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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.

Recent Comments

Comments 20401 to 20450:

John Mason at 14:59 PM on 10 April 2017

Past and Future CO2

The Foster et al paper is now available at:

http://www.nature.com/articles/ncomms14845

Glenn Tamblyn at 14:22 PM on 10 April 2017

Science of Climate Change online class starting next week on Coursera

curiousd

The person to contact regarding this would be Professor David Archer at UoC. The Modtran calculator site is part of a set of tools he uses in running on-line courses about climate science.

d-archer@uchicago.edu

Paul D at 05:51 AM on 10 April 2017

The Myth of 'Clean Coal'

Should have said in my comment at (3) that the Southampton CHP plant uses gas not coal. It provides heat to local domestic customers and refrigeration and heat to a large retail complex, the electricity is sold to the docks.

Paul D at 05:37 AM on 10 April 2017

The Myth of 'Clean Coal'

Ironically some of the best research into the inefficiencies of producing energy from coal has been produced by US government researchers.

They spotted the obvious in that no powerplant can extract all the energy from a piece of coal and that is even before taking into account the losses created from the energy that can be extracted.

Humanity has wasted a lot of potential that was ever in coal even before you take into account it's horrendous polluting qualities.

One obvious flaw is the poor thermal energy efficiency of power stations. Most power stations would be better off as CHP plants with the main product being heat and refigeration from the 60% wasted energy. That leaves 40% for electricity production - a secondary product (or it should be).

That of course requires a near socialist attitude towards energy production as the heat and cooling products MUST be used by local residents and businesses without much competition!

This is done at one location in the UK (Southampton) and many Scandanavian locations.

bjchip at 05:35 AM on 10 April 2017

Inconceivable! The latest theatrical House 'Science' committee hearing

Adding to that excellent link ( 10: John Hartz ) would be this

http://www.vox.com/science-and-health/2017/1/27/14395978/donald-trump-lamar-smith

The T-rump taking an obvious place in the Lysenko comparison, and more obvious now than ever.

Mike Blair at 04:19 AM on 10 April 2017

Sea ice falls to record lows in both the Arctic and Antarctic

The article title "Sea ice falls to record lows in both the Arctic and Antarctic" has been misinterpreted by some deniers in UK. They probably have not read the article, but they take 'record' to be a verb, not an adjective, and so are claiming that the sea ice levels haven't fallen as low as predicted. I suppose it's the law of unintended consequences, and the article itself couldn't be plainer in its explanation, but please, take a little more care!

curiousd at 23:47 PM on 9 April 2017

Science of Climate Change online class starting next week on Coursera

I thank M.A. Rodger for his critique; it is exactly what I want.

(1) I can think of no other way to "disseminate the corrections to the Modtran online community directly " than to post such corrections as I have developed on "Skeptical Science" and "Science of Doom".

(2) The corrections I have made use SpectralCalc, a relatively inexpensive and wonderful tool for learning or teaching about atmospheric science. It would go well with Modtran. I can go further and take my violation of the plane - parallel approximation into account.

(3) I am not sure what you mean about the 1.7 factor being the correction I make. The1.7 factor is to expand the underlying wavelength range in the most correct way; to make the most "correct correction" . I cannot (or have not yet taught myself how to do it) actually integrate the intensity over many different angles. Modtran Chicago does this; that is better than my method, which is to use the "diffisivity approximation" approach and multiply by pi whilst at the same time effectively switching from a vertical path to one at 54 degrees. My table in post nine shows that by using a vertical path corresponding to 693 ppm - which has the identical effect as a straight line path at 54 degrees and 400 ppm - I can nearly duplicate the Modtran result for "CO2 only" where the Modtran result is for 400 ppm but they integrate outgoing intensity over all directions. I then carry over the 1.7 so that my "correction is more correct" for the water vapor bands. My correction is to expand the band width to 2 wn through 2200 wn from the original 100 wn to 1500 wn.

With respect to the comparison to Chen, et al: Since I use the U.S. Standard Atmosphere, which is supposed to be a type of world wide average, why is it so unexpected that my result isclose to that of Chen, et al ?

(You get something pretty close to the correct CO2 only climate sensitivity if you use MILA in U.S. standard atmosphere and the 0.98 emissivity; despite the fact that the present best value is by Myhre, who I believe found it improved the result to average over many locations? M.A. Rodgers, is the previous italacized sentence correct ?)

Also, regarding your criticism: Thus your 260.2w/sqm is calculated from MODTRAN applies only to "1976 U.S. Standard Atmosphere" and "No Cloud or Rain".

The idea of a "Clear Sky" OLR measurement is to obtain the OLR with no clouds or rain. Otherwise it would not be a clear sky experiment.

MA Rodger at 19:54 PM on 9 April 2017

Science of Climate Change online class starting next week on Coursera

curiousd @6-10,

The first question to ask you is - Have your "corrections" been "disseminated directly within the Modtran user community online" ? As you report @6, it is the advice of the BAMS editors that you should do this. It would also be my advice.

The two "corrections" you describe here (if I understand correctly) concern firstly the impact of IR beyond the range 6.67-100μm which you calculate as being significant yet outside the calculations made by the MODTRAN model, and secondly the lack of spherical adjustment for height in that model.

Regarding the first of these, using the on-line calculator at SpectralCalc.com, the value of blackbody radiation beyond 6.67-100μm amounts to 3.6% at 255K. I would assume the creators of MODTRAN were not unaware of that situation when they determined the wavelength limit of the model.

Regarding the second correction, the spherical effect on IR flux over 70km of atmosphere would be about 2%. While this may or may not be of significance to the MODTRAN model, the adjustment you make to the MODTRAN inputs to simulate this effect is surely incorrect. Your adjustment is "multiplying the standard ropospheric water vopor concentration" by 1.7. Concerning your use of Chen et al (2013) to provide a check on your correction, you should note that the value in Chen el al Table 3 is a "near-earth global annual mean" and so not actually comparable with any setting available on the MODTRAN interface. Those settings only provides for certain 'Locality' and weather, settings which greatly impacts the "Upward IR heat flux" . Thus your 260.2w/sqm is calculated from MODTRAN applies only to "1976 U.S. Standard Atmosphere" and "No Cloud or Rain".

curiousd at 19:00 PM on 9 April 2017

Science of Climate Change online class starting next week on Coursera

Glenn, I don't think I am criticizing the Modtran site at all. It is an excellent teaching tool and my point is that an instructor could use these corrections along with Modtran to better illustrate certain important results. For instance, I suspect most students would never look at the underlying program button, and therefore simply stating someplace on the web site or in classroom hand outs that an emissivity of 0.98 is assumed and there is a cut off issue would improve things.

As a case in point, I myself went down the following dead end regarding the emissivity issue. If one simply takes the MILA OLR looking down from the surface and compares to what is expected from the Stefan Boltzmann law you appear to have an emissivity of 0.92 because of the cut offs at 100 wn and 1500 wn. But at time I was using MILA for my purpose I had no clue about the cut offs and assmed the program must assume an emissivity of 0.92.

If someone is using the MILA program to test whether he/she is correctly using Scwarzchild's equation to obtain, say, the co2 no feedback climate sensitivity---where else can you obtain the OLR versus altitude, even in any textbook?---that person will run into contradictions with such a low assumed emissivity. (This is the subject of my next post here.)

All this would be improved just by warning the user of the wavelength cutoffs and that the assumed emissivity is 0.98 not 0.92 on the output website the user uses. The way I discovered this, after months of work, was to digitize the output of MILA and integrate the case of co2 only at 400 ppm and then test my use of the trapezoid rule for integration. I happened to have used an underlying Planck distibution that went from 5wn to 2000 wn. My answer for the integration was significantly too large. So I changed the range of the integration to 100 wn to 1500 wn and got close to the MILA output.

Then I knew.

Glenn Tamblyn at 18:11 PM on 9 April 2017

Science of Climate Change online class starting next week on Coursera

curiousd

Here is a link, from the UoC site, to a technical summary of MODTran from the company who wrote the code - Spectral Sciences Inc. Note the distribution list to the Air Force. Note on the first page of the introduction, the range of wavenumbers is from 0 to 17,900 cm^-1. This upper limit is defined by the range of the data in the HiTran database, not a limit in the code per se.

http://climatemodels.uchicago.edu/modtran/berk.1987.modtran_desc.pdf

Glenn Tamblyn at 18:00 PM on 9 April 2017

Science of Climate Change online class starting next week on Coursera

curiousd

Just a point of clarification. MODTran is a commercially available medium resolution Radiative Transfer Code. It is developed by the US military, primarily through the Air Faorce laboratory system, although they outsource the actual coding. In contrast the Uni of Chicago is hosting a copy of MODTran and supplying configuration parameters to it for their web interface and then showing results from their run.

So the criticisms you are making are more likely related to the configuration setup by UoC not anything built into the software itself which is a more general purpose tool. The emissivity of 0.98 for example would be their setup parameter, and is actually a reasonable average of the actual emissivities of materials on the Earths surface which tend to range between 0.96 to 0.995. Similarly the wavenumber range will be a choice by UoC, rather than built in.

curiousd at 11:31 AM on 9 April 2017

Science of Climate Change online class starting next week on Coursera

Correction number two

Clear sky OLR measurements from satellites are of considerable interest since the properties of the atmosphere are being studied without the complications of cloud cover. For the "Modtran Infrared Light in the Atmosphere" (MILA) leave all default settings of greenhouse gases in place but choose the U.S. Standard atmosphere with no clouds. The uncorrected clear sky output flux observed by the virtual observer at 70 km is 260.2 W/m².

It should be kept in mind in what follows that unlike CO2, which maintains a constant concentration up to ~ 100 km, the water vapor content is concentrated close to the Earth's surface. (This may be seen by clicking the "temperature" button underneath the plot of altitude versus temperature in MILF, and compare CO2 andwater vapor on the drop down menu.)

Using the same SpectralCalc atmospheric path radiance application described in the previous two posts, I set the water vapor scale of the water vapor path to 1.7 instead of the default 1.0. This corresponds to the diffusivity approximation with an effctive angle to verticalof 54 degrees as described in the previous two posts. The radiant emission is calculated for the bands between 2 wn to 100 wn and 1500 wn to 2200 wn, again as described above. These outputs are associated with water vapor since the atmosphere for these wavelength ranges is essentially transparent to CO₂ but the water vapor is a strong absorber. For a .98 emissivity, the corrected OLR is 266.7 W/m² . If the Modtran output is - in addition to adding the pieces between 2 and 100; 1500 to 2200 wn, adjusted to correspond to an emissivity of one for the Earth's surface, the clear sky OLR becomes 272.1 W/m² . This is compared to the value of the clear sky OLR obtained by Chen, Huang, Loeb, and Wei using the AIRS spectrometer of 273.74 W/m²

Chen, et al "Comparisons of Clear - Sky Outgoing Far IR Flux Inferred from Satellite Observations....." Table Three, Journal of Clima,Vol 30, No 9, May 2017.

curiousd at 10:13 AM on 9 April 2017

Science of Climate Change online class starting next week on Coursera

Altitude in km, OLR in W / M²

Altitude S.Calc 683 ppm Modtran 400 ppm

0 360.2 360.2

1 357.5 357.6

2 353.1 352.9

3 348.5 348.5

4 344.5 344.4

5 340.2 341.0

6 336.4 337.5

7 333.1 334.4

------------------— skipping several entries

18 320.8 324.6

Only major isotopologue of CO2 used in Spec Calc results. Again, 0.98 Earth surface emissivity. Constrained to 100 wn to 1500 wn. For CO2 the windows between 2 wn and 100 wn, and 1500 wn and 2200 wn are transparent. But this is not true for water vapor.

curiousd at 09:57 AM on 9 April 2017

Science of Climate Change online class starting next week on Coursera

In order to proceed further with my corrections to Modtran Infrared Light in the Atmosphere (MILA) I need to include some background material. Here are results for OLR of CO2, only greenhouse gas, U.S.standardatmosphere Modtran. I use SpectralCalc atmospheric paths radiance calculator, looking down. A virtual source is on the Earth's Surface, operating between the 500 wn and 850 wn of the CO2 bending mode. Temp 288.2 K, emissivity 0.98 to match Modtran. In addition to the 500 - 850 wn window the transparent (for CO2, although not water vapor, this will come up later) bands between 100 to 500 and 850 to 1500 wn are included, again to match MILA conditions. The "diffusivity approximation" as described, for instance on the Science of Doom website in part 6 of "The Equations" under the Greenhouse Effect, is used with an effective 54 degrees angle to the vertical to go from upward intensity to OLR with units of w/meter squared. It is not a good match to SpectralCalc to actually use angled paths, for one thing the angled paths in SpectralCalc are "real" paths which are strongly refracted. The "diffusitivity" approximation needs idealized straight line paths. In expressions for the optical thickness the factor q/cos theta always appears, where q is a concentration of the GHG, which in the case of CO2 can be considered constant up to 100 km. Say theta was chosen to be 60 degrees. Since cos 60 degrees is (1/2) the factor q/cos 60 = 2q/cos0.

Therefore one just needs to keep a vertical path and multiply the concentration by 2. In my case I use an effective angle to vertical of 54 degrees and multiply the q by 1.7. Modtran actually integrates over the output angles from 0 to 180 degrees. I calculate for a vertical path with q = 683 ppm for CO2 to compare with Modtran for 400 ppm. Below are the results in the next post.

Evan at 09:12 AM on 9 April 2017

Elevator Pitches - Chapter 02 - Radiative Gases

Anything that increases the translational, rotational, or vibrational energy of a molecule will increase its temperature. Energy added to one storage mode (e.g., vibration) is redistribted to the other storage modes until they are all in equilibrium. This happens within a time scale so small that for most considerations it is instantaneous.

John Hartz at 04:31 AM on 9 April 2017

Clouds provide negative feedback

Speaking of clouds and manmade climate change, here’s a handy reference document recently published by the WMO…

Humanity has a primordial fascination with clouds. The meteorological and hydrological communities have come to understand through decades of observation and research that cloud processes – from the microphysics of initial nucleation to superstorms viewed from satellites – provide vital information for weather prediction, and for precipitation in particular. Looking at clouds from a climate perspective introduces new and difficult questions that challenge our overall assumptions about how our moist, cloudy atmosphere actually works.

Clouds are one of the main modulators of heating in the atmosphere, controlling many other aspects of the climate system. Thus, “Clouds, Circulation and Climate Sensitivity” is one of the World Climate Research Programmes (WCRP) seven Grand Challenges. These Grand Challenges represent areas of emphasis in scientific research, modelling, analysis and observations for WCRP and its affiliate projects in the coming decade.

Understanding Clouds to Anticipate Future Climate by Sandrine Bony, Bjorn Stevens & David Carlson, Bulletin nº Vol 66 (1) – 2017

jgnfld at 01:30 AM on 9 April 2017

Sea ice falls to record lows in both the Arctic and Antarctic

Volume always keeps increasing for a while after the extent peak. Yet volume has never been so low at this point in the cycle. Why do you argue that increasing volume in April means there is nothing to worry about re. overall volume?

macquigg at 01:10 AM on 9 April 2017

It's not bad

Eclectic @ #372: It is viewed from the point of view of the human race...

Yes, that is the easy part. Rising sea levels are clearly bad. Worse heatwaves, droughts and floods are clearly bad. The hard part is knowing whether the effects will be good or bad, and if bad, what is the cost of adaptation compared to giving up fossil fuels.

We have to look at the effects one-by-one:

1) Sea level rise. Clearly bad, but we have a few decades to adapt. Do not rebuild in the flood zones of New Orleans. Do some careful planning on the costs of relocating Miami, lower Manhattan, etc.

2) Average temperature rise. We have a few decades for a migration to cooler areas.

3) Shifting climate patterns. This seems like the biggest worry, because it can happen rapidly, and rapid change can be costly.

I think we make a mistake by assuming all shifts will be in a bad direction. I live in the Southeast part of Arizona, and the hot summers here have been getting milder on the eastern edge of the Sonoran Desert. Over a larger area (California and Arizona) the drought is getting worse. A few more years, and the Tucson area could be cut off from its life supply, water from the Colorado River. That would be an economic disaster, and it could happen in just a few years. The resulting collapse in the real estate market could happen instantly.

scaddenp at 12:36 PM on 8 April 2017

We're heading into an ice age

"should be a caveat that those Pliocene-Pleistocene Series precursors to our current situation had to have had both non-anthropormorphic entrances to and exits from their warm periods."

I am not quite sure I follow you, especially with regard to entrance/exit of warm periods. In very broad terms, CO2 has been falling right through the Cenozoic, with exception of PETM. In transition from Pliocene to Pleistocene, CO2 (and surface irradiation) had fallen to level where Milankovich cycles could drive an ice-age cycle. Prior to then, climate was too warm (and CO2 too high). Noone is disputing that orbital forcings drive the Pleistocene ice ages, though turning variations in albedo at 65N into a global event involves several feedbacks of which CO2/CH4 feedbacks are very important. These are hardly analogues of current situation. The pace of change for a start is orders of magnitude faster. If we keep warming, we will also get carbon cycle feedback enhancing the warming but not for 100s of years.

Perhaps time to look at "Climate has changed before" article as well? Or have I completely misunderstood you?

nigelj at 12:01 PM on 8 April 2017

Inconceivable! The latest theatrical House 'Science' committee hearing

Chriskoz @18, the hearings on climate change involving Mann reminds me of a "kangaroo court" that is one of your Australian expressions, for a jacked up court with bad rules, and stacked to ensure a certain result!

Trump sure likes to use his right to free speech. He forget's that with free speech (and I'm a big supporter) comes responsibilities for accuracy, fairness, honesty. He obviously couldn't care less, or is so dumb he just doesn't get it. For democracy to work optimally, it requires people understand both rights and responsibilities.

chriskoz at 10:38 AM on 8 April 2017

Inconceivable! The latest theatrical House 'Science' committee hearing

Tom Curtis@17,

Indeed, your "multitude of sins" is happening in US (also to the lesser extent in other democracies such as Westminster system) and the sinners are largely immune. I'm not talking about people in power abusing their parliamentary priviledges but about ordinary people. Example: the libel lawsuit by Michael Mann against National Review is going on for many years and not proceeding. NR are citing First Amendment in their defence, so far successfuly. It's no brainer to most people who understand the case that it's a classic example of obstructing the truth with an intention to defame by NR, and the judgement in favour of Mann should be swift, yet under the strong protection of First Amendment, NR are still avoiding the penalty.

Your definition of freedom "implies that the choices in electing are free", and access to free and objective education, which, if I understand your point, means self-correcting process similar to scientific discourse be applied to all other discourses of life, esp. political discourse. We are clearly seing that it does not happen in the real world, and US in particular. The funders of First Amendment conceived it to protect defendants in cases like Mann vs. NR. But nothing was invented to protect people against fake news we are experiencing today. Funders thought if people are given unlimitted free rights to discuss whatever they like (but no obligation to stand behind their words and no penalties for failing to do so), the objective truth would emerge from the discussion. Obviously, it did not work and culminated in total erosion of GOP from reality. Yet, amazingly, they're still functioning (togethr eith their President!) and call themselves democraticaly elected representatives, according to Constritution.

They're still spreading blatant lies to the public. The very setup of the hearing we're looking at, is a blatant lie: 1 mainstream scientist (Mann) vs. 3 "sceptics", while the real setup according to the available evidence should be 30:1. And they get away with this lie because of their parliamentary priviledge and First Amendment. And uneducated people continue having a wrong picture that there is still a signifficant uncertainly on th etopic of AGW. I haven't watched the hearing (no time) so one thing I don't understand while Mann did not raise this false balance lie to the microphone. That would be his "biggest moment" if he did. Yet from what I know he complacently answered the same questions as he did 15-odd years ago, as if he accepted the false setting of that discussion. Likely the procedural restrictions did not allow him to say anything but stick strictly to the questions. Well, he could have broken that procedure in the name of the 'freedom' in your sense, yet he chose not to. He was likely so compromised by the procedures, that I suspect even First Amendment would not protect him. We might even talk about a suppression of truth in this case.

Tom Curtis at 10:00 AM on 8 April 2017

We're heading into an ice age

Dave Martsolf @379, carbon cycle models have shown that a significant portion of the excess CO2 in the atmosphere will be retained for many thousands of years. This has been illustrated, along with the relevent processes for drawing down CO2, by David Archer:

The important thing here, however, is not so much the retained fraction as the rate at which CO2 is drawn down, which approximately matches the rate at which temperatures approach equilibrium with a constant CO2 concentration. The approximate match of the rates means that with zero emissions, temperatures remain approximately constant:

That means that if we were to eliminate all CO2 (and other greenhouse) emissions over night, we could expect an equilibrium temperature of 1 C above the preindustrial. If we allow cumulative emissions 1000 GtC before ceasing all emissions, we could expect an equilibrium temperature of 2 C. On current policy settings, the stable temperature will be at least 3 C, if achieved at all (it only requires 5-10% of current emissions to result in a constant, or even slightly rising concentration, and no policy pursued by any government currently pursues zero emissions).

Those estimates hide a host of details. For instance, while GMST will be approximately constant with zero emissions, ocean temperatures will continue to rise for a short period, while land temperatures fall slightly. Sea level will continue to rise, both because of the rising ocean temperatures and because the ice sheets will melt back in the face of the constant elevated temperatures.

Jim Hunt at 07:41 AM on 8 April 2017

Sea ice falls to record lows in both the Arctic and Antarctic

Chris @2 - Although Arctic sea ice extent has passed it's maximum for this year, volume is still increasing. The situation is bad, but not as bad as you're suggesting!

The September average volume in 1980 was just over 16 thousand km³.

Yail Bloor at 05:01 AM on 8 April 2017

We're heading into an ice age

DaveMartsolf, concerning CO2 residence time, warming potential can last centuries.

It is true that an individual molecule of CO2 has a short residence time in the atmosphere. However, in most cases when a molecule of CO2 leaves the atmosphere it is simply swapping places with one in the ocean. Thus, the warming potential of CO2 has very little to do with the residence time of CO2.

CO2 emissions change our atmosphere for centuries

DaveMartsolf at 04:54 AM on 8 April 2017

We're heading into an ice age

As a second comment I was intrigued by scaddenp's first link in the discussion above, a link to John Mason's 2013 post regarding past geologic records of 400ppm CO2 found in Russia's Lake E, referred to as a super-interglacial, and ending with the query, is this what we are headed for? Likely, the answer is yes, but as I mentioned above there should be a caveat that those Pliocene-Pleistocene Series precursors to our current situation had to have had both non-anthropormorphic entrances to and exits from their warm periods. If the earlier entrance to the 400ppm plus CO2 atmosphere happened as relatively quickly as ours has, then that past cycle might mimic ours. Does anyone reading this know if the record shows that the CO2 level changed that rapidly, perhaps as the result of some extraterrestrial fireball such as created Lake E and may have burned up all flora on the planet within several years or less? My apologies for being so uninformed in these things. But, I am so curious.

curiousd at 02:45 AM on 8 April 2017

Science of Climate Change online class starting next week on Coursera

Correction number one:

Consider the following settings for "Modtran Infrared Light in the Atmosphere" (MILA)

1. All greenhouse gas concentrations set to zero.

2. 1976 U.S. Standard Atmosphere.

3. Looking down from 70 km

4. Temperature offset at minus 33.2 K, giving a grount temperature of 255 K.

The out going long wavelength radiation (OLR) is then given by MILA as 225.075 W/meter squared.

From the "Black Body Calculator" of SpectralCalc, at 255 K, emissivity 0.98, in the 2 wn to 100 wn range the band radiance (SpectralCalc terminology) is 0.554602 W/meter squared steradian. Multiply by the pi available steradians of a Lambertian surface to obtain a flux of :

(a) 2 wn to 100 wn outgoing flux of 1.742 W/meter squared.

By a similar procedure for 1500 wn to 2200 wn one obtains

(b) 1500 wn to 2200 wn flux of 6.3437 W/meter squared

Then for the 0.98 emisivity case the corrected MILR output is 225.075 plus 1.742 plus 6.3437 = corrected flux of watts/meter squared of 233 watts/meter squared. This is what one obtains by using an expanded wave number range from 2 wn to 2200 wn, assuming emissivity of 0.98.

If instead of an emissivity of 0.98 one uses an emissivity of unity then by a similar procedure one obtains a corrected output flux of 1.777 w/meter squared plus 231.144 watts/ meter squared plus 6.473 watts /meter squared equals 239 watts/meter squared. Note that here the output of MILA between 100 wn and 1500 wn is changed from 225.065 watts / meter squared to 231.144 watts per meter squared to correspond to emissivity of one instead of the MILF emissivity of 0.98.

The context of these results is the following: A number of treatments of elementary environmental science, such as written, for instance by Archer or by Wolfson, show that an Earth with no greenhouse effect, but assuming a best estimate of cloud albedo, is in thermal equilibrium with incoming solar radiation if the average Earth surface temperature is quite close to 255 K. This temperature corresponds to an OLR of 239.7 watts/meter squared for thermal IR emissivity of one, by using the Stefan-Boltzmann law. The best value from sophisticated satellite analysis for the top of the atmosphere by Trenberth, Fasullo, and Kiehl, BAMS 90, 2009, 311 - 323 is 239 watts/meter squared. These authors assume an emissivity in the thermal IR for the Earth's surface of 1.0.

I will wait to see if others accessing Skeptical Science and reading this post believe my analysis is correct or not, before posting my next correction which is for the value of the cloud free earth OLR.

curiousd at 01:22 AM on 8 April 2017

Science of Climate Change online class starting next week on Coursera

The underlying Planck distribution for the free website "Modtran Infrared Light in the Atmosphere" is displayed in the user output for a range between 100 wn and 1500 wn. I have accidentally found out that this wavenumber range is not just a graphical convenience. The underlying program does have this somewhat limited wavenumber range.

If one investigates the output of the "Show Raw Model Output" button, two features become evident:

1. The underlying computer program does really have a range limited to 100 wn - 1500 wn.

2. The underlying computer program assumes an earth surface emissivity of 0.98.

I have developed corrections to "Modtran Infrared Light in the Atmosphere" for several fundamental cases. The corrections could be made to a class by verbal instructions and do not require any re-writing of the program.

I submitted an authorship proposal to the "Bulletin of the American Meteorological Society" (BAMS). The suggestion of the Board of Editors of BAMS is the following:

"Your corrections to Modtran sound promising for a wide audience. However, the editors feel that BAMS is not the appropriate venue for vetting and distributing this information. For proper exposure and discussion, they would be more productively disseminated directly within the Modtran user community online." In the spirit of the suggestion of the BAMS editors I post below the first of my corrections.

Moderator Response:

[JH] Embedded url into free website "Modtran Infrared Light in the Atmosphere".

DaveMartsolf at 23:36 PM on 7 April 2017

We're heading into an ice age

Yes, I was joking on that point and understood on the 1000s of years time required to melt all the ice.

But, don't all these forecasts assume some type of elevated CO2 presence for years to come? I understand that even the most hopeful time scale for full conversion from fossil fuels to renewables with or without the nuclear option is still estimated to be many years away, but I do believe this will happen, and sooner than many people predict today. As that happens, and as we figure in the relatively rapid natural sequestration of our currently elevated atmospheric CO2 levels (half life in the order of only 20-30 years), I still wonder what the models will show when ocean temperatures have been elevated through all the current (and perhaps for another 50-100 years into the future) CO2 emissions to rather suddenly find their warmed surfaces evaporating into crystal clear skies that can quickly radiate all that heat (but not the moisture) into space. It will be a unique set of conditions not often seen on the planet.

Skeptical Wombat at 17:45 PM on 7 April 2017

Sea ice falls to record lows in both the Arctic and Antarctic

But the message from scientists is that while Antarctic sea ice appears to be bucking the trend this year, they need more than a single year before they can tell if a long-term change is afoot.

True, but the fact that the total increase over the last 38 years has been totally reversed is an indication of just how small that increase has been. Imagine the uproar in the denialsphere if minimum arctic sea ice extent was to reach a maximum for the sattelite era. Moreover using linear regression the rate of increase in average March extent in the Antarctic over the sattelite era is no longer statistically significant.

Tom Curtis at 15:16 PM on 7 April 2017

Inconceivable! The latest theatrical House 'Science' committee hearing

chriskoz @16:

"Our disagreement is most likely the result of different understanding of the word "democracy". Hence my understanding of democracy is at the very basic level:
'government by the people; a form of government in which the supreme power is vested in the people and exercised directly by them or by their elected agents under a free electoral system.'"

That definition covers a multitude of sins. To start with, what is meant by "free". To me it implies that the choices in electing are free. But an uninformed in ill informed choice is not free, in the relevant sense. On the first basis, it is widely held that you cannot have a genuine decomacracy without free speech. It should also be held, on the same basis that you cannot have a genuine democracy where the citizens are poorly educated (as is the case in much of the US). On the second basis, widespread reporting of 'fake news' such as by Breitbart or Fox News impars the democracy, as does the continuous lying by Trump himself. (As an aside, I believe that a person seeking or holding elected office in a democracy, who lies to the people to assist their aim of being elected, has committed treason.)

On the second point, the Electoral College is not so constituted that it will typically reflect in its membership the proportion of votes for each candidate. That means their claim to be elected representatives is dubious to start with. That claim is further weakened given that the number of electors in the electoral college for each state is not proportional to the number of citizens eligible to vote in each state.

On a more technical point, supreme power is not vested in the Electoral College, but in the President. The President is neither the people, nor an elected agent of the people; but rather an elected agent of the electoral college.

Given the mendacity with which he campaigned, the active interference of foreign powers, the active interference of non-citizens in the form of corporations, the barstadized rules governing elections to the Electoral College, and that he did not secure a plurality of votes, Trump's claim to be democratically elected is just another of his lies. He is President, but that is because the rule of law is an even more fundamental principle of good government than is democracy.

chriskoz at 14:20 PM on 7 April 2017

Inconceivable! The latest theatrical House 'Science' committee hearing

bjchip@12,

Our disagreement is most likely the result of different understanding of the word "democracy". Hence my understanding of democracy is at the very basic level:

government by the people; a form of government in which the supreme power is vested in the people and exercised directly by them or by their elected agents under a free electoral system.

In US, the elected agents are state electoral college system. And it works precisely to the above definition.

That the outcome of the system is not the one that Jefferson envisaged, is a different issue.

If you take a more specific definition, e.g. "political or social equality", you may argue that US electoral college system has failed because it produced an absurd outcome despite a broad "political equality" (popular vote) disagreeing with the result, favouring Clinton.

Or if you take another angle of the definition, e.g. "people of a community as distinguished from any privileged class", you may argue that democracy has eroded because special interest groups (FF or other vested interests) have created the rules (e.g. electoral college boundaries) where they maximize their voting gains, they also (e.g. via control of mass media) supress the "inconvenient" science and brainwash people who are deceived into voting the candidates that do not represent their interests.

But that would be your definition of democracy. And I would agree if I accepted it but I don't accept it in this context. I just say that the US democracy is working as it's supposed to work. No doubt it would work differently (maybe better and did not produce an absurd outcome as it did this year) if it was changed. If Jefferson was alive he would likely want to change it, too.

It turns out we have a lot in common: I have also done a move identical to yours. I moved from US over a decade ago (to Australia so almost the same), one of the reasons of my move was the reality of US politics and social life were not entirely to my liking.

Dennis Horne at 14:15 PM on 7 April 2017

Inconceivable! The latest theatrical House 'Science' committee hearing

Michael Mann was ambushed. He walked straight into the Clay Higgin's trap (Association of Concerned Scientists, Climate Accountability Institute). A minute on Wikipedia and youtube ("Don't Be Throwing Rocks - Congressmen Clay Higgins") and he might have known not to answer. (Copy Judith Curry: "We don't know".)

Elizabeth Esty knew what was going on and how to deal with it. You can't argue with Lamar Smith, you go around him.

The fundamental problem is the person speaking for science has to know everything in the book and a denier needs know only one question, which may not have a simple answer. So a scientist is going to come off second best against a lawyer or politican.

It is a game and maybe there is something to be said for not playing.

bjchip at 13:06 PM on 7 April 2017

The Myth of 'Clean Coal'

One has to be realistic about what they mean when they say "clean".

http://www.businessinsider.com/ap-pride-vies-with-sadness-as-britains-last-coal-pit-closes-2015-12?IR=T

I don't think it means what they think it means :-)

Moderator Response:

[PS] Fixed link. Please learn do it yourself with the link tool.

laurencerhunt at 13:03 PM on 7 April 2017

Trump has launched a blitzkrieg in the wars on science and Earth’s climate

I post regularly on climate change topics because global warming is on track to change almost everything we take for granted about Earth's climate. That said, Mr Trump will be gone in a few short years, and Mar a Lago will be spongy wet and under water soon thereafter.... What I'm concerned about, and I think the distinction is important, isn't "stopping" carbon burning... Rather, what interests me is no longer needing to burn any carbon at all. In my view, humanity should be 100% focused on only that aim. Anything else takes us off-track. If we had invested only what has been poured down the rathole of fracking, we would likely have fusion power today, and be on the way to a fusion-powered grid now.

nigelj at 11:37 AM on 7 April 2017

Inconceivable! The latest theatrical House 'Science' committee hearing

Good article, but I struggle with a political article that then says don't post political comments. Doesn't make sense.

Some moderation is very good and improves the signal to noise ratio, too much will deter anyone from posting anything, and strays into censorship.

Moderator Response:

[PS] Moderators find this incredibly tough too. Rules are more relaxed on political threads but firing off partisan insults is still going attract moderation. "All republicans are stupid" or "All democrat are secret commies" dont contribute anything to discussion. Criticism needs to be specific, factual (and referenced if an assertion is being made) to make a worthwhile discussion.

nigelj at 11:05 AM on 7 April 2017

The Myth of 'Clean Coal'

www.washingtonpost.com/national/health-science/coal-is-king-among-pollution-that-causes-heart-disease-study-says/2015/12/01/3fb88194-9840-11e5-8917-653b65c809eb_story.html?utm_term=.67896903cabf

This research finds coal is a much larger factor in heart disease than previously realised.

Clean coal is never going to happen. Firstly clean coal would require very, very expensive systems to filter particulate emissions, and filter and bury the carbon dioxide, and it doesn’t make sense to do this, as there are more cost effective alternatives with gas or renewable energy already available.

And the only way to get clean coal would be government regulation making this cleaning process happen. The Trump Administration is never going to regulate to ensure they have clean coal. Trump has an open agenda to reduce regulation, and which has already acted against all sorts of environmental initiatives. Clean coal is another illogical and empty promise that won’t happen, just like other recent policy failures.

scaddenp at 10:13 AM on 7 April 2017

Inconceivable! The latest theatrical House 'Science' committee hearing

Trump is doing the inconceivable - making NZ politicians look good. I didnt realize how good parlimentary systems are. Wonder when US congress will get a headline like this: Government surplus almost $1 billion ahead of forecast as business profits boost tax take

bjchip at 09:29 AM on 7 April 2017

Inconceivable! The latest theatrical House 'Science' committee hearing

Sorry about the caps, I learned to do this before there was a convenient way to bold a comment... :-)

Chriskoz@2 - I disagree. To have Smith and other anti-science pro-ignorance people and parties being elected is a symptom. The role of ignorance in the demise of a democracy was understood by Jefferson

"If a nation expects to be ignorant and free in a state of civilization, it expects what never was and never will be" - Jefferson

...and has not changed. It takes people who are ignorant to elect people who are ignorant, and ignorance is caused by a failure of the news and the schools to inform people who have been transformed into consumers rather than active participants in the governance of the country. The news is not required to be accurate, it is required to gain viewers and sell advertising. The "Free Market" is in fact, the rope with which the Capitalists hanged us all. Recognition of its limitations has never been a common thing in the USA.

Which is why Smith is a symptom, not a cause, of the problem.

He and the T-rump are symptoms and as reprehensible as they are, one has to look for the root cause of this problem and work through the solutions available.

I did that and moved to New Zealand over a decade ago :-)

I still think that any action by the scientific community alone will fail. Contempt of Congress is what you get with a "failure to appear" and that's not a reasonable risk for a man with a family. I think that instead the action has to be broader and more definite. The nation is more divided, more polarized, than it has been at any time since the Civil War. The people who have done that to it are now "in power" and have promised more and greater errors.

There comes a time when one simply has to leave.

"When in the Course of human events, it becomes necessary for one people to dissolve the political bands which have connected them with another, and to assume among the powers of the earth, the separate and equal station to which the Laws of Nature and of Nature's God entitle them, a decent respect to the opinions of mankind requires that they should declare the causes which impel them to the separation." - Jefferson

The choices available are pretty stark.

chriskoz at 09:26 AM on 7 April 2017

Sea ice falls to record lows in both the Arctic and Antarctic

CBDunkerson@2,

yearly max volume now is roughly equivalent to where the yearly min volume was in 1980
a continuing linear trend [...] would result in the Arctic being nearly ice free year round by ~2060

Not quite. First, you're exagerating. I read the min in 1979 (grey line) was 14k km3, while Jim quotes today's max at 20. So max has still awhile to drop to reach 14.

Second, remember we're talking about volume reconstruction, rather than area. Volume may drop to near zero but area may stay large if ice becomes simply thinner. So, arctic will not be simply ice-free.

Third, even if summer minimum drops to zero for an extended period of time (likely by mid-century) it does not take much of winter cold to freeze over large part of arctic. Irt's enough that the temps drop below 0C which will be happening for many years ahead, certainly the whole century.

Finally, if you look at IPCC sea ice projections, the downward trajectory will deflect and flatten in the second half of the century, so the exponential/linear process of ice loss will reverse, I think for the reasons I noted in third.

scaddenp at 07:34 AM on 7 April 2017

Inconceivable! The latest theatrical House 'Science' committee hearing

I thought Titley did rather well in the bits I heard from last inquisition. Personally, I would have liked to see Schmidt or Alley there.

scaddenp at 07:13 AM on 7 April 2017

We're heading into an ice age

Wouldnt get your hopes up. You can get 70m (230') by melting all the ice, but melting all of EAIS and GIS would take 1000s of years.

However even 1m of sea level rise would displace a couple hundred million people who are not so fortunate in their location.

DaveMartsolf at 06:41 AM on 7 April 2017

We're heading into an ice age

Wow! Thanks for all the feedback everyone. You are so kind. I will review all this new data and if I have any further questions I'll jump back in. This is a real learning experience for me. Thanks again.

Looks like we're in for warmer weather. We live at about 300' altitude in New Hampshire. I've told our daugher to hold onto the property as it will likely become beachfront generations down the road.

nigelj at 05:54 AM on 7 April 2017

Sea ice falls to record lows in both the Arctic and Antarctic

Yes the arctic is likely to be ice free within many peoples lifetimes. However Russia, America and Canada and some smaller nations may see this as an economic opportunity. It's no coincidence the USA and Russia in particular are sceptical of causes of climate change, and another reason for Trump and Putin are so friendly.

There are multiple business agendas going on here, and personal interests and beliefs being promoted. They don't see that the planet could get wrecked in the process. Some people are short term thinkers and huge risk takers, and will gamble anything to the detriment of everyone else.

www.cfr.org/arctic/thawing-arctic-risks-opportunities/p32082

John Hartz at 02:37 AM on 7 April 2017

Inconceivable! The latest theatrical House 'Science' committee hearing

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