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Timothy Chase at 12:51 PM on 7 March 2011Blaming the Pacific Decadal Oscillation
I had written in 56:We can't explain the warm interglacials and ice ages without the amplification due to carbon dioxide (which is released by the oceans when they warm like a warming soda losing its fizz but absorbed when the oceans cool), ice sheets (due to their melting and growth) and water vapor feedback.
RW1 responded in 61:Sure we can. The glacial and interglacial periods in between are driven by changes in the Earth's orbit around the Sun, which in turn changes the distribution of the incoming solar energy immensely. This is enough to overcome what appears to be a very strong net negative feedback operating on the system. CO2 lags or follows these cycles - it does not coincide or precede them.
CO2 lags warming by no more than 1000 years, likely as the deep ocean gives up carbon. And when I stated that carbon dioxide (under these circumstances) is a feedback that implied a lag of sorts. The warming from a glacial to interglacial takes several thousand years. Therefore the carbon dioxide actually coincides with much of the warming. Which is why the curves appear to be almost on top of one-another. Looking at just the warming due to solar insolation you can't explain the saw tooth structure of the temperature and CO2 trendlines. Things warm rapidly, with the warming period appearing to be perhaps 7000 or 8000 years. But the cooling takes perhaps 100,000 years. Orbital forcings can't explain why this asymmetric pattern appears time and time again. But the rapid decay and slow growth of ice sheets as well as the rapid degassing but slow absorption of carbon dioxide by the oceans and ultimately it minearlization can. For the sawtooth structure please see Figure 1 here: CO2 lags temperature - what does it mean? http://www.skepticalscience.com/co2-lags-temperature-intermediate.htm In the review article: C. Lorius (13 Sept 1990) The ice-core record: climate sensitivity and future greenhouse warming, Nature, Vol 347 ... Hansen and coauthors state:The orbital forcing is, however, relatively weak when considered on an annual globally averaged basis (the total insolation received by Earth has varied by 0.7 W m-2 over the past 160 kyr). The amplification of this forcing, the observed dominant 100-kyr cycle and the synchronized termination of the main glaciations and their similar amplitude in the Northern and Southern Hemispheres cannot easily be explained despite developments including the nonlinear response to ice sheets to orbital forcing.
Solar forcing is weak. You can't even explain the extent to which warming to place even when you include the nonlinear response of ice sheets. And you can't explain the synchronicity of the warming of both hemispheres. Both GCM studies and multivariate studies of paleoclimate data suggest that roughly 40% of the warming of the Antarctic from glacial to interglacial was due to the increase in CO2 from 200 to 300 ppmv. (See page 144.) Furthermore, while recognizing that orbital forcing was responsible for the Milankovitch cycles, they predicted that through the analysis of upcoming ice core samples it would be possible to identify the lag time between the initial warming and the rise in carbon dioxide. Please see:This objective is part of the GRIP (Greenland Ice Core Project) and GISP II (Greenland Ice Sheet Project) now being conducted in north central Greenland by Eurpopean and American scientists. These dirllings are expected to reach the bedrock (ice thickness is 3.2 km) in 1992 and to cover the last climate cycle and hopefully more. These cores will allow further documentation of the rapid climate changes discussed here. With a snow accumulation higher than at Vostok they should also allow a better determination of the relative timing (phase lag) of climate and greenhouse forcing. pg.145
But just as importantly there were times when carbon dioxide rose first. The ice cores from Greenland and Antarctica have taken us back the better part of a million years now. During this time temperature always seems to rise first. However, if you look back further in the case of supervolcanoes and their flood basalt eruptions carbon dioxide rose first, then temperature. Examples of where continental and submarine supervolcanoes gave rise to Large Igneous Provinces resulting in mass extinction include: 55 Mya, Paleocene-Eocene Thermal Maximum – North Atlantic Basalts 65 Mya, end-Cretaceous event resulting from a supervolcano that gave rise to the Deccan basalts in India as it collided with Asia at the time of the formation of the Himalayas 183 Mya, Toracian Turnover (a lesser warming and extinction event in the Early Jurassic period) – Karoo Basalts (Africa) 201 Mya, End Triassic Extinction – Central Atlantic Magmatic Province 251 Mya, Permian-Triassic Extinction that resulted from a supervolcano that left behind the Siberian basalts during the breakup of Pangaea. 360-375 Mya, Late Devonian Extinction – Viluy Traps (Eastern Siberia, more tentative according to Rampino below) For a more extensive list, please see: Vincent E. Courtillot and Paul R. Renne (2003) On the ages of flood basalt events, C. R. Geoscience 335, 113–140 For a recent commentary: Michael R. Rampino (April 13, 2010) Mass extinctions of life and catastrophic flood basalt volcanism, PNAS, vol. 107, no. 15, pp. 6555-6556 Here is recent study showing that the eruption of the Central Atlantic Magmatic Province occured simultaneously with the end Triassic Extinction 201 Mya: Jessica H. Whiteside (April 13, 2010) Compound-specific carbon isotopes from Earth's largest flood basalt eruptions directly linked to the end-Triassic mass extinction, PNAS, vol. 107, no. 15, pp 6721-6725 In recent times temperature generally rose first. But if you look further back, in some cases carbon dioxide rose first, then temperature. And those times that carbon dioxide rose first are strongly associated with sudden changes in climate and the resulting major and minor extinction events. -
RW1 at 12:17 PM on 7 March 2011Blaming the Pacific Decadal Oscillation
Philippe (RE: 65), "I don't see how your short paragraph argues against the CO2 feedback in interglacials. The adverb "immensely" used in reference to the change in insolation distribution is more rethorical than accurate." How do you figure? Does the angle of insolation and subsequent distribution not change significantly? "Nonetheless, the fact that CO2 changes follow the initial deglaciation induced by orbital changes does nothing to indicate CO2 does not or can not act as a positive feedback. Furthermore, the radiative properties of CO2 are such that it is physically impossible for the gas to not act as a positive feedback at some level." Yes, the physics do suggest at least some positive feedback effect is likely, but I think the data strongly suggest it's negligible and the main forces driving the changes are the orbit combined with the ebb and flow of surface ice, especially since temperatures at the end of the interglacials continue to fall significantly even as CO2 remains relatively high. "Paleo data show CO2 levels coinciding with interglacials and following the initial degalciation. It also shows temp increasing to a level that insolation changes alone would not explain. If you want to argue against that, make an argument that is at least logical. The fact that CO2 changes follow the deglaciation by itself is not enough to prevent it from acting as a feedback. The Paleo data also shows previous interglacials, with lower CO2 levels, being warmer than the one were are in now. This is a strong indication that CO2 is not a significant driver of these cycles. If it were, temperatures would be even warmer than previous interglacials - not cooler.
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Charlie A at 12:09 PM on 7 March 2011Blaming the Pacific Decadal Oscillation
#47 RW1 says "The bottom line, for me at least, is net positive feedback is an extraordinary claim that requires extraordinary proof,... " Net positive feedback in climate science is not the same as net positive feedback in most other fields. The terminology in climate science are a bit messed up in that a "net positive" feedback per standard climate science convention would still be a net NEGATIVE feedback as long as the positive feedback is less than the increased blackbody radiation from the increased temperature of the earth. Or to put it another way, the increased blackbody radiation from a warming earth is not included in the feedback sums to determine whether there is postive or negative feedback. -
Bern at 11:54 AM on 7 March 2011The Climate Show Episode 8: Kevin Trenberth
zinfan94 - I understand the majority of that CO2 absorption is going into the oceans. As warming continues, that particular sink will decline, and possibly reverse, so we may not be able to rely on natural processes to remove excess CO2 from the atmosphere. Although the required scale of industrial plants capable of sequestering billions of tons of CO2 each year is pretty concerning... are there industrial processes capable of cracking that CO2 back into C + O2? It'd be a lot easier to sequester solid briquettes of C (plenty of open cut mines to backfill, or even dump them on the seabed) rather than liquid or gaseous CO2... -
Bern at 11:50 AM on 7 March 2011The Climate Show Episode 8: Kevin Trenberth
I've really gotta set aside the time to watch these... Although 70 spare minutes is hard to come by with a 5-month-old in the house!Response: I'm learning to find little pockets of time to listen to the long TCS episodes - while exercising, driving, doing household chores, the mowing, etc. There's just so much info packed in an hour or so, it's worth the trouble to find a way to shoehorn it into the schedule. -
KR at 11:49 AM on 7 March 2011Icing the Medieval Warm Period
Gilles - The second graphic Tom Curtis shows here is the result of multiple model runs using various forcings. As per the caption, the blue bar represents the 2-sigma variation range around model runs that do not include anthropogenic forcings (but do include insolation, volcanic aerosols, orbital effects, etc.), the red bar represents the variation range around models run with our forcings, and the black line is the actual temperature record. These are models shown to have considerable agreement with historic temperatures (including some pre-industrials) using recorded forcings. The point made in this graphic is that we have some idea of how forcings drive temperatures, and that we cannot account for current temperature rise without the anthropogenic contribution as part of the physics. -
zinfan94 at 11:49 AM on 7 March 2011The Climate Show Episode 8: Kevin Trenberth
Gareth messed up the information on carbon balance when discussing the carbon that will be released from melting permafrost. We don't have to "suck carbon out of the atmosphere" to reduce carbon dioxide concentrations in the atmosphere. The various carbon sinks, the oceans, soils, and vegetation, are currently taking over half of the carbon from fossil fuels and deforestation... If we reduce fossil fuel emissions 60-80%, then carbon dioxide concentrations in the atmosphere will begin to drop. We do NOT have to begin removing carbon dioxide directly from the atmosphere using a human installed process to get declines in CO2 concentrations. We do not have to get to below zero fossil fuel carbon emissions, as he stated later in this Climate Show.Moderator Response: [Daniel Bailey] Tom Wigley covered that very topic over at Brave New Climate, here. Note that in Tom's study, global zero CO2 emissions are not achieved until 2050, but then held there indefinitely once achieved. Also, AR4 assumptions are used for Ice Sheet melt (and thus are obsolete). And finally note that, even holding global emissions to zero, it will then take over 100 years for concentration levels to drop below 350 (considered the "safe" maximum limit). -
Philippe Chantreau at 11:45 AM on 7 March 2011Blaming the Pacific Decadal Oscillation
RW1 @ 61. I don't see how your short paragraph argues against the CO2 feedback in interglacials. The adverb "immensely" used in reference to the change in insolation distribution is more rethorical than accurate. Nonetheless, the fact that CO2 changes follow the initial deglaciation induced by orbital changes does nothing to indicate CO2 does not or can not act as a positive feedback. Furthermore, the radiative properties of CO2 are such that it is physically impossible for the gas to not act as a positive feedback at some level. Paleo data show CO2 levels coinciding with interglacials and following the initial degalciation. It also shows temp increasing to a level that insolation changes alone would not explain. If you want to argue against that, make an argument that is at least logical. The fact that CO2 changes follow the deglaciation by itself is not enough to prevent it from acting as a feedback. -
KR at 11:38 AM on 7 March 2011Blaming the Pacific Decadal Oscillation
RW1 - My point was that precipitation is not, repeat, not a pathway of energy back to the surface. That energy of evaporation is left in the atmosphere, representing part of the energy transfer to the atmosphere (convection, latent heat, and IR, in increasing order). Latent heat loss certainly cools the surface. Some of that energy returns to the surface as backradiation (not precipitation), some is radiated out to space. -
adelady at 11:27 AM on 7 March 2011Icing the Medieval Warm Period
Gilles "I see a shift in the 1950's, and your glaciers has experienced already most of their melting at this date. Aren't you distorting mere facts ? " No. I see this little factoid as a possible signal of other things. That initial leaning into a downward slope on the glacier mass balance trend indicates 2 possibilities. Firstly, solar irradiance was higher for much of that period and that might just have been a blip in a long term trend if other things had not changed. Secondly, and more importantly from my point of view, I have a lurking suspicion that much of the warming-that-didn't-show-up-until-the-70s went into a couple of dark corners that seemed insignificant at the time. Night-time minimum temperatures. Ice melt. And that ice melt would have predominated in land terminating glaciers rather than those supported by sheets of sea ice buffered by the oceans. Even where the edges of those ice sheets were retreating, however erratically, they didn't lose enough to damage the glaciers at their landward edge. It certainly wasn't large enough or fast enough to sound the kind of alarm bells we're now seeing for Arctic sea ice. But I think there's almost enough data around for there to be a century long trend when we look at the right indicators. -
muoncounter at 11:17 AM on 7 March 2011Icing the Medieval Warm Period
G: "I don't see anything like that in your curve." We are discussing the bottom graph here. Is there not a conspicuous rise from 1930-mid 40s? Is the northern hemisphere 1970s low present in this graph? Please avoid accusations of factual distortion -- that is a violation of the Comments Policy. -
RW1 at 11:08 AM on 7 March 2011Blaming the Pacific Decadal Oscillation
KR, "But the point remains - precipitation has less energy than water vapor, and the precipitation cycle is a major pathway of energy into the atmosphere. Not back to the surface. And calculating global precipitation (and the energy moved in that fashion) is how Trenberth obtains the 78 W/m^2 latent heat figure in his energy balance diagrams." Yes, but precipitation is also still a considerably large pathway of energy back to the surface, and any latent heat energy removed from the surface that isn't returned to the surface in equal amount will have a cooling effect on the surface, reducing surface emitted radiation; thus equally offsetting any latent heat energy radiated into the atmosphere that ultimately escapes out to space. -
Gilles at 10:58 AM on 7 March 2011Icing the Medieval Warm Period
" New Zealand temperatures, after being flat for the first part of the 20th century started to rise in the 1930's" Really, I don't see anything like that in your curve. Why do you say that temperatures started to rise in 1930 ? I see a shift in the 1950's, and your glaciers has experienced already most of their melting at this date. Aren't you distorting mere facts ? -
Gilles at 10:53 AM on 7 March 2011Icing the Medieval Warm Period
" 1) The temperature does not fall outside the confidence interval of combined anthropogenic and natural forcings over the same period;" First you should recognize that it is not the "temperatures" but the "anomalies" with respect to the first half of the XXth century - this by no means surprising that ANY anomaly computed with respect to the same period are comparable, irrespective of the model - the opposite would be surprising ! so the agreement in the first part is of low significance. " 2) The combined anthropogenic and natural forcings predict a higher temperatures than natural forcings alone (thus shown the anthropogenic forcings to be significant); and" actually the graphics has always been unclear for me, but may be you can explain me : is the blue curve a "best fit" obtainable without anthropic component ? or is it a "best fit" WITH anthropic component, after substraction of the anthropic component? that's quite different. If you optimize the model with an anthropic component, and AFTER substract anything , you are sure that the result is worsened. But that doesn't prove that another equally good fit could be obtained with other hypothesis. " 3) The temperature tends to lie near the center of the anthropogenic and natural forcings, but on the extreme limit of the confidence interval of natural forcings alone." see above. How "natural forcings alone" have been adjusted ? " Once you accept these 6 facts, you will find you no longer need to distort science to accommodate your world view." I will not accept these 6 facts before having a clear answer to the previous questions .... -
KR at 10:48 AM on 7 March 2011Blaming the Pacific Decadal Oscillation
johnd - Evaporated water carries heat into the upper atmosphere, where condensation releases heat to the cooler air, warming it. The resulting precipitation has less energy, or it would remain vapor. Energy thus transferred to the atmosphere is then radiated or convected away. This heat of condensation powers thunderstorms and hurricanes - heating the atmosphere, causing updrafts that drag moist air up to where it condenses, releasing more heat, and so on... The energy can then get radiated out to space (partially), or radiated back to the surface (again, partially). But the point remains - precipitation has less energy than water vapor, and the precipitation cycle is a major pathway of energy into the atmosphere. Not back to the surface. And calculating global precipitation (and the energy moved in that fashion) is how Trenberth obtains the 78 W/m^2 latent heat figure in his energy balance diagrams. --- I would suggest taking clouds to one of the cloud feedback threads. -
RW1 at 10:39 AM on 7 March 2011Blaming the Pacific Decadal Oscillation
Timothy Chase (RE: 56), "We can't explain the warm interglacials and ice ages without the amplification due to carbon dioxide (which is released by the oceans when they warm like a warming soda losing its fizz but absorbed when the oceans cool), ice sheets (due to their melting and growth) and water vapor feedback." Sure we can. The glacial and interglacial periods in between are driven by changes in the Earth's orbit around the Sun, which in turn changes the distribution of the incoming solar energy immensely. This is enough to overcome what appears to be a very strong net negative feedback operating on the system. CO2 lags or follows these cycles - it does not coincide or precede them. -
Timothy Chase at 10:37 AM on 7 March 2011Blaming the Pacific Decadal Oscillation
RW1 quotes RickG then writes in 51:"As for clouds, those with small water droplets (lighter clouds) tend to reflect light while those with larger water droplets (darker clouds) tend to absorb more light. Am I wrong?" I'm not sure.
It's pretty obvious in the visible part of the spectrum. Rain clouds -- where the drops are coalescing to form larger drops that are eventually heavy enough to fall -- are darker than the light fluffy clouds. Dark clouds tend to produce especially downpours. However, clouds per se are close to being perfect black bodies in the infrared spectrum. This doesn't matter much if the clouds are close to the surface since they will be roughly the same temperature as the ground and emit radiation at roughly the same rate that they absorb it. But in accordance with Kirchoff's law high altitude clouds absorb radiation independently of their temperature but emit radiation proportional to their temperature taken to the fourth power. So increasing high altitude clouds will tend to warm the climate system as they reduce the rate at which energy escapes to space. As they warm they reduce the rate at which heat escapes from successively lower layers as they decrease the temperature differential until those lower layers warm like the layers above them. Given an enhanced greenhouse effect, whether it is due to higher levels of greenhouse gases or high altitude clouds, an equilibrium will eventually be reached. At some point the rate at which radiation leaves the climate system will equal the rate at which radiation enters the climate system. However the altitude that radiation escapes from will be higher. The greenhouse gases and clouds involved will have to warm in order to radiate energy to space the same rate as the greenhouse gases and clouds at the lower altitudes did before. After the equilibrium has been reestablished the lapse rate -- rate at which temperature falls with increasing altitude -- will be roughly the same. And given the warming of the higher altitudes this will imply a warmer surface. -
RW1 at 10:23 AM on 7 March 2011Blaming the Pacific Decadal Oscillation
Timothy Chase (RE: 56), ""... especially since solar energy is not amplified to anywhere near such an extent." It is amplified to roughly the same extent." How do you figure? 239 W/m^2 of post albedo solar energy becomes 390 W/m^2 at the surface (390/239 = 1.6), where as 3.7 W/m^2 from 2xCO2 becomes 16.6 W/m^2 at the surface (16.6/3.7 = 4.5). If this much amplification is within the systems boundaries, why doesn't it take about 1075 W/m^2 at the surface to offset the 239 W/m^2 coming in from the Sun (1075/239 = 4.5)??? -
RW1 at 10:14 AM on 7 March 2011Blaming the Pacific Decadal Oscillation
johnd (RE: 54), "The only way to determine the bottom line of the process would be to measure the amount of heat being liberated from the surface by evaporation against the amount of heat that is returned to the surface by rain." Plus the amount of incrementally reflected sunlight from clouds. According to Trenberth 2009, the total reflectivity of clouds is about 79 W/m^2, and the total reflectivity of the surface is about 23 W/m^2. Clouds reflect away over 3 times as much incoming solar energy as the surface for a loss of of about 56 W/m^2 for each additional m^2 of cloud cover. However, the clear sky has an average transmittance of 40 W/m^2 and the cloudy sky has an average transmittance of 30 W/m^2 - making the amount of incremental surface power trapped per each additional m^2 of cloud cover 10 W/m^2. Thus, according to Trenberth's numbers at least, each additional m^2 of cloud cover results in a net loss of about 46 W/m^2, which is quite a bit. -
johnd at 10:12 AM on 7 March 2011Blaming the Pacific Decadal Oscillation
Timothy Chase at 09:57 AM, regarding your comment "El Nino temperatures go up due to the energy that is released into the atmosphere. Then temperatures go down." The energy released into the atmosphere then goes where? Having come from the oceans in the first place it is unlikely to all have gone back there again otherwise conditions would be such that a repeat El-Nino would occur. With energy being released from the oceans by an El-Nino, would more CO2 be sunk as a result? -
Timothy Chase at 09:57 AM on 7 March 2011Blaming the Pacific Decadal Oscillation
RW1 wrote in 47:All I'm saying is if natural oscillations (variations) can cause up to 0.5 C of temperature change in one year, why couldn't natural forces cause most of the 0.6 C of warming over the whole of 20th century?
I believe the subject of this post is the climate oscillation known as the Pacific Decadal Oscillation. Climate oscillations like the Pacific Decadal Oscillation store energy, release it, get recharged then release it again. El Nino is a classic example of this. Just after an El Nino temperatures go up due to the energy that is released into the atmosphere. Then temperatures go down. Climate oscillations are responsible for much of the year to year natural variability in temperature. Another source is solar insolation. But we know that but for the solar cycle output has been flat to falling since at least 1962 thanks to satellite measurements. Climate oscillations can't create energy. They can only store it then release it. The sun hasn't been producing additional energy. Where is the energy for your natural variability being the "cause most of the 0.6 C of warming over the whole of 20th century" supposed to come from? We know that CO2 absorbs thermal radiation. We are able to easily demonstrate this in a lab. See the "CO2 Experiment" video at the top of this page.) We have known this since the mid 1800s. We are able to measure the absorption spectra of carbon dioxide and other greenhouse gases. We know that in terms of its greenhouse effect carbon dioxide acts primariyly in the region of the spectra centered around 15 μm (15 microns), a wavenumber of 667 cm-1 that is due to the quantized bending mode of the molecule -- which acts in accordance with the principles of quantum mechanics to result in the absorption of radiation in this part of the spectra. We know that absorption keeps going up as you raise the levels of carbon dioxide. Using satellites we are able to image atmospheric carbon dioxide. We are able to see the plumes rising up from the heavily populated East and West coasts of the United States. We can image the carbon dioxide because it reduces the rate at which infrared radiation escapes to space. If energy is escaping the climate system at a reduced rate but entering the climate system at the sate rate as before we know that the amount of energy in the system has to increase. We know that the temperatures have to increase. We know that for every degree Celsius you increase the temperature the humidity of saturation has to increase by 8%. We know that for every 10°C it roughly doubles. And we know that water vapor absorbs radiation, just like carbon dioxide, and are able to satellite image that, too. Water vapor doesn't condense to form clouds unless it exceeds the humidity of saturation -- and the humidity of saturation increases with temperature. By a factor of 2 for every 10°C. RW1 wrote in 47:The bottom line, for me at least, is net positive feedback is an extraordinary claim that requires extraordinary proof, especially since solar energy is not amplified to anywhere near such an extent and since net negative feedback is far, far more logical for a system stable enough to support life as the Earth is.
"... especially since solar energy is not amplified to anywhere near such an extent." It is amplified to roughly the same extent. We can't explain the warm interglacials and ice ages without the amplification due to carbon dioxide (which is released by the oceans when they warm like a warming soda losing its fizz but absorbed when the oceans cool), ice sheets (due to their melting and growth) and water vapor feedback. "... net negative feedback is far, far more logical for a system stable enough to support life as the Earth is." Have you ever heard of the Permian/Triassic Extinction? Nearly all life as we know it was wiped out when a flood basalt supervolcano erupted, sending vast quantities of carbon dioxide into the atmosphere. We won't likely reach that level but something resembling the Paleocene-Eocence Extinction may be within our reach.Moderator Response: [muoncounter] Missing link for 'absorption spectra'. [Daniel Bailey] Tim, I took a shot at what you meant to use for your absorption spectra link. If I was wrong, please let me know what the correct link is & I'll update it. -
johnd at 09:03 AM on 7 March 2011Blaming the Pacific Decadal Oscillation
Tom Curtis at 01:37 AM, re "For a start, during El Ninos, the water surrounding Australia is cooler than normal, yet Australia tends to be hotter than normal." The conditions in Australia are very much subject to what is occurring in the Indian Ocean, perhaps more so, as is evident when trying to find correlation between droughts and the conditions in the oceans surrounding Australia. -
johnd at 08:55 AM on 7 March 2011Blaming the Pacific Decadal Oscillation
RW1 at 08:20 AM, the water vapour having removed heat from the surface, rises to the point where condensation begins, resulting in a nett cooling effect on the atmosphere at that point as the water droplet receives the heat carried by the water molecule. That effect continues on upwards until all moisture in the air has been removed at the highest level where clouds form. The only way to determine the bottom line of the process would be to measure the amount of heat being liberated from the surface by evaporation against the amount of heat that is returned to the surface by rain. -
muoncounter at 08:50 AM on 7 March 2011Blaming the Pacific Decadal Oscillation
RW1, "I don't find them convincing at all" The conclusions in Yeh et al (ref above), are from "calculations based on historical El Nin˜o indices" augmented by "the six climate models with the best representation of the twentieth-century ratio of CP-El Nin˜o to EP-El Nin˜o". Doesn't get much more more convincing than that. "All I'm saying is if natural oscillations can cause ... " Nope, you're ducking that question. What natural forces are these? Are they already accounted for in existing forcing calculations? Are they global? What physical phenomena can be measured to determine their efficacy? It is high time that the 'natural forces' gambit is held to the same level of scrutiny as GHGs. And note that the warming of concern is that rapid rise since circa 1970: 0.15C per decade, not 0.6C in a century.
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muoncounter at 08:33 AM on 7 March 2011A Real-World Example of Carbon Pricing Benefits Outweighing Costs
Gilles: "why are you looking at EIA's predictions ... They can't predict decreasing energy supplies, it's not politically correct." Your source for this analysis is the blog of an independent journalist? Note that EIA's energy from coal curve does indeed decrease for the next 5 years. "do the maths. 15% of the richest part of the world use 50% of the energy" That is exactly the problem. We are the ones who can best afford to explore technology needed to make meaningful reductions. "the net result of improving all the techniques and economy will most probably INCREASE the overall amount of burnt fossil fuels" You seem to be arguing against doing anything because in your opinion, nothing will be an equitable fix. It would help advance the discussion if you provided some real evidence, rather than these sweeping, opinion-based generalizations. -
RW1 at 08:22 AM on 7 March 2011Blaming the Pacific Decadal Oscillation
Moderator, "Moderator Response: Fixed open italics tag." Thank you! -
RW1 at 08:20 AM on 7 March 2011Blaming the Pacific Decadal Oscillation
RickG, Yes water vapor is tied to temperature - meaning higher temperatures are associated with increased water vapor/evaporation. But the whole cycle of surface water -> water vapor -> clouds -> precipitation -> surface water is what's driving the whole water based feedback mechanism and the energy balance - not just the water vapor alone. That was my point. "As for clouds, those with small water droplets (lighter clouds) tend to reflect light while those with larger water droplets (darker clouds) tend to absorb more light. Am I wrong?" I'm not sure. -
Riduna at 08:12 AM on 7 March 2011A Real-World Example of Carbon Pricing Benefits Outweighing Costs
Marcus has noted that a common argument advanced by those opposed to pricing carbon by way of a carbon tax/levy or cap and trade system is that in doing so we deprive ourselves of the cheapest, most efficient and transportable energy sources known to man. Inevitably, this must result in damage to the economy. Others have pointed out that the price we pay for energy is relatively cheap compared with energy produced from renewable sources because of our failure to develop technology needed to produce competitively priced energy from renewables and because of the subsidies paid to the producers – and sometimes the users – of fossil fuels. Some have reminded us that oil is a finite commodity and that having reached peak oil, probably in 2008, making the future for oil-based fuels is one of decreasing availability and increasing price. Eventually, probably over the next 30 years, the point will be reached when it becomes unaffordable even for mass transport. But there is quite a different price on the use of fossil fuels which will be and already is being exacted on every man, women and child on this planet. That is the price we are all going to pay in terms of the effects of increasing CO2 emissions, the most notable of which are: • On-going and accelerating rise in global surface temperatures • continued, faster melting of the polar ice caps and sea-ice • dangerous sea level rise and coastal flooding • melting of land based snow and ice, contributing to • shortage of water in densely populated areas • loss of capacity to produce food for rapidly growing populations • extinction of flora and fauna dependent on cooler climates • increased risk of fire and flood destroying valuable assets • spread of potentially fatal diseases into areas now free of them • ocean acidification endangering marine life forms • increased incidence and severity of climate events • increased water vapor in the stratosphere causing further warming • melting clathrates releasing methane, making global warming faster. To varying degrees these effects have already become evident but they do not pose an obvious danger – yet. This is because their development is prolonged and slow but it is inexorable. We either price carbon now and curb our CO2 emissions or we shall pay a much, much higher price – one which can threaten our survival as a species on this planet. -
RickG at 08:07 AM on 7 March 2011Blaming the Pacific Decadal Oscillation
RW1: But water vapor is tied directly to clouds and precipitation, which ultimately remove the water vapor from the air and return it to the surface. Forming clouds from the water vapor reflect incoming sunlight and precipitation is typically cooler than the surface, so both counter act negative feedbacks to water vapor. Really! I thought water vapor was tied to temperature. As for clouds, those with small water droplets (lighter clouds) tend to reflect light while those with larger water droplets (darker clouds) tend to absorb more light. Am I wrong? -
dana1981 at 07:58 AM on 7 March 2011A Real-World Example of Carbon Pricing Benefits Outweighing Costs
For the record, I own an electric motorcycle, and it's freaking awesome. daisym #68 -"we must find a new energy source to replace carbon fuels. Period. So, why aren't we looking?"
We are looking. There's solar (PV and concentrated thermal), wind (offshore and onshore), geothermal, tidal, etc. etc."Making "investments" in energy saving things has little economic benefit, except for the early investors"
That's not true. Californians use less per capita energy than most of the rest of the USA, but our rates aren't significantly higher than the average."Because government isn't looking for this replacement energy source, I wonder if carbon fuels are really the threat to humanity we've been told."
Two major problems with this question: 1) It's based on a false premise. As noted above, we most certainly are looking for replacements. And as noted in the article, the RGGI states spent 11% of their carbon funds on renewable energy. 2) The scientific evidence is what it is, and it clearly shows that carbon is a threat to humanity. Whether governments choose to act on it or ignore it does not change the science. The fact that we have rather shortsighted politicians in charge who either don't understand the threat or are unwilling to act on it doesn't change the existence or magnitude of threat. -
RW1 at 07:50 AM on 7 March 2011Blaming the Pacific Decadal Oscillation
dhogaza (RE: 48), "Warmer air will hold more water vapor, regardless of the sources of warmth, and this is a large positive feedback that is not an "extraordinary claim", as it's been known for ages." I don't dispute that the water vapor feedback, by itself, is positive. But water vapor is tied directly to clouds and precipitation, which ultimately remove the water vapor from the air and return it to the surface. Forming clouds from the water vapor reflect incoming sunlight and precipitation is typically cooler than the surface, so both counter act negative feedbacks to water vapor. "The extraordinary claim is that negative feedbacks will be large enough to offset this and other (relatively minor) positive feedbacks." Virtually every natural system, micro or macro, is dominated by net negative feedback, especially those stable enough to support life. The human body is good example. When the internal body temperature starts to cool down, internal feedback mechanism kick in that warm it up and vice versa - keeping a relatively constant internal temperature. Net postive feedback is the extraordinary claim. "As it turns out, reality, including that described by physics and other sciences, is often "illogical" and unintuitive." Sometimes, yes, but highly doubtful in this case, especially given that varying incoming solar power is clearly opposed by the system rather than re-enforced and the response of the system to solar power is so much less.Moderator Response: Fixed open italics tag. -
dhogaza at 07:27 AM on 7 March 2011Blaming the Pacific Decadal Oscillation
The bottom line, for me at least, is net positive feedback is an extraordinary claim that requires extraordinary proof, especially since solar energy is not amplified to anywhere near such an extent
Warmer air will hold more water vapor, regardless of the sources of warmth, and this is a large positive feedback that is not an "extraordinary claim", as it's been known for ages. The extraordinary claim is that negative feedbacks will be large enough to offset this and other (relatively minor) positive feedbacks.net negative feedback is far, far more logical for a system stable enough to support life as the Earth is.
As it turns out, reality, including that described by physics and other sciences, is often "illogical" and unintuitive. -
daisym at 07:20 AM on 7 March 2011A Real-World Example of Carbon Pricing Benefits Outweighing Costs
I think everyone is missing the point. The point is, we must find a new energy source to replace carbon fuels. Period. So, why aren't we looking? What good are all of the carbon tax schemes in the world, if we don't spend the tax money on R&D for a full time replacement energy source? Making "investments" in energy saving things has little economic benefit, except for the early investors. Over a short period of time, energy costs must rise. The electric company requires a "fixed" revenue stream to maintain the grid, regardless of reductions in consumption. If its customers use less electricity, then this fixed cost forces an offsetting rate increase levied on the reduced consumption. Similarly, the U.S. Post Office continues to raise postal rates to replace revenues lost to electronic mail. Until email was invented, we had to rely on the Postal Service to carry the mail. Until a 24/7 alternative to carbon fuels is invented, we will continue to rely on carbon fuels. Because government isn't looking for this replacement energy source, I wonder if carbon fuels are really the threat to humanity we've been told. -
Marcus at 06:58 AM on 7 March 2011A Real-World Example of Carbon Pricing Benefits Outweighing Costs
Gilles, I don't need an electric car, as I use buses & trains to get everywhere-so my own transportation based CO2 footprint is already extremely low. -
RW1 at 06:56 AM on 7 March 2011Blaming the Pacific Decadal Oscillation
muoncounter (RE: 40), "Now you are making a major assumption with the contention that all of ENSO is an entirely natural oscillation. From Yeh et al 2009:" The conclusions in that paper are highly presumptuous given that relatively little is known about what actually causes ENSO to occur. I don't find them convincing at all. "Here you're assuming that such slow oscillations exist at all, let alone in sufficient amplitude to 'cause' any such change. Then you'd have to explain why 'slow' oscillations cause rapid temperature increase in a pattern that accelerates (increases in rate of change) towards the Arctic." Not really. All I'm saying is if natural oscillations (variations) can cause up to 0.5 C of temperature change in one year, why couldn't natural forces cause most of the 0.6 C of warming over the whole of 20th century? "It would be interesting indeed if you applied the same zeal that you've shown for testing forcing theory to Spencer's calculations referenced in the context of Figure 3 of this post. That would be the skeptical thing to do. I haven't yet read Spencer's post, but I will take a look at it and possibly comment. The bottom line, for me at least, is net positive feedback is an extraordinary claim that requires extraordinary proof, especially since solar energy is not amplified to anywhere near such an extent and since net negative feedback is far, far more logical for a system stable enough to support life as the Earth is. -
Gilles at 06:40 AM on 7 March 2011A Real-World Example of Carbon Pricing Benefits Outweighing Costs
Marcus, how is your own electric car working? Muoncounter : why are you looking at EIA's predictions that have repeatedly proven to be wrong in the last years? http://petrole.blog.lemonde.fr/files/2010/11/eiaieooilprojections2000-2010.1290092704.png the falling curves that suddenly increase again in the next years are simply not reliable. Official agencies have persistently underestimated the peaking of production of many countries : US, north sea, mexico. They can't predict decreasing energy supplies, it's not politically correct. others: I am not saying that energy conservation is impossible, nor of course that it shouldn't be done. I say first that it is probably of limited value since the fossil fuel production will eventually vanish, and the productivity won't go to infinity. So energy conservation can mitigate partly the decline of energy, but not completely offset it. Second, even if you reduce the consumption of energy in OECD, how can you justify to prevent the poorest people to use it? do the maths. 15 % of the richest part of the world use 50 % of the energy, so a ratio 6 to 1 compared to the poorest. Even if they halved their energy consumption (going to 3 to 1) this would only correspond to an increase of 50 % for the poorest. How can you prevent them to raise to 1,5 , still one half of the richest? so you can't prevent poor people to use the energy you're sparing (I am not saying this shouldn't be done : it's a fair thing to make our world more equitable. I'm just saying this will not reduce the overall consumption. And it won't either reduce the total amount of fossil fuels that we can extract : usually, a more efficient economy is still more efficient to get scarer resources - so the net result of improving all the techniques and economy will most probably INCREASE the overall amount of burnt fossil fuels... -
Albatross at 06:33 AM on 7 March 2011The Climate Show Episode 8: Kevin Trenberth
I am very much looking forward to listening to this episode. -
dana1981 at 05:22 AM on 7 March 2011A Real-World Example of Carbon Pricing Benefits Outweighing Costs
actually thoughtfull #62 - I think your numbers are off a bit there. As I recall, over 90% of daily driving in the USA is under 40 miles. Gilles #53 - you're missing the fact that with a carbon price, it creates a revenue stream which can be used to fund energy efficiency programs, as we saw in the RGGI case. When these programs are made more readily available to the public, people will be more likely to take advantage of them. For example, my local electrical utility has a program to make low income homes more energy efficient at no cost. Several years ago when I qualified, I took advantage of the program, and now my home is much more energy efficient. -
Timothy Chase at 05:08 AM on 7 March 2011Blaming the Pacific Decadal Oscillation
It might help if we know what the notation means, eh? From the essay:The greenhouse effect can be defined as ([equations] 8-10)
Ga = σ(SST)4 - F+ ([equation] 1)
According to the Stefan Boltzmann law, σ(SST)4 is the infrared black body emission by the surface at temperature SST, σ=5.67 X 10-8 Wm-2 K-4 is the Stefan Boltzmann constant, and F+ is the outgoing infrared radiation flux at the top of the atmosphere. -
Blessthefall at 04:57 AM on 7 March 2011A Real-World Example of Carbon Pricing Benefits Outweighing Costs
@Rob: Regarding the graph of food prices you provided - http://www.globaldashboard.org/2011/03/03/did-we-say-feed-the-future-oh-we-meant-feed-car-engines/ -
Gordon1368 at 04:44 AM on 7 March 2011The Climate Show Episode 8: Kevin Trenberth
I watched the entire show, it is very good, and it was a pleasure to see and hear some of the people I have been reading about lately. John Cook's explanation of the misuse of the term "hide the decline" was concise and clear, and I wonder if stevee (Post #1, possibly already deleted) even bothered to watch it before posting his reaction to seeing the name "Trenberth" in the tile. My thanks to the people who provide this site, and also to the many contributors who take on the thankless task of responding to the endless stream of willful deniers. I understand questioning the science, in order to deepen understanding, but I am tired of the stream of people who treat it like a rhetorical game, in which debating points can be scored by clever misinterpretation and a degree of facility with scientific terminology. -
Blessthefall at 03:51 AM on 7 March 2011A Real-World Example of Carbon Pricing Benefits Outweighing Costs
@Rob: Regarding the food prices, I think you're suggesting that weather extremes cause food prices to go up... whether it be a heat wave in Russia or the recent cold snap in Mexico. Gotta run now, but i'll respond to your other points later. -
Timothy Chase at 03:30 AM on 7 March 2011Blaming the Pacific Decadal Oscillation
Tom Curtis wrote in 42:A very good point, that I did not think of. (That's the advantage of not being an expert - I get to make silly mistakes every now and then.)
I make a fair number of mistakes, too. You have to be willing to make mistakes if you wish to learn since almost inevitably part of the process. And I am not an expert, either. Just a philosophy major turned computer programmer -- who will often preface what he is about to say with, "As I understand it..." Tom Curtis wrote in 42:However, I am still not happy with the story that the increase in mean global temperatures is just due to atmospheric heat transport from the warm El Nino waters. For a start, during El Ninos, the water surrounding Australia is cooler than normal, yet Australia tends to be hotter than normal. That is probably due to reduced cloud cover, but that means feedback effects can still be a significant factor.
There are feedbacks, but they are part of the El Nino itself, not something that happens afterwards as some sort of lagged feedback that causes global temperatures to rise after the El Nino. One of the more interesting feedbacks is referred to as a clear sky "super greenhouse effect" that occurs over tropical ocean where downwelling radiation increases more rapidly than upwelling radiation -- which is a result of increased water vapor. Please see: Valero, F. P. J., W. D. Collins, P. Pilewskie, A. Bucholtz and P. J. Flatau (1997) Direct Radiometric Observations of the Water Vapor Greenhouse Effect Over the Equatorial Pacific Ocean, Science, 275, 1773–1776. From the abstract:Airborne radiometric measurements were used to determine tropospheric profiles of the clear sky greenhouse effect. At sea surface temperatures (SSTs) larger than 300 Kelvin, the clear sky water vapor greenhouse effect was found to increase with SST at a rate of 13 to 15 watts per square meter per Kelvin. Satellite measurements of infrared radiances and SSTs indicate that almost 52 percent of the tropical oceans between 20°N and 20°S are affected during all seasons. Current general circulation models suggest that the increase in the clear sky water vapor greenhouse effect with SST may have climatic effects on a planetary scale.
... and from the paper itself:Satellite studies (8–10) have found that for clear skies and SSTs above 298 °K, the spatial variation of Ga with SST, dGa/d(SST), exceeds the rate of increase of sea surface emission, ds(SST)4/d(SST) = 4σ(SST)3. For a tropical SST of 300 °K, 4σ(SST)3 ~ 6.1 W m-2K-1. This effect, termed the "super greenhouse effect" (11), occurs in both hemispheres during all seasons. It is also observed for interannual variations of Ga with SST during the El Nino in the tropical Pacific (12). Observations in the tropical Atlantic ocean (11) show that the clear sky downwelling infrared flux incident on the surface (Fa-) also increases faster than the surface emission with increasing SST. The net result is further warming of the surface, which in turn induces additional heating of the atmosphere column above.
However, what you are describing is a bit different -- and in terms of the effects at least the inverse of what we see up in the Seattle area. In Seattle we have warmer waters just off the coast, but this is only over a thin strip of water. Cool air blows in off of the cooler than normal North Pacific Ocean. In the case of Australia, however, I believe what is happening is the result of a decrease in moist air convection. With less precipitation there is less evaporation and the moist air convection by which the surface normally loses much of its excess heat. The same thing is supposed to dry out the continental interiors in the decades to come. Land warms more quickly than ocean due to the differences in thermal inertia. Warmer ocean temperatures will imply a higher absolute humidity over the ocean surface and over land, but as temperatures are higher in the continental interiors the humidity of saturation will be still higher inland and during the summers the relative humidity will drop more as you move inland. Therefore there will be less precipitation and reduced moist air convection carrying heat away from the surface. Thus during the summer months, when you need the cooling effects of moist air convection the most, it will be reduced, causing temperatures to rise still further. -
Tom Curtis at 03:05 AM on 7 March 2011The Good, The Bad and The Ugly Effects of Climate Change
Berényi Péter @84, this study shows that the ideal temperature (for the Dutch) is 16.5 degrees C, with mortality increasing 1.75 times as fast for each degree over as it does for each degree under (on average) but still showed more deaths from cold than from heat. Presumably this is because in Holland, the coldest days are much further below the safe level than the hottest days are above it, although different heat responses to different diseases may also be relevant. Similar studies in England and the US show varied effects. In England the cold related mortality is higher, whereas in the US, with a mixture of temperate and subtropical cities, it was found that there are no cold related deaths in subtropical cities, although there are heat related deaths. There are both heat and cold related deaths in temperate cities. The obvious conclusion is, firstly, that you estimate that 26.74 degrees C is the temperature that minimizes temperature related effects on mortality is in significant error. Even if it were not, such temperatures are typical of mean summer temperatures in the tropics. Further, for the majority of the world's population (who live in the tropics and subtropics) heat is a potential killer, but cold is not. Your equation that we should go for higher temperatures to reduce mortality only makes sense if the deaths of people of the tropics and subtropics is inconsequential compared to those of people in temperate zones. Even in temperate Holland, Business As Usual scenarios will raise temperatures sufficiently as to turn around the proportion of those killed, so that heat becomes the major killer rather than cold. Arguably, the reduction in cold related deaths will compensate for the increase in heat related deaths. But in that case the equation for increased temperatures is no significant change in temperature related deaths in temperate zones; but a significant increase of them in the tropics and sub tropics.We conducted the study described in this paper to investigate the impact of ambient temperature on mortality in the Netherlands during 1979–1997, the impact of heat waves and cold spells on mortality in particular, and the possibility of any heat wave- or cold spell-induced forward displacement of mortality. We found a V-like relationship between mortality and temperature, with an optimum temperature value (e.g., average temperature with lowest mortality rate) of 16.5°C for total mortality, cardiovascular mortality, respiratory mortality, and mortality among those ≥ 65 year of age. For mortality due to malignant neoplasms and mortality in the youngest age group, the optimum temperatures were 15.5°C and 14.5°C, respectively. For temperatures above the optimum, mortality increased by 0.47, 1.86, 12.82, and 2.72% for malignant neoplasms, cardiovascular disease, respiratory diseases, and total mortality, respectively, for each degree Celsius increase above the optimum in the preceding month. For temperatures below the optimum, mortality increased 0.22, 1.69, 5.15, and 1.37%, respectively, for each degree Celsius decrease below the optimum in the preceding month. Mortality increased significantly during all of the heat waves studied, and the elderly were most effected by extreme heat. The heat waves led to increases in mortality due to all of the selected causes, especially respiratory mortality. Average total excess mortality during the heat waves studied was 12.1%, or 39.8 deaths/day. The average excess mortality during the cold spells was 12.8% or 46.6 deaths/day, which was mostly attributable to the increase in cardiovascular mortality and mortality among the elderly. The results concerning the forward displacement of deaths due to heat waves were not conclusive. We found no cold-induced forward displacement of deaths. Key words: cold spells, heat waves, mortality, mortality displacement, Netherlands, temperature. Environ Health Perspect 109:463–470 (2001). [Online 3 May 2001]
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andthorne at 02:58 AM on 7 March 2011Blaming the Pacific Decadal Oscillation
Below is an edited email that I sent to NOAA almost four years ago telling them that I thought that El Nino and La Nina were caused by the actions of methane hydrates. At the time I did not know that the name for the conversion of the organic bedrock "shale" via liquid CO 2 was called the "retorting of shale oil" and I got some other things- not so much wrong as incomplete. I had only been reading about the topic for about six months;but the basic theory that I put forth that El Nino and La Nina are probably cause by the heat trapping cabilbities of the hydrates must be looked into. The year 2007 is also the year i first started to contact bee researchers and the USDA to tell them our problem with the bees was formaldehyde gas in excess in our atmosphere due to rising levels of ethane which oxidzes to the deadly gases of formaldehyde and carbon monoxide before proceeding to CO2. Shortley thereafter the light bulb went on that our excess CO2 was from methane oxidation, not our cars and factories. Andrea Silverthorne ----- Original Message ----- From: "Newstar Realty" -
muoncounter at 02:56 AM on 7 March 2011The Good, The Bad and The Ugly Effects of Climate Change
BP: "monthly mortality data for the UK from the Office for National Statistics for the period January 2006 - January 2011." Interesting choice of both time period and locale. The UK was at the edge of the 2010 heatwave:
The same could be said for 2007:
At least those events were within your time sample. Perhaps going back to the 2003 heatwave would be appropriate; although reported mortality in France and Germany was 10x that of the UK.
"if human lives are to be saved, we should clearly go for higher temperatures. "
Health professionals take this question seriously, so we do not have to rely on ad hoc analysis. From Ippoliti et al 2010:
The effect of heat waves showed great geographical heterogeneity among cities. Considering all years, except 2003, the increase in mortality during heat wave days ranged from +7.6% in Munich to +33.6% in Milan. The increase was up to 3-times greater during episodes of long duration and high intensity. ... The highest effect was observed for respiratory diseases and among women aged 75-84 years.
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RW1 at 02:55 AM on 7 March 2011Blaming the Pacific Decadal Oscillation
Tom (RE: 36), "If it was not a feedback mechanism, the global temperature effects would exactly coincide with the temperature effects on the surface of the pacific ocean, and would equal the surface temperature effects on the tropical pacific divided by the area effected. As it happens, the maximum global temperature effect lags the maximum surface temperature effect in the Pacific, and is larger than the proportional change in SST. Because the global temperature response lags ENSO, the causal direction must be ENSO -> global temperature response, rather than the other way round. Hence, it is a feedback." What you are describing here is a Time Constant (a lag between an initial change and final effect) - not a feedback. Feedback is a separate mechanism that opposes or amplifies the change. "No assumptions. The increase of globally averaged specific humidity with El Ninos (and decrease with La Ninas) is a well known phenomenon. The 1998 spike in humidity is as obvious as the spike in temperature. Further, the connection between high humidity and high temperatures is also well established by theory and observation. El Ninos and La Ninas are caused by variations in the strength of the Walker circulation, which are in turn driven by changes in the relative temperature between the Eastern and Western tropical pacific. So, the Walker circulation in effect acts as a feedback mechanism to that variation. What causes the initial variations is more dubious, with a number of factors implicated (and it is unlikely to be a single factor)." Well, what causes the initial variations is the key, isn't? Is it an internal or external forcing? Again though, you're mistaking a Time Constant for a feedback mechanism. "Again, I know that it is a positive feedback because of the relative magnitude of the response. The maximum area affected by an El Nino is approximately one ninth of the Earth's surface. This excludes those parts of the Pacific that are cooled in an El Nino, which if included would weaken the calculated initial response (and hence strengthen the calculated feedback). The minimum area warmed is about 1/27th of the Earth's surface. It is difficult to estimate the total area warmed, but with very high confidence it lies between these two extremes. So, 2 degrees over one ninth of the Earth's surface, globally averaged is 0.22 degrees, much less than the 0.5 degree global increase. Hence the feedback must be positive. And that is the very conservative estimate, as it allows the maximum possible warming extent, and does not consider the cooling at other regions." But what percentage of the Earth's thermal mass is warmed? That's a more difficult question, but one that would need to be answered, especially since only 2/3rds of the planet is ocean and the ocean is most of the thermal mass. Also, the phenomenon doesn't seem well understood enough to know that the area you cite in the Pacific is solely responsible for the full globally averaged warming effect. "Again the caveat, this is beer coaster mathematics, and only indicates ball parks. It is certainly accurate enough to show the sign of the feedback, but not accurate enough to narrow the magnitude significantly. None-the-less, the correlation does hold that the stronger the effect of ENSO on global temperatures, the stronger the positive feedback involved, and hence the stronger the positive feedback from CO2 induced warming. @ 34: Perhaps it will make it easier when you remember that a positive feedback enhances both warming from an initial warming, and cooling from an initial cooling. The return of Pacific SSTs to normal values after an El Nino is a cooling, of equal magnituded to the initial warming. It will therefore generate a cooling feedback of equal magnitude to the initial warming feedback, thus cancelling it out." This doesn't make sense to me. A forcing that causes a warming and then ceases or fully subsides is not an equal and opposite cooling effect - it's a simply a cessation of the forcing that caused the warming. In order to get an equal and opposite effect, you would need a forcing that causes cooling below the initial state prior to the warming forcing. Positive feedback is defined as feedback that amplifies or reinforces change. If the feedback is net positive, in the case of warming, then the feedback causes more warming above and beyond the initial intrinsic warming. If or when the intrinsic warming stops, the amount of warming above and beyond from the feedback remains. Why doesn't the net positive feedback continue to amplify the remaining warming? Clearly this doesn't happen. -
actually thoughtful at 02:48 AM on 7 March 2011A Real-World Example of Carbon Pricing Benefits Outweighing Costs
To further the advantage of electric cars- 8 normal sized solar panels (3 foot by 5 foot - ~1.7 square meters) will charge that electric car for its 100 mile range (Nissan Leaf). 100 miles covers over 60% of Americans average daily driving. You may need a 2nd car - gas guzzler - for long trips. I run a plumbing business with a service area of 250 square miles - I RARELY exceed 100 miles in a given day. And if I do - I know I am going to so I can either take a different vehicle, or I can borrow some electrons along the way. -
muoncounter at 02:20 AM on 7 March 2011Icing the Medieval Warm Period
RickG, "aerosols being very short-lived in the atmosphere certainly would not be as prevalent in the southern latitudes " Good point. In addition, those graphs illustrate that claims of 'flattening and 'no sign of significant acceleration since 1970' are utterly devoid of contact with observations. -
Berényi Péter at 02:07 AM on 7 March 2011The Good, The Bad and The Ugly Effects of Climate Change
"Warmer winters would mean fewer deaths, particularly among vulnerable groups like the aged. However, the same groups are also vulnerable to additional heat, and deaths attributable to heatwaves are expected to be approximately five times as great as winter deaths prevented." The proposition in bold above may actually be true. It depends on who is supposed to expect such a thing. If it refers to those who don't bother having a look at actual data, it's fine. However, a slightly modified version of this proposition like "[number of] deaths caused by heatwaves will be approximately five times as great as winter deaths prevented" is certainly false. It just emphasizes the importance of avoiding language of marketing when talking about science. We can get monthly mortality data for the UK from the Office for National Statistics for the period January 2006 - January 2011. We can also get monthly temperature data from the Met Office for the same epoch for stations scattered evenly above the UK. From these it is easy to calculate a scatter plot of average daily mortality rate as a function of monthly mean temperature and we can do a least square fit of a quadratic function on it.
It turns out this quadratic has a minimum at 26.74°C, that is, as annual average temperature of the UK is currently under 10°C, any conceivable warming would decrease mortality there, even in summertime (warmest month in this period was July 2006 with 18.4°C).
What is more, there are very few places on the entire globe where monthly mean temperature exceeds 26.74°C for any month of the year.
Therefore if human lives are to be saved, we should clearly go for higher temperatures. That's not to say a heat wave can't kill, but as global average temperature is below 15°C, in a warming world number of lives saved from death by cold would always exceed the number killed by heat as long as we don't have more than 10°C increase in global average temperature. And no one is projecting that much under any reasonable scenario.
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