By Dr. Roger Pielke Sr.
Andy Lacis has posted two guest contributions on my weblog;
Guest Post “CO2: The Thermostat That Controls Earth’s Temperature” By Andy Lacis
Further Comment By Andy Lacis On CO2 As A Climate Thermostat
I very much appreciate this collegial interaction.
Today, I want to comment on his conclusions.
First, I agree with Andy’s conclusion that if CO2 were removed from the Earth’s atmosphere, the climate system would rapidly cool. I also concur that CO2 is a first order climate forcing and is a non-condensing greenhouse gas forcing.
The more interesting question, however, is how this applies both to how the Earth’s climate system actually evolved, and how incremental increases in CO2 above what was present in pre-industral times alter the climate.
With respect to the early Earth atmosphere, CO2 was emitted from volcanic eruptions but so was water vapor. The two acted together to warm the climate. Indeed, this is one explanation proposed to explain the warm, wet period in the earlier atmosphere of Mars and Venus. While, the model experiment presented by Andy and colleagues is quite interesting, it does not reflect the real climate system.
The second issue is, of course, directly relevant to our future climate. As I posted in
we have examined the effect of incremental increases in CO2 (and water vapor) as described in detail in
Relative Roles of CO2 and Water Vapor in Radiative Forcing
Further Analysis Of Radiative Forcing By Norm Woods
In regards to the effect of an incremental effect on radiative flux of an increase in the atmospheric concentration of CO2, there is an informative figure at Watts Up With That in a post by David Archibald titled The Logarithmic Effect of Carbon Dioxide. The figure is from 2006 by Willis Eschenbach which was posted on Climate Audit.
What is of importance to our future climate is the added downwelling radiative fluxes as given by the green and black lines. The Lacis and colleagues study examined the effect of the radiative forcing from red line.
The issue with respect to our future climate is how will it be altered in response to these incremental increases, part of which (particularly in the humid parts of the world) overlaps with water vapor absorption).
In terms of how environmentally and societally important resources are altered, as I have often posted on (e.g. see), in terms of climate, this involves how droughts, floods, tropical cyclones, heat waves, etc are altered. This means the focus should be on alterations in regional ocean and atmospheric circulations, mesoscale weather patterns, and so forth rather than on trends in the global average surface temperatures. The addition of CO2 is one factor (both radiatively and biogeochemically) but is not the single ”control” of these climate metrics.
The equilibrium temperature of Earth is just one of these metrics, and, indeed is not adequate to explain how regional and local climate could change. In fact, even with respect to global warming and cooling, the use of ocean heat content is a much more robust way to diagnose these climate system heat changes than a global average surface temperature trend, as discussed most recently in
Pielke Sr., R.A., 2008: A broader view of the role of humans in the climate system. Physics Today, 61, Vol. 11, 54-55.
Andy’s posts (and paper) do clearly show that
“ there is a clear demonstration that without the radiative forcing provided by the non-condensing GHGs, the terrestrial greenhouse effect collapses because there is no structural temperature support to restrain the current climate water vapor from condensing and precipitating.”
However, there needs to be a recognition that the human influence on the climate system, including global warming and cooling, involves much more than the non-condensing greenhouse gases, and that the role of natural climate forcings and variability remain incompletely understood. We have discussed this in our paper
Pielke Sr., R., K. Beven, G. Brasseur, J. Calvert, M. Chahine, R. Dickerson, D. Entekhabi, E. Foufoula-Georgiou, H. Gupta, V. Gupta, W. Krajewski, E. Philip Krider, W. K.M. Lau, J. McDonnell, W. Rossow, J. Schaake, J. Smith, S. Sorooshian, and E. Wood, 2009: Climate change: The need to consider human forcings besides greenhouse gases. Eos, Vol. 90, No. 45, 10 November 2009, 413. Copyright (2009) American Geophysical Union.
I invite Andy to discuss where he agrees, and where he disagrees, with our conclusions and recommendations in the above paper.
Tokyoboy,
That tide gauge study is very interesting. It appears to track the NH temperature for that period very well.
…….” if CO2 were removed from the Earth’s atmosphere, the climate system would rapidly cool”……………………..
Who says we need to remove the CO2?
The true subtraction test for GAGW is much simpler.
Everything remains the same except that CO2 does not absorb/radiate in the infra red.
What difference would that bring about?
I would think very little if any.
The first graph here is headed ‘Modtrans results.’
I’m sure Ive seen this diagram with the actual temperature rise that should ensue shown. It wasn’t in the links so can anyone here point me to it?
Tonyb
No!!
There is no account of the warming through adiabatic heating of atmospheric gasses. If the useless GHG theory(hypothesis) is ignored and adiabatic heating taken into account the GHG hypothesis can go.
Dr Pielke Sr. has ignored the fact that during the Ordovicean period atmospheric CO2 levels were in excess of 8000ppmv and there was a severe ice age.
When the earth formed the proto-atmosphere was in excess of 20% CO2 for the simple reason that there was no process then available to produce oxygen. This was started by the cyanobacteria and taken over by plants using photosynthesis. This was around 2.5 billion years BP. Since then atmospheric CO2 levels have varied to today’s dangerously low leveld of 385ppmv, if we are to believe the NOAA figures.
Dr Pielk seems to forget that plants thrivce in high CO2 levels and will die at atmospheric levels below 200 ppmv. All life on earth came from atmospheric CO2 and this gas is vital gfor life to continue.
As far as acting as a thermostat CO2 does no such thing. This vital action is carried out by water vapour and clouds which some climatologists are just now realising.
Mike says:
November 11, 2010 at 9:58 pm
“It is well known the the main problems posed by global warming on land is not the higher temperature per se but the concurrent changes in rainfall patterns and possible sea level rise.”
It is also well known that the main benefits offered by global warming are increased productivity of primary producers in the food chain, more efficient fresh water utilization by terrestrial plants, warmer nights, warmer winters, and a greater margin of safety keeping the interglacial period from flipping back over into the glacial period of the ice age the earth has been in for the past few million years.
I haven’t seen a shred of evidence that indicates global warming is not a huge net benefit for life on the earth and plenty of indisputable testimony from the geologic column that the biosphere blooms mightily when CO2 levels are far higher and global average temperature 8C warmer.
Before I consider any mitigation as anything other than pure unadulterated stupidity someone has to demonstrate first that warming and higher CO2 is a bad thing. Good luck with that because the clear evidence of the history of this planet shows us that a warmer earth is a greener earth and a colder earth is a deader earth. Personally I prefer my earth warm and filled with plants & animals rather than barren and covered with ice. Ice huggers are nutjobs.
RE: Eric Anderson:( November 11, 2010 at 11:48 pm )
“Exponential increase in CO2? Is the rate of increase exponential? I’d like to see some support for that…”
That might be based on an assumed exponential growth of human population. In the last 40 years of the 20th century, the human population doubled. If that continues for 1000 years with 25 doublings, they would have to find living space, food, and energy for over 33 million times the current population of the earth…
This is all good theoretical stuff that can keep endless numbers of climate scientists going for long enough. I wish someone would urgently address why CO2 keeps going up but global temperatures remeain basically steady since 1998 with small variations from year to year http://www.drroyspencer.com/latest-global-temperatures/ and we are probably not getting “the hottest year ever” as predicted in the summer by the “warmers”. Global sea levels are dropping http://sealevel.colorado.edu/current/sl_noib_global.jpg and Argos will not release latest ocean temperatures (believed because they are dropping). From the WUWT sea ice page it is obvious that combined n/s sea ice is within natural variation. I scratch my head and wonder why the climate science community is not focusing on explaining these measured facts. CO2 is going up but the major indications of rising heat in the system such as air and sea temperatures are steady or maybe falling. Global sea levels are falling and sea ice remains basically steady. These are major issues requiring to be addressed. To me as a non scientist it means there are other forcings (and maybe negative feed-backs) that overwhelm CO2. What about an explanation ordinary people can understand????
tonyb says:
November 12, 2010 at 2:19 am
Modtrans output cannot be translated to temperature change without an assumption that everything else remains the same. The only certainty about everything else is that it won’t remain the same. Modtrans examines single easy-to-calculate factors in isolation. In the real world these factors are not isolated. For instance modtrans won’t reveal that forcings in the real world aren’t distributed equally. In the real world when we have additional forcings they are concentrated in times and places where forcings are minimal – higher latitudes get more of the net forcing increase than lower latitudes, winters get more than summers, and nights get more than days.
And even that’s questionable as additional forcing from a well-mixed non-condensing greenhouse gas might very well just result in reduced forcing from the condensing greenhouse gas (water vapor). In fact the best evidence points to exactly that response. Once you have enough non-condensing greenhouse gases in the atmosphere to raise the average surface temperature above freezing then the condensing greenhouse gas takes over from there. My major concern is that 280ppm CO2 is factually not enough non-condensing greenhouse gas to keep the earth from entering an ice age. It would be great if we could end the ice age by burning fossil fuels but I fear there aren’t remotely enough recoverable fossil fuels to do that. The future for human civilization is rather grim looking following the end of the Holocene interglacial.
Bryan says:
November 12, 2010 at 1:39 am
A deeply frozen planet. The average temperature of the moon is -23C and its albedo is around 15%. A snowball earth would have an albedo of 85% and would thus be far colder than the moon. Greenhouse gases are the only thing that prevents that from happening. Water vapor is by far the major greenhouse gas but it is a condensing gas and once it condenses out into snow there is nothing but greenhouse effect from non-condensing gases to melt it.
Dave Springer
If the only change to the Earths atmosphere was that CO2 did not absorb/radiate in the IR we would end up with a ….”A deeply frozen planet. ”
Water vapour can still absorb/radiate in the IR.
We still have Oceans
We still have an atmosphere.
……”Water vapor is by far the major greenhouse gas but it is a condensing gas and once it condenses out into snow there is nothing but greenhouse effect from non-condensing gases to melt it.”……
Would snow fall on the Oceans?
The absence of a radiative effect of CO2 would suggest that the Earth would warm slightly more during daylight and cool slightly more at night.
Mike Borgelt says:
November 12, 2010 at 12:17 am
Huh? Mars is cold because sunlight there is less than half the intensity as it is on the earth. Venus is hot because sunlight there is nearly twice the intensity as it is on the earth. All three planets have essentially the same composition – rocky worlds which all formed at the same time from the same dust cloud. The only thing essentially different between the three is distance from the sun and in the end that’s all that matters.
“First, I agree with Andy’s conclusion that if CO2 were removed from the Earth’s atmosphere, the climate system would rapidly cool. I also concur that CO2 is a first order climate forcing and is a non-condensing greenhouse gas forcing”
If you remove all the CO2 wouldn’t that kill all vegetation? Doesn’t rotting vegetation produce CO2 and methane? Isn’t methane a greenhouse gas? What then?
O/T but, OMG, Shock!
Horror!
The Guardian, of all people, (promoters of the Thermogeddon snuff movie edu-tainment masterpiece “No Pressure”) are today reporting:
[fanfare]
“It’s better than we thought. In fact, it’s really rather good.”
A new reports seems to show that far from killing it stone dead, global warming may actually be good news for the Amazon.
Go figure.
http://www.guardian.co.uk/environment/2010/nov/11/climate-change-forests-water-amazon
If all the CO2 were removed we would still have all our Nitrogen, Oxygen, trace gases and water vapour plus all our oceans and a continuing hydrological cycle all reacting to solar input just as they do now.
Would that not maintain atmospheric temperatures at much the same level ?
We might see a slightly reduced speed for the hydrological cycle with jets a fraction closer to the equator but what else would happen, all other things remaining equal ?
@ur momisugly 899
I hope you realise how nice people have been to you. Also, that this site does allow wide expression of opinion, a major “plus”, but I guess you came close to being snipped. Just advice.
(The theoretical thesis being explored is that if the temp. dropped below freezing, water vapour would condense out and freeze, greatly lowering the water vapour pressure to the extent that only non condensing GHG (non condensing at those kinds of temperatures) would elevate the temp. above what a “straightforward” Black Body radiation calculation shows the Earth would be at.)
tokyoboy says:
November 11, 2010 at 11:23 pm
. . . Regarding the sea-level change, this is a summary of 105-year monitoring of Japanese tide gauges by our MET:
http://www.data.kishou.go.jp/shindan/a_1/sl_trend/sl_trend_graph.png
Thouh the satellite era data over a short period (from 1992) by the Colorado group agrees fairly well with the above graph, our MET says that “no long-term trend is seen” and “a 20-year oscillation pattern is obvious.”
The Colorado satellite data covers only a rising portion of the oscillation, and if the pattern holds, we’re coming to the end of the 3.1 mm/yr rise, and might even see sea levels start to fall in a couple years. Indeed, the Jason portion of the chart (since 2002) looks to have a shallower rise of 2.5 mm/yr, eyeball calibrated.
Satellite sea level has fallen most of this year, and while we would normally expect it to bounce back up, there is a chance it might level off instead. That would put a serious kink in the catastrophic sea level rise theme.
John Marshall says:
November 12, 2010 at 2:34 am
Actually it’s widely accepted that all life on earth came from heterotrophs which by definition lack the capacity to fix carbon. All the evidence suggests that the young earth was rich in hydrocarbons. The clincher was finding that comets, which are preserved remnants of primordial conditions, are rich in hydrocarbons. These hydrocarbons served as ready-made food for life until they reduced the supply to such an extent that it was either evolve into autotrophs (carbon fixers) or perish. Heterotrophs don’t need sunlight or CO2 they just need liquid water and a food supply. Today we a have rich mix of both heterotrophs and autotrophs neither of which can survive without the other and sunlight is now required to drive carbon fixation since the primordial hydrocarbon food supply has been used up.
I do find all this very amusing. The first time I seriouslt thought about carbon, was not when I picked up my first pencil, but when I heard the term Carbon Infestations in reference to life on Earth, essentially human beings. It was probably on Star Trek or some such. Jo public generally seem to think that Carbon based life forms are human beings, when in fact ALL LIFE is carbon based. CO2 + H2O = basic sugars. I defy amyone to stand on their nearest hill & point to something living that isn’t Carbon based, oh & I want 0.04% of their profits when they do so & become billionaires overnight for such a discovery. I take great delight in irritating hard nosed environmentlists by asking for a carbon based scribbling device to explain my designs & structural forms. I do get some odd looks but I don’t care.
The fact that CO2 changes lag temperature changes in the paleoclimate record is sufficient, in and of itself, to conclusively refute the assertion that CO2 is the climate thermostat.
Hmmm….
Pulling in the added impact of plants and such for a statement of “removing CO2 from the atmosphere” is not applicable. The purpose is to state what the impact would be simply to the surface temperature.
In the humid areas of the world there would be little to no impact to temperature if the CO2 was removed. The non-humid regions would see some cooling. The idea that water vapor would stop existing in the atmosphere is bizarre. The partial pressure of water vapor is not in any way dependent on CO2, it is only dependent on the temperature of the water.
There is a clear misunderstanding as to what the measured down welling radiation actually indicates, much like there is a misunderstanding of the overall impact of radiative heat transfer. That’s ok, I will fix it. 🙂
theinconvenientskeptic.com
Came across this the other day…does it have a reasonable contribution to the discussion? I will try to post the link later.
The atmospheric greenhouse effect, an idea that many authors trace back to the traditional works of Fourier (1824), Tyndall (1861), and Arrhenius (1896), and which is still supported in global climatology, essentially describes a fictitious mechanism, in which a planetary atmosphere acts as a heat pump driven by an environment that is radiatively interacting with but radiatively equilibrated to the atmospheric system. According to the second law of thermodynamics such a planetary machine can never exist. Nevertheless, in almost all texts of global climatology and in a widespread secondary literature it is taken for granted that such mechanism is real and stands on a firm scientific foundation. In this paper the popular conjecture is analyzed and the underlying physical principles are clarified. By showing that (a) there are no common physical laws between the warming phenomenon in glass houses and the fictitious atmospheric greenhouse effects, (b) there are no calculations to determine an average surface temperature of a planet, (c) the frequently mentioned difference of 33 degrees Celsius is a meaningless number calculated wrongly, (d) the formulas of cavity radiation are used inappropriately, (e) the assumption of a radiative balance is unphysical, (f) thermal conductivity and friction must not be set to zero, the atmospheric greenhouse conjecture is falsified.
I wonder what’s a bigger disaster for humanity.
The warmists or the luke warmers.
Link to previous comment is:
http://arxiv.org/PS_cache/arxiv/pdf/0707/0707.1161v4.pdf
Stephen Wilde says:
November 12, 2010 at 4:29 am
For a short while perhaps. The problem is that solar input alone with a rather low natural albedo of 15% is not enough to raise the average surface temperature above freezing. Frozen water has very high albedo so once you get to a point where snow cover grows in duration and extent over time a tipping point is reached where a rapid vicious cycle begins where more snow breeds even more snow with nothing to stop it except non-condensing greenhouse gases. Even so, 280ppm CO2 clearly isn’t enough to stop it in the current orbital configuration and position of the continents as the earth has been in an ice age for the past few million years. It would be great if an anthropogenic doubling of CO2 was enough to break the cycle of 100,000 years of glacial dominance and 10,000 years of glacial retreat but I suspect we can’t sustain the artificial CO2 increase in magnitude or duration enough to accomplish anything more than, at best, delaying the end of the interglacial period. At that point biomass will be greatly reduced with most of it confined to the tropics and most of extant human civilization will be buried underneath miles of ice.
There seems to be a decided lack of long term perspective amongst the CAGW cabal. They’re being penny wise and pound foolish – all worried about preserving the exact status quo of human civilization at this exact point in time while completely ignoring what’s going to happen a few thousand years in the future when the Holocene interglacial period ends. That end is assured unless something comes along to stop it and the evidence is overwhelming that pre-industrial greenhouse gas concentration isn’t enough to stop it.
Richard Dawkins famously said “It is absolutely safe to say that if you meet somebody who claims not to believe in evolution, that person is ignorant, stupid, or insane (or wicked, but I’d rather not consider that)”.
There’s a corollary here in climate change.
It is absolutely safe to say that if you meet somebody who claims not to believe the Holocene interglacial is nearing its natural end, that person is ignorant, stupid, or insane (or wicked, but I’d rather not consider that).
Stephen Wilde says:
November 12, 2010 at 4:29 am
If all the CO2 were removed we would still have all our Nitrogen, Oxygen
===================
I don’t think oxygen would last very long in the atmosphere without CO2, which is almost the sole source of atmospheric oxygen renewal through photosynthesis.
Plants would be gone without CO2. Without plants to renew the oxygen, it should not take long for it to be completely depleted by oxydizing minerals on the surface of the Earth.
Of course a CO2-less atmosphere is rather unimaginable unless CO2 is also removed from the lithosphere. But these discussions are illuminating in their power to highlight the olympic vastness of our ignorance. What transpires from all the diverse opinions is that we don’t have much of a clear idea what the temperature would be do in the total absence of atmospheric CO2, and yet we seriously pretend to be able to calculate the small thermal, if any, effect of small variations in the concentration of this gas.
One might think that testing the thermal effects of a high concentration of CO2 versus zero CO2 in a controlled column of air might be somewhat doable to get at least a rough idea. God forbid! Pure speculation and modelling is so much more fun and freewheeling when not burdened by the vulgarity of empirical endeavors.