There's no evidence of significant variation in this geothermal flow, nor any reason to believe it could alter the climate ~ even over thousands of years.   Yes, there are magma plume hotspots (such as formed the Hawaii islands) but they are fairly steady . . . and any new hotspots are too small in area to change the planetary average (the Earth's surface area being 510 million square kilometers).

    Cpske, if it's not too much trouble for you, I would be interested in having a look at the "static" you mentioned.   I regularly have a look at some of the Deniosphere blogs ~ such as WattsUpWithThat [WUWT], which does occasionally (well, rarely!) have articles of minor scientific interest.  But mostly the WUWT articles are rather childish propaganda . . . and the comments columns are 95% full of crackpot ideas & political ultra-extremism & more general intellectual insanity & recycled long-debunked climate "theories".  WUWT can be amusing, if you find amusement in Schadenfreude.   But I haven't noticed any "geothermal nonsense" there recently.   

  • Water vapor is the most powerful greenhouse gas

    SkepticalBrian at 04:51 AM on 16 January, 2020

    there are a too many comments on here to review, maybe I misse it, but can anyone explain how irrigation is NOT a significant contributor to greenhouse effect? The evaporative cooling is often cited as a climate cooling effect which is incorrect, as the energy used in evaporation is merely transported elsewhere and released during condensation. The albedo of the otherwise arid lands is changed and the re-radiation to space is diminished As heat sinks into the ground more. So the constant irrigation of millions of ha of land worldwide does not constitute a "short lived" WV effect, it is a constant significant factor. Any land that need to be irrigated at all is contributing. Plus, all the hydrocarbons burned created a continuous stream of WV. 

  • I had an intense conversation at work today.

    barryn56 at 15:05 PM on 15 January, 2020

    Eclectic @ 10. No, not toying. As I mentioned, I'm not going to tell you what to think, nor claim that the earth's temperature or climate is not changing. If you are really concerned about these factors, then the effort should be in understanding the problem before trying "solutions", less you make matters worse, not better.

    You can first of all consider that scientists are human; they have the same failings as all of us, myself included. Take, for example, the assertion by scientists that aircraft con trails were a source of atmospheric warming - for the very same reasons the claims for greenhouse" effect. During the moratorium on flights over the US for 3 days, the opposite was found, so why were they wrong?

    If you research the physics, the Earth is modelled as a Black Body, so all the energy from the Sun is received and re-emitted (otherwise temperature would continue to rise). The temperature expected is calculated based on the source strength, the reflection (albedo) of the body and the orbital radius. A common theme in researchers is that the difference between the exected temperature (251K) and the "average" temperature (288K) is the warming effect of the "greenhouse" effect of the atmosphere (about 30 degrees C). Well, you can check that theory yourself by checking the BB radiation and surface temperature of a celestial body that is essentially the same distance from the Sun as the Earth, but has no greenhouse gases. You will find its daytime temperature is 400K - about 130degC, while the BB temperature is calculated at 272K - about 0 degC. So does the moon have a 130 degC greenhouse effect? So direct measurement - no theory here - shows a body at our distance from the Sun is much hotter than the estimated BB radiation calculation. Anyone who owns a dog probably has a good idea what controls the temperature on Earth... Next, we can delve into the spectrum and absorption, the basis for the "greenhouse" effect.

  • SkS Analogy 21 - Snow on a Hot Tin Roof

    Evan at 01:44 AM on 25 December, 2019

    Fred@5 Good points. A quick Google search turns up the following papers on this subject that might be of interest (here and here). So yes, it appears that trees have an initial warming effect until they soak up enough carbon to offset the warming they cause by reducing albedo with respect to an open field. I think it safe to say that burning down rainforests has a warming effect, because the release of carbon has a much higher warming effect that the increased albedo caused by replacing mature trees with open fields.

  • SkS Analogy 21 - Snow on a Hot Tin Roof

    Fred Kaluza at 19:32 PM on 24 December, 2019

    speaking of the albedo effect then, all other things being equal, would a tan and dust-covered planet be warmer or cooler than a dark blue and green colored planet of the same size at the same distance from the sun?  My point is that I think a planet covered with trees will actually get warmer than a bare planet, at least until those trees can soak up a lot of the CO2 and change the atmosphere's ability to trap heat.  My point is that planting trees will actually make it least in the short run.

  • SkS Analogy 21 - Snow on a Hot Tin Roof

    Evan at 01:34 AM on 21 December, 2019

    Darinscoop@2 The ice-Albedo feedback describes a spontaneous change in Albedo with time, whereas the heat-island effect describes a contrast of Albedo (i.e. cities have lower Albedo than surroundings areas), which does not spontaneously change with time, unless we deliberately cause a change through development or other urban planning.

  • Search For 'Missing Heat' Confirms More Global Warming 'In The Pipeline'

    michael sweet at 22:15 PM on 29 November, 2019


    Good luck pinning down warming in the pipeline.  This is a much discussed topic.  

    One problem is different scientists use different definitions of the term. Make sure you are comparing apples and apples.

     Hansen has estimated a long term Whole Earth Equilibrium.  That used to be double other estimates but it may have been changed.  As the ice sheets melt (over hundreds of years) albedo goes down, causing more warming. Sea ice melt has started this change already.  Do you care about the pipeline for the next 50 years or the final temperature in 1000 years? 

    Sea level rise is the same.  Recent estimates of 600 million refugees by 2100 (for a moderate rise estimate) do not discuss equilibrium sea level rise (the last time CO2 was over 400 ppm sea level was 23 meters higher!!!).  

    You did not mention the delay caused by deep ocean warming.  The ocean is a gigantic heat sink that will take hundreds of years to come to equilibrium.  Sometimes 40 years is used for just the upper layers to warm.

  • It's the sun

    scaddenp at 12:55 PM on 7 November, 2019

    socialfox - estimates of climate sensitivity seek to answer what would the change of temperature for a given effective increase in radiation at TOA. Changes in GHG concentration, albedo are back-calculated to an effective change in TOA radiation. ie. As if the incoming solar radiation was changing. The direct contribution to radiative flux from a change in GHG is a known quantity (~4W/m2 for a doubling, which falls out the Radiative Transfer Equations and has been empirically verified in various ways). It is not something deduced from the temperature response, but resultant feedbacks (water vapour, albedo, cloud cover) that contribute to actual change in temperature are not well known and hence the wide range of estimates for climate sensitivity. Climate sensitivity is estimated from a variety of methods including paleoclimate and models.

    Note that models do not assume a climate sensitivity - it is an emergent property from the model so I dont see the circularity.

  • CO2 was higher in the past

    nyood at 07:02 AM on 7 November, 2019

    I want to subsequently deliver a source that confirms what i said with: "Snow will not accumulate ice sheets on the sea"  and therefore is crucial to my theory:


    To not falsify anything with my own translation, i google translated this middle part:

    "Ice ages seem to occur only when there is a larger land mass at least at one geographic pole. Snow has to lie on the continents and not fall into the water, so that a snowpack can form in relatively high latitudes and ice can form over time. Once this is the case, positive ice-albedo feedback occurs due to the high positive albedo values of snow and ice, and further cooling occurs."


  • CO2 was higher in the past

    nyood at 04:18 AM on 7 November, 2019

    @MA Rodger

    (1a) "To present a value for CO2 forcing without providing evidential support is not axiomatic,
    either in the sense of it being self-evident or (probably in the sense you intend) unquestioningly-evident.
    The evidence can be presented should you so wish and, uncontroversially beyond-question, it is correct.

    You yourself present @92 an unsupported evaluation of CO2 forcing, providing a maximum value which appears novel and controversial in the extreme.
    You fail to present any evidential support which in the circumstance is turning this discussion into a pantomime.
    Perhaps you could correct the untenable postion you create for yourself by providing that missing evidence."

    (1a) The evidence that i imagine you would provide, will all result in the question: What is missing? This is manifested in the fact that you will get no exact value for CO2 sensitivity, despite known elemental spectral laws regarding infrared absorption. In other words: We are still estimating with 1,5°C - 4,5°C per doubling (?).

    The theory that CO2 reaches a "saturation" already, is just the most likely aproach to me. However the forcings of HHE/LPC could be even that strong
    that they shrink down all other factors making them neglectable, not "needing" any other explanation to temperature.

    The major evidence i can deliver here is the fact that the so called saturation for each GHG is one of the known unkwons and that there are countless debates
    on this issue, underlining how unsolved this whole matter is.


    "(1b) Your confused statements regarding HHE/LPC appear to contrdict the geographical situation as commonly understood,
    in that the "Land mass" Gondwawa sits static over the "Polar Circle" throughtout this period.
    You need to consider how it is your LPC appears then disappears within this period when the contition you say causes LPC remains unchanging?"

    (1b)  I see no contradiction, in my former post i gave you the 2 links with the continental distribution, matching my theory.(Ordovizium, Silur)

    I see what you are getting at though wih Schwanck slide 11: The pictures with the "paleo glacial reconstruction". They use a static continental distribution here. It is more likely that the continents were merging towards the hirnation. In a larger perspective the continents definetly move  towards the pole, documented by the ordovician with the silurian as a whole. The ice needs to build up and the Boda event interrupted the glaciation process by reducing ice albedo.


    "(2) Your cut-&-paste from the Schwark & Bauersachs slides appears particularly inept as support for your assertion "in fact it doubts CO2 as a driver."
    If you, for instance, examine Slide 11 you will see your assertion is fundamentally contradicted."

    What is contradicted here? Slide 11 shows the Boda event and its CO2 emissions, the CO2 does not matter to me, regarding temperature, the factors that matter are albedo reducing ashes and dust.

    If you are refering to this sentence on page 11: "atmospheric emission of large amounts of CO2 and subsequent climate warming, and.."

    Then i can only tell you that Schwarck are using the neglectable CO2 sensitivity axiomata here. The reason why the Katian doubts ´CO2 as a driver´ is because it marks, with all other epoches preceeding the LPC event, the time where CO2 fails to work as assumed. Where should it show its significant forcing if not here?


    "(3) Here you really do dip into uncomprehensibility. Do note that the Schwark & Bauersachs slides do not ever say CO2
    dropped to present atmospheric levels 400-odd million years ago.
    The statement you misread from Slide 23 says purely that CO2 varied "between 8-16 x PAL and near PAL."
    The value 1500ppm can be taken from their Slide 11."

    (3) Well, it does not matter to me, if you want it can be 1500ppm, i would not consider that close to PAL though. PAL would just makes sense to me since the ordovician

    is compareable to all other LPC events.

    Near Pal makes sense to me because it would reach common glacial CO2 levels. I have not enough knowledge of solubility.

    Near Pal is enough for me to support the theory when it comes to: All equilibrium events and the transitions inbetween happen in the same fashion, despite varying CO levels.

    "(4) If it is not land at the polar circle that creates your LPC condition; if it is ice-covered land,
    you do then reqire to explain the forcing that allows the growth/shrinkage of that ice.
    And in doing so, your theory now lacking the tectonic element, do consider that you are now describing a climate feedback not a climate forcing."

    The factor that you are missing here is indeed a fundamental one. It is the fact that snow will not accumulate ice sheets on the sea.
    The double proof for this is the arctic sea, with Greenland within the polar circle.

    In fact with your misunderstanding here it makes me wonder if continental drift as a time dependet factor is included in the prognostications and not only be representd by the, in itself correctly implemented, ice albedo.

    In other words:Fundamently excluding a long term factor of warming.

  • CO2 was higher in the past

    nyood at 05:28 AM on 5 November, 2019

    "(1) The total climate forcing from 6000ppm CO2 is very roughly 40Wm^-2. There is no evidence
    to suggest that climate was impacted by such forcings (from any source) during the Ordovician."

    (1) The first sentence is axiomaticly using an estimated forcing of CO2 and therefore is a statement, though the consequences you state are true (none).
    I state that CO2 forcing is max 1°C, reaching saturation with roughly PAL levels, pretty much always or already.

    The Second sentence is true, the forcings that Do determine climate Temperature (T) are the two equilibrium forces
    hothouse effect (HHE) and high landmass ratio within polar circles (LPC).
    The faint sun paradox (FSP) underlines the strength and dominance of the terrestial forcings by allowing
    the orrdovician-silurian events, HHE - LPC - HHE, to happen within the same T amplitude of all compareable HHE and LPC events untill today.
    Neglecting CO2 and reducing the FPS or -4% TPI, in its forcings.

    On top of that you devaluate some of your own arguments brought up in the coming sections. According to (1) you do not allow yourself any comparison from there on.


    "(2) According to your cited reference (slides 11 & 14), the period with elevated CO2 significantly above 4000ppm
    coincides with the Katian, a period of warming."

    (2)This sentence has no expressiveness. HHE is happening anyways before and after the LPC.
    The Katian documents the late transition state towards an LPC, in fact it doubts CO2 as a driver.
    The discrepancy between assumed CO2 forcing and T is underlined by the general high CO2 level in the atmosphere, the planet will reach a glaciation from here on, to develop extreme ice shields despite CO2 levels this high. The FPS is solved as mentioned.
    Furthermore forces mentioned in the Schwarck study explain the Katian warming already:
    " Bodaevent:
    Continental Flood Basalt Province.Alternatively to a bolide impact, LIPs have been postulated as warming triggers."

    The forcing here that matters is Ice albedo reduction due to dust and ashes.
    We can see this again when younger impacts and events causie warming rather then cooling.
    An accumulation of dust and ashes at the poles are the result of a rather quickly cleanse of the atmosphere.


    "(3) The period following the Katian sees falling CO2 and falling temperature.
    The period of high glaciation during the Himantian sees CO2 estimates
    dropping to perhaps 1500ppm. Relative to our recent ice ages with 180ppm CO2,
    the Himantian CO2 forcing would thus be perhaps +11Wm^-2 while the relative solar forcing would be -8Wm^-2."

    (3) "dropping to perhaps 1500ppm". The Schwarck study claims PAL up to x6 till x20. Please specify "perhaps"
    and clarify why it is not PAL but minimum PAL x3 according to you. Where are Schwank wrong ?

    Reminding here that the level of CO2 does not matter in the first place unless it is below PAL (max -1°C), using my axioms.

    Again you apply axiomatical values, which are not needed to explain temperatures, you are still using the FSP as a theory support, or to bring it in an equilibrium with
    CO2 forcing, by trying to "ramp up" CO2 to a minimum of 1500ppm. Ironically this opposites many attempts
    that try to lower CO2 to explain why a glaciation happens, despite ~6000ppm before and after the glaciation, in the first place. These views higlight the needs to explain CO2 forcings as assumed (too high).


    "(4) Your assertion @89 is that the major forcing of climate is the tectonic positioning of land over polar regions.
    Yet there was such land over polar regions throughout the Ordovician when these great swings of climate appear suggesting
    the climate was being forced by entirely different mechnisms.

    I would therefore suggest you have failed to provide any support for your assertion "CO2 is no driver at all." "

    (4)This is partly true, as strong as it is the Ice has to build up, which happens very quickly in the hirnation, after the Bodaevent.
    The middle to late ordovician is in transition, the continental drift towards the pole is remarkable.
    Which is documented with the Silurian:



    Furthermore one has to take in account the varying lengths of time periods. The ordovician has been added historicaly,
    it was included in the silurian before, therefore this interesting periods are "staunched".

    Antarctica shows a trend towards having a "drop back" to the south pole, mentioned in the devonian and possible in the jurassic.
    Maybe this happened here too and we need more accurate paleogeorgraphic data.


    Answering two other comments here made by other users:

    89.Moderator response:

    "[PS] This is heading way into sloganeering territory. You are selecting only observations that support your ideas and ignoring completely all others. Science does not operate that like.
    You cannot ignore measured increase in downwelling radiation, conservation of energy, nor explain past climate change with hand-wavy statements that violate physics.
    If you have a theory that can match all observations, simpler and with better precision than current theory and concordant with laws of physics then by all means publish. Meanwhile,
    current climate theory is the one that matches Occams razor. No more half-baked sophistry please."

    My theory already has a better explanation with its radical attempt, that is the whole point. This is not "sloganeering" it is just a very radical attempt so it asks for situations where we have evidence that show CO2 as a significant driver, relating to topic.
    I understand that my radical attempt makes it easy for me but i have to insist on the fairness that i am allowed to show that radical assumptions that i made, make more sense then your axiomatical assumptions.
    There is the inherit problem that we eventualy go off topic but i have to ask you at this point which laws and forcings (radiation, energy conservation) are ignored by me in which way ?
    I ignore factors as far as they allow me, hence ockham.
    I insinuate that your axioms make less sence then mine. Your critisicsm lacks precission at this stage, when it comes to why my radical assumptions are not allowed and where they are not concordant with laws of physics.



    90. Eclectic:

    "Nyood, the importance of CO2 as a driver of climate, is supported by (A) theoretical calculations [Arrhenius and later scientists]; is supported by (B) experimental evidence; is supported by
    (C) observational evidence; and is supported by (D) geological evidence. In other words, the mainstream science developed during the past 200 years.

    The principle of Occam's Razor is a often a helpful guide to thinking : it is not in itself evidence and it is not in itself a method of proof.

    Ockham (or Occam) did not support the cutting off or ignoring of evidence. Newton and Einstein did not ignore evidence. Nyood, why do you choose to ignore evidence?"

    (A) Arrhenius,Planck Feldmann give a frame, it is known that we can not apply CO2 with a clear value (uncertainty). This leads to a Saturation and or Lindzen and therefore inevitable offtopic, as much as i am willing to discuss it.

    (B) same as (A)

    (C) I clame that observational evidence support my theory today: Dramatic CO2 increase with a moderate warming trend. My initial post was rightfully snipped of modern time references as offtopic.

    (D) Geological evidence is the core of the LPC theory.

  • CO2 was higher in the past

    nyood at 02:43 AM on 4 November, 2019

    Moderator Response:

    "[DB] Please re-read the entire post before commenting. As the post notes, CO2 is not the only driver of climate.
    No climate scientist makes any such assertion. So you tilt at windmills of your own building."

    There seems to be a  missunderstanding here, apologies for my bad writing in my initial post if this is the reason for the confusion.

    I do not contest that or if CO2 is a sole climate driver. I state that CO2 is no driver at all.

    So let me try to give a summary here again:

    The theory is radical. The two equilibriums glacial period (high landmass ratio within polar circles,high LPC) vs Hot House Effect (HHE),
    are that dominat, they neglect all other drivers. low LPC will result in a HHE no matter what.
    General backround HHE forcing is so effective, all other factors do not matter, the warming rate is always rapid, the transition is always within 100 mio years.
    The second largest factors that still have significant forcing are all factors that relate to albedo foremost ice albedo (dust, ashes, sea level).

    Following Orckham we have several situations where neglecting CO2 makes way more sense than assuming any significant forcing.

    Ordovician high disparity of CO2 and T. Carboniferus CO2 drop way before temperature (T) drop. Jurassic CO2-T meeting. Cretaceous all time highest discrepancy.

    TempCo2History to

    The situations where an explanation for CO2 is needed to justify its assumed forcings, is simply and higly objected by Orckham`s razorblade principle.

    So politely i have to say dito: Please re-read my initial post.

  • CO2 was higher in the past

    nyood at 05:33 AM on 2 November, 2019

    According to this recent study we have a way more accurate view on this issue now:


    In the Hirnation Event Summary:

    "Massive perturbations of the atmospheric and hydrosphericcarbon cycle occurred with CO2concentration varying between 8-16 x PAL and near PAL over short periods of time." PAL means Present Atmospheric Level.

    This is quite remarkable, it tells us that a glaciation is capable to absorb even CO2 ammounts of 6000ppm. It does not matter how high CO2 Levels are, a glaciation will happen when the following event occurs:

    Sufficent Landmasses within the Polar Circles (LPC).

    Going through all time periods, we can show how decisive landmasses at the polar circles are. Note that the polar circles represent a very narrow area at the north and south borders on these pictures. Greenland todayis a good example as it forms the only northern ice shield, mainly being within the arctic circle, while edging Canada and Russia are not inland iced.

    Cambrian warm period, Landmasses in the Polar Circles (LPC): 0%-10%


    Ordovician hirnantion glacial event antarctic LPC 100%:


    Silurian cold LPC antarctica 90%:


    Devonian warming LPC 10% - 40% :


    Carboniferus glaciation, Continents drop back to the south pole antarctic LPC: 90%-100%


    Permian Cold with late permian transition towards mesozoic Pangea arctic LPC 80% - 100%:


    Triassic warming, antarctic PLC 10%-20%, arctic PLC 70% to 90%. only Southern PLC decisive? Arctic inland ice forming reversed with the jurassic? Triassic north pole contradicton.


    Jurassic, Landmasses moved away from the arctic cycle. arctic LPC 10%-20%. antarctic LPC 5%-10%.


    Cretateous, sea level rise noticeable, deglaciation at its maximum, transition to upcoming glacial period, Antarctica moving south. Antarctic LPC 80%-100%:


    Today, Cenozoic glacial period Antarctica resting at the pole once again. Greenland LPC 10% -20%, Antarctica 90%-100% LPC.

    With an Ockham attempt i want to make 3 main arguments on why CO2 is not needed and not likely to play any thermal role at all:

    1.Faint Sun Paradox,Snowball Earth and the Hot House Equilibrium.

    The faint sun paradox is not a paradox. It is another evidence of how strong the terrestial force Ice Albedo is and therefore again the continental distribution.

    Even with a 25% lesser sun, Oceans occur,hence the term "paradox".While precambrian snowball effects due to a supercontinent at the south pole, demonstrate the lesser sun effect.

    The so called paradox underlines the trumendos forcings of Albedo and it describes the fundamental drive towards a hot house equilibrium whenever the poles are uncovered by land.

    This Basic heating Trend that is strong enough to even compensate the faint sun paradox puts CO2 further away from having any thermal influence. This basic heat trend is documented by all the terminations of glacial epoches and even more so in the precambrian, with a barrier where no more heating seems possible.

    So we keep in mind that we have a Glacial period during the ordovician to the early silurian, with Co2 levels around up to 6000ppm.

    2. Carboniferous CO2 Levels

    The carboniferous marks the point where the flora takes an increased influence on CO2 levels.


    The late devonian till the middle carboniferus show how CO2 is absorbed while temperatur takes ~90 mio years to "follow".The reason temperature goes down is as usual, the continental drift towards the south pole.

    What we eventualy see is a double decline in CO2.

    The jurassic-cretaceous meeting of CO2 and temperature speaks for itself.

    3. Today,GISS and an estimated CO2 sensitivity of 1,5°C

    The uncertenty itself on the CO2 sensitivity after 30 years of research tells us per se that the science is not settled. IPCC on a global warming of <ahref=>1,5°C

    "Past emissions alone are unlikely to raise global-mean temperature to 1.5°C above pre-industrial levels (medium confidence)"

    "1.5°C emission pathways are defined as those that, given current knowledge of the climate response, provide a one- in-two to two-in-three chance of warming either remaining below 1.5°C

    or returning to 1.5°C by around 2100 following an overshoot."

    GISS  actualy does show us a trend towards 1°-1,5°C ~2100 a.d. It is the natural interglacial trend. There is no evidence that our warming period is unique in its rate of warming compared to past medieval epoches

    or to the past 11 Interglacials in our ice cores

    The lowest model called the "russian model"

    What is with Planck and Bolltzmann? my guess is Lüdeckepage19
    and others are right, the saturation is already reached at PAL with 1°C

    Since the Ordovian showed how much CO2 can be absorb in the oceans, acifidication of the ocean  due to human emissions might be the bigger threat. Even though most of the CO2 was embeded in limestone, hence the CO2 "starvation".


  • Climate's changed before

    MA Rodger at 20:08 PM on 28 October, 2019

    TVC15 @795,

    Your denialist runs through quite a complex argument, so probably well rehearsed but it is not very concerned with reality.

    The talk of the decoupling of global temperature & CO2 is probably going back hundreds of millions of years. There is an SkS post on this here (& probably other too) but I would punt the ball back into the denialist's court and ask which era they are talking about. They probably have some ancient denialist graph showing CO2 & temperature less than strongly coupled but addressing specific eras is the way forward, not trying to debunk some bogus lines on a graph scribbled out years ago, (usually with temperature a parody of this Scotese graph).

    The denialist presumably dismisses the tight coupling of CO2 through the last million years of ice ages with their "slight increase that follows a warming period". Then they plunge into the bold assertion that denies temperatures have been increasing over recent decades. If they require it to be "verified" they obviously haven't understood how thermometers work, how calendars work (winters and shorter, summers longer under AGW) and a whole ot more. This is village idiot talk.

    Their final run is in arguing for there being other causes for the temperature increase which is exceptional over thousands of years but that they deny exists. It would probably be better responding that the cause of such an exceptional global temperature change requires a cause, not just a list of mechanisms that impact the climate system. So if they want to invoke rain or humidity or clouds, what has set these off to cause this exceptional warming now?

    One of those they point to as a potential cause is, of course, manmade. CFCs & HCFCs would have been as bad as CO2 at forcing AGW if they hadn't been banned. There is also albedo which could be forced by land-use change as well as cloud (& there are denialists that have argued this as the cause of warming, although measured albedo shows nothing to support such an assertion).

    Their final talk of "questions that ought to be asked" could be another approach to a reply - what questions? Be specific!!

  • Climate's changed before

    Eclectic at 19:02 PM on 28 October, 2019

    TVC15 @795 ,

    I am assuming that you are dealing with a single denialist who tries to bury you under a blathering gush of Gish Gallop.

    IMO, best to challenge him on just a few points of his gush :-

    (A)  Planetary surface temperatures show a good correlation with the *combined* effects of changes in solar output and variations in atmospheric CO2 level.  Examples: look at the cooler/warmer periods of the Ordovician Age and also the Carboniferous Age, as well as the Cenozoic recently.  Sometimes the CO2 rise was caused by the temperature rise, and sometimes (such as the last 150 years) the CO2 rise preceded & caused the temperature rise.

    [to him] "Question: Why are you apparently unaware of all that paleo evidence?"


    (B)  We know the surface temperature is rising, because [i] satellite evidence shows land and sea ice is melting, and [ii] satellite and tide-gauge evidence shows rising sea level, and [iii] thermometers confirm the rising temperature (a rise now of almost 1 degree since reliable general measurements commenced).

    [to him] 'If you cannot understand such basic science, then your "can't feel it" opinion is worth nothing.'


    (C)  The scientists have looked into all sorts of factors that might influence climate (ranging from clouds and cosmic rays, to greenhouse gasses and albedo changes).

    [to him] "If you yourself have discovered a vitally important factor they overlooked, then [i] tell us what it is, and [ii] write to the National Academy of Sciences, and explain to them what morons they all have been for missing such a basic factor, and (iii) start planning how to spend all the Nobel Prize money that you will be awarded from the astounded and delighted Nobel Committee !   .....And good luck with that, Mr Unappreciated Genius."

    (Doubtless he will start shifting goalposts, and/or go into strawman arguments, and/or go into Conspiracy Mode.)


  • Climate's changed before

    TVC15 at 12:56 PM on 28 October, 2019

    Here's some more climate change denier blather I came across today.

    When you are using a complicated explanation to detail why something is happening, or is believed to be happening, you have almost certainly overlooked a much simpler reason for it.

    In the case of CO2, we already know from the fossil record that levels have been much higher in the past and also lower.

    During periods of low atmospheric CO2 levels, surface temperatures have been significantly higher.

    Likewise, during periods of very high CO2, temperatures were cooler than we are experiencing today.

    In fact, the only consistent relationship between CO2 and surface temperature seems to be the slight increase that follows a warming period as the oceans release stored CO2.

    So, when doubling the atmospheric CO2 level results in a claimed surface temperature change that is essentially imperceptible to the senses, the question becomes, how do we know the temperature has actually increased.

    Assuming an increase in surface temperature can be verified (good luck with that), the next question is, is it really caused by elevated CO2 levels and to what degree?

    What other factors are in play and, most importantly, what other factors cannot be measured and their influence accounted for?

    On the issue of cloud cover, NASA essentially punts.

    They admit that past cloud cover was never measured in any meaningful way and that measuring cloud cover, even with the technology available today, is more or less a scientific fool's errant.

    Of course, the problem is that we can't account for the effect of CO2 unless we also account for the effect of cloud cover, then and now.

    I could go into refrigerants in the stratosphere, the albedo effect, rain and humidity and other factors that are clearly ignored by the settled science crowd, but why bother.

    CAGW is a religion dressed up as a pseudo science trying to pass itself off as legitimate science.

    The reason questions that ought to be asked are not asked is because we would have to admit that the data is insufficient, unavailable and probably unknowable.

    There are so much illogical claims here I don't know where to start!

  • Tipping Points: Could the climate collapse?

    Doug Bostrom at 07:43 AM on 18 October, 2019

    OK that's an arguably fair point, Mark. 

    Adam mentions permafrost loss and hence CH4 emissions, loss of albedo from reduced ice cover, and loss of forest productivity and the CO2 capture associated with that. 

    Those are three positive feedbacks which (we're told by experts) may plausibly end up being self-driving and self-cementing.

    Now, it's not Adam's intention or style to inform readers by reciting facts and figures; those are available elsewhere. His intention and style is to build audience engagement, clearly with the objective of conveying a very broad-brush sense of the topics he's covering and presumably igniting some curiosity and concern about the overall problem of climate change. 

    But Adam might well include a list of references for the concepts he treats, as part of the content at the end of his pieces. 

    Why not write him and suggest that? 

  • Water vapor is the most powerful greenhouse gas

    Eclectic at 09:32 AM on 15 October, 2019

    JamesKL , I am not clear whether you are meaning average temperature for daytime, for nighttime, or for a strict average over the 24 hour day.  Then there are the monthly or seasonal averages (or for "annual average" ~ which is almost a meaningless concept for temperate regions).

    Speaking generally, deserts are "pale" (high albedo = high reflection of sunlight energy) . . . and rainforests are dark, low albedo regions, which absorb more sunlight energy ~ nevertheless much of their temperature difference comes from the cooling effect of evaporation from vegetation. And for deserts at night, the dryness of the land & air means more heat is lost to space.

    Thermometer temperatures are one thing.  But humans' sensation of regional temperature will be perceived according to the extremes of daytime highs and overnight lows, and we tend not to notice those periods when it's "comfortable".  As you know, a high-humidity "hot" day (or night) will be felt as hotter.

    I would imagine that the town of Adrar is quite pleasant, part of each day at least!  Except when the weather produces heat wave conditions

  • How the Greenland ice sheet fared in 2019

    sgbotsford at 00:57 AM on 11 October, 2019

    @william In #6:  

    You could also get increased snow too however.  Some years ago, there was a pre-computer model of ice age triggering that was based on an open arctic ocean.  

    * Increased evaporation led to increased snow fall on surrounding land.

    * Ungava penninsula has later springs and earlier falls.

    * Increased albedo makes Ungava area cooler.

    * Two randomly cooler summers in a row result in not all the snow melting.

    * Because ground is pre chilled, snowfall accumulates faster.  

    * Cold air moving from the snowfield to surrounding area prepares that area for snow pack.

    At the time they figured a permanent snowfield could advance at about 200 km per year.

    No idea if this notion is still credible.

    But:  An arctic ocean will evaporate whenever it's open — slower winter, as I assume at least pan ice will form.  But if the arctic is open while greenland is still 2 miles thick (and high) then soggy arctic air will cool and drop lots of snow.  


    If the latent heat comes from the formation of dew/frost, then your figures are correct.  But it may form in the air, which means it's heat that ends up being radiated to space, no?  If it comes down as snow, it melts nothing.  If it comes down as rain, it melts some ice depending on the rain temperature.

  • Climate's changed before

    MA Rodger at 18:31 PM on 24 September, 2019

    TVC15 @776,

    The denialist asks about the features of two different times and asks what is different today.

    20,000 years ago was the maximum glaciation of the last ice age, this the result of reduced solar radiation for the high-latitude Northern summers which 100,000 years ago triggered an increase in the amount of ice-covered land/ocean in high Northern latitudes. The level of ice was amplified by the increased albedo of the ice reflecting away greater levels of solar radiation and by the reduced GHGs (CO2 & methane) caused by the cooling global climate having a net draw-down of such gases. Thus we find the Laurentide & Cordilleran ice sheets covering mainly Canada and beyond, extending to cover the sites of today's Great Lakes. (The map below ignores changing coast lines.) It thus requires the Laurentide Ice Sheet to melt considerably before the Great Lakes can exist, their formation reportedly beginning 14,000 years ago.

    Ice age N America

    We now leap forward to a time when the Cordilleran ice sheet has long gone. Over recent times the dynamics of glaciers is not always determined by local temperature. A sea-terminating glacier will likely spend most of its days slowing advancing and then, becoming unstable, undergo a short period of rapid retreat. And reduced/increased snowfall can cause a glacier to shrink/expand.

    So is there evidence that "Alaskan Glaciers started receding big time around 1750 to 1900"? Solomina et al (2016) who, in an analysis of global glaciers over the last two millenia, examine land-terminated glaciers in Alaska and see no sign of it. Their Fig 2 shows a GEI index indicating a fluctuation in local glacier size which peaked at about 1880AD. This would explain a "receding big time around ... 1900" but not the earlier 1750 date. Other research may give differing timings but it seems unlikely that there is any proper support for a 1750 to 1900 date. Can the denialist provide support for this bold assertion of his?

    And "why is now any different"? The unprecidented global rise in temperatures will impact glaciers globally, including Alaska.

  • CO2 effect is saturated

    scaddenp at 19:55 PM on 16 September, 2019

    The straight radiative balance (ie doubling CO2 gives you an extra 4w/m2 of surface irradation) would only raise temperatures 1.1C. It is the feedbacks that lift this to around 3C, in part from increased water vapour as well as albedo and clouds.

  • The North Atlantic ocean current, which warms northern Europe, may be slowing

    Human 2932847 at 16:33 PM on 29 August, 2019

    Hmm, well, that's Columbia university Earth Institute saying the effect of the Gulf Stream is way overestimated. If you disagree you could email and chew it over with them.

    I would have thought that ice caps over Europe (and America) affect a lot of things like wind, ocean currents, albedo etc. There would be no North Sea or Baltic. Your link says that there was huge amounts of fresh water released from the American ice cap, more than from Greenland, but that wouldn't be available now. There would be different solar insolation - what else ? It just seems like a very different context to the current one.

    They say

    The determinants of North Atlantic regional climates
    We showed that there are three processes that need to be evaluated:

    • The ocean absorbs heat in summer and releases it in winter. Regions that are downwind of oceans in winter will have mild climates. This process does not require ocean currents or ocean heat transport.

    • The atmosphere moves heat poleward and warm climates where the heat converges. In additions, the waviness in the atmospheric flow creates warm climates where the air flows poleward and cold climates where it flows equatorward.

    • The ocean moves heat poleward and will warm climates where it releases heat and the atmosphere picks it up and moves it onto land.

    I don't know anything about the middle one - but the first and third points must be affected by ice cap conditions over sea and land - of which there was more in the past.

  • Medieval Warm Period was warmer

    scaddenp at 08:10 AM on 27 August, 2019

    yes. Where no temperature measurements exist, then proxies are all you have.

    Dont let a denier take you down the path of believing that climate theory depending on paleoclimate studies. Paleoclimate studies are useful testing grounds - if our current understanding of climate cannot reproduce measurements of temperature given the uncertaintites in the temperature measurement and our understanding of the forcings operating at the time, then the theory would be in trouble. Not the case. Paleoclimate is also useful in constraining climate sensitivity. However, uncertainties in estimating solar output, aerosols, albedo and temperature all create significant limits compared to analysing the physics of the climate system today.

  • CO2 lags temperature

    scaddenp at 08:08 AM on 14 August, 2019

    "Great question. Also an intellegent question. It's something that many Climate Scientists have tried to brush off with a "yes, but CO2 then becomes the forcing agent" as if autocorrelation is only done at the beginning of each interglacial phase. It isn't. It's done over the entire time series, including when CO2 is suppose to become the forcing factor."

    Let's break this down. Firstly, do you accept that glacial cycle is orbitally forced? Further discussion makes no sense if this is not the case.

    Assuming you accept orbital forcing, how do you explain why SH glaciation is synchronous with NH (since orbital forcing is anti-phased). Its easy if you accept known physics (GHE included) but you apparently want to deny that increasing CO2 will warm the planet.

    Secondly, how about linking to some more actual detail about your "autocorrelation" stuff. I dont get your point and I certainly not clear to me what you think you are proving. The relationship between T and CO2 is still somewhat unconstrained but is clearly non-linear and involves multiple mechanisms operating on scales from years to millenia.

    What is the basis for your understanding of "their ever decreasing estimates of how much CO2 impact climate". I certainly do not get that from successive IPCC reports.

    You seem to be implying that papers on direct observation were arguments from correlation. This is not the case. The arguments in those are of the form, "fundimental physics allows us to predict what observations done by this method would show. Let compare model results with observation".

    So from this, you compute how much much the radiation at the surface will change with GHG concentration change - and measure it. You look at how GHG changes would change the spectrum of outgoing or incoming radiation - and measure them. That is what those papers do. Hansen and Sato compute forcing from change in GHG using ice core bubbles as proxy for atmospheric concentration, and compute the change in albedo based on sealevel etc, and finally the global solar irradiation change from milankovitch. Climate theory would expect icecore temperature to be related to that forcing calculation extremely closely and that is what is observed. A failure to observe that would be evidence against.

    Can I ask whether you accept Planck Law? ie, if irradiation of surface increases, then it temperature must rise.

    Finally, climate change at present appears to be forced by GHG change. The feedback mechanisms that apply during ice ages wont cut in any significant way for 100s of years. The natural system is still moping up about half of our emissions which make 616 invalid (actually so many issues with this, its hard to know where to start. You need 30 year averages remove the internally variability, especially ENSO.)

  • 'No doubt left' about scientific consensus on global warming, say experts

    Bob Loblaw at 11:31 AM on 31 July, 2019

    As for surface changes, one of the earliest papers I know of is:

    Anthropogenic Albedo Changes and the Earth's Climate

    By Carl Sagan, Owen B. Toon, James B. Pollack

    Science21 Dec 1979 : 1363-1368

    Link to origfinal source is here:

    but the full text requires an account. Google Scholar will point you to freely-available copies.

    Short version: climatologists have been aware that surface changes can affect climate for at least 40 years.

    P.S. Don't forget to look at the IPPC 1990 report, too...

  • How could global warming accelerate if CO2 is 'logarithmic'?

    scaddenp at 08:31 AM on 30 July, 2019

    richieb1234 - while the Stephan-Boltzmann law gives you relation between radiative power to 4 power of temperate (so the doubling CO2 would raise temp by 1.1C), it is less useful than you might think for estimating actual surface temperature. You cannot raise (or lower) temperature without other feedbacks coming in. These operate on very wide timescales from very fast (water vapour increase), through decadal scale of albedo change from less ice, to century/millenia feedbacks in carbon cycle. Add in the complexity of cloud feedbacks (both +ve and -ve), and you get the wide range of estimates on climate sensitivity.

  • Michaels Misrepresents Nordhaus and Scientific Evidence in General

    Daniel Bailey at 02:47 AM on 25 July, 2019

    "At what degree does the Arctic lose it's ice during the summer months?

    Because I can assure you that once that happens, there will be no stopping Global Warming.
    Does it happen at 2°C or less?

    Fortunately, scientists have looked into the effects of an ice-free Arctic.

    Pistone et al 2019 - Radiative Heating of an Ice‐free Arctic Ocean

    "Here we use satellite observations to estimate the amount of solar energy that would be added in the worstcase scenario of a complete disappearance of Arctic sea ice throughout the sunlit part of the year. Assuming constant cloudiness, we calculate a global radiative heating of 0.71 W/m2 relative to the 1979 baseline state. This is equivalent to the effect of one trillion tons of CO2 emissions. These results suggest that the additional heating due to complete Arctic sea ice loss would hasten global warming by an estimated 25 years."


    1. "Of the 0.71 W/m2 of globally-averaged heating, 0.21 W/m2 is estimated to have already occurred between 1979 and 2016. Approximately half (0.11 W/m2) of this realized heating occurred during the CERES observational record (2000-2016), with the other half occurring between 1979 and 1999 as estimated based on the observed relationship between satellite-derived sea ice concentration and albedo."

    2. "we cannot exclude the extreme possibility that the Arctic could become annually ice-free during the coming decades"

    3. "even in the presence of an extreme negative cloud feedback, the global heating due to the complete disappearance of the Arctic sea ice would still be nearly double the already-observed heating due to the current level of ice loss"

    4. "The present study focuses on the additional radiative heating from the complete loss of Arctic sea ice, but it does not estimate the amount of global warming that would be associated with this level of ice loss"

    5. "even under conditions in which the Arctic Ocean becomes ice-free only in September, the additional radiative heating may likely be driven largely by the associated midsummer sea ice loss"

    6. Arctic sea ice will continue to re-form in Arctic winter for the foreseeable future even after the loss of summer sea ice (the sun-lit portion of the year the paper primarily deals with)

    Money section:

    "This heating of 0.71 W/m2 is approximately equivalent to emitting one trillion tons of CO2 into the atmosphere. As of 2016, an estimated 2.4 trillion tons of CO2 have been emitted since the preindustrial period due to both fossil fuel combustion (1.54 trillion tons) and land use changes (0.82 trillion tons), with an additional 40 billion tons of CO2 per year emitted from these sources during 2007-2016 (Le Quere et al., 2018). Thus, the additional warming due to the complete loss of Arctic sea ice would be equivalent to 25 years of global CO2 emissions at the current rate.

    This implies that if the Arctic sea ice were to disappear much more rapidly than in current climate model projections, it would drastically shorten the time available to adapt to climate changes and the time for achieving carbon neutrality."

  • 2019 SkS Weekly Climate Change & Global Warming News Roundup #27

    scaddenp at 08:06 AM on 24 July, 2019

    I would add two things.

    1/ The actual surface temperature year to year is strongly affected by internal variation. ie heat sloshing around in a wet, unevenly heated planet. ENSO is the dominant component of this. For this reason, climate is defined as 30 year average. Arguably, Ocean Heat Content is a better metric than surface because most of the heat goes into the ocean and the total energy varies less (the little wobbles are ocean/atmosphere exchange). However, we have only been able to measure this with confidence relatively recently.

    2/ Climate changes in response to net forcing. Changes GHGs are only one element (though the dominant one in recent history), but aerosols either man made or from volcanoes are also important (especially mid 20th century, and after really big tropical volcano eruptions). Changes in solar input and albedo are the other important inputs into calculation of forcings.

  • Where to find big ideas for addressing climate change

    RedBaron at 11:13 AM on 9 July, 2019

    @1 bjchip,

    Yes, Savory has a big idea with even more potential than the other "Big Ideas" mentioned in this article. It is also included in a more limited way as part of project drawdown as well. So there is that as well.

    In my opinion there is no solution to AGW that doesn't include this at least in part, because it is the only current technology both scale-able enough and also fiscally sound that humans have available in their tool kit at the moment.

    Otherwise the evidence suggests even 100% elimination of fossil fuels won't be enough and the legacy carbon will continue to heat the surface for decades at minimum and maybe even 100's of years. We have about .5c thermal inertia of the oceans: climate inertia; and we also have 1.5c loss of albedo from melting ice as a feed back: 
    Hansen and Sato Estimate Climate Sensitivity from Earth's History, and likely another 1c from various other reinforcing feedbacks like methane releases from melting permafrost and vegetative die off of areas due to climate zones moving faster than biomes can adjust.

    So somewhere around 1.5-3.0 c additional warming if emissions went to zero today.

    The only technology capable of reversing this is in fact what Savory proposed, and is indeed beginning to do on 10's of millions of acreas already through his worldwide network he set up.  


More than 100 comments found. Only the most recent 100 have been displayed.

The Consensus Project Website


(free to republish)

© Copyright 2021 John Cook
Home | Links | Translations | About Us | Privacy | Contact Us