NOTE: This has been running two weeks at the top of WUWT, discussion has slowed, so I’m placing it back in regular que. – Anthony
UPDATES:
Statistician William Briggs weighs in here
Eduardo Zorita weighs in here
Anonymous blogger “Deep Climate” weighs in with what he/she calls a “deeply flawed study” here
After a week of being “preoccupied” Real Climate finally breaks radio silence here. It appears to be a prelude to a dismissal with a “wave of the hand”
Supplementary Info now available: All data and code used in this paper are available at the Annals of Applied Statistics supplementary materials website:
http://www.imstat.org/aoas/supplements/default.htm
=========================================
Sticky Wicket – phrase, meaning: “A difficult situation”.
Oh, my. There is a new and important study on temperature proxy reconstructions (McShane and Wyner 2010) submitted into the Annals of Applied Statistics and is listed to be published in the next issue. According to Steve McIntyre, this is one of the “top statistical journals”. This paper is a direct and serious rebuttal to the proxy reconstructions of Mann. It seems watertight on the surface, because instead of trying to attack the proxy data quality issues, they assumed the proxy data was accurate for their purpose, then created a bayesian backcast method. Then, using the proxy data, they demonstrate it fails to reproduce the sharp 20th century uptick.
Now, there’s a new look to the familiar “hockey stick”.
Before:
After:
Not only are the results stunning, but the paper is highly readable, written in a sensible style that most laymen can absorb, even if they don’t understand some of the finer points of bayesian and loess filters, or principal components. Not only that, this paper is a confirmation of McIntyre and McKitrick’s work, with a strong nod to Wegman. I highly recommend reading this and distributing this story widely.
Here’s the submitted paper:
(PDF, 2.5 MB. Backup download available here: McShane and Wyner 2010 )
It states in its abstract:
We find that the proxies do not predict temperature significantly better than random series generated independently of temperature. Furthermore, various model specifications that perform similarly at predicting temperature produce extremely different historical backcasts. Finally, the proxies seem unable to forecast the high levels of and sharp run-up in temperature in the 1990s either in-sample or from contiguous holdout blocks, thus casting doubt on their ability to predict such phenomena if in fact they occurred several hundred years ago.
Here are some excerpts from the paper (emphasis in paragraphs mine):
This one shows that M&M hit the mark, because it is independent validation:
In other words, our model performs better when using highly autocorrelated
noise rather than proxies to ”predict” temperature. The real proxies are less predictive than our ”fake” data. While the Lasso generated reconstructions using the proxies are highly statistically significant compared to simple null models, they do not achieve statistical significance against sophisticated null models.
We are not the first to observe this effect. It was shown, in McIntyre
and McKitrick (2005a,c), that random sequences with complex local dependence
structures can predict temperatures. Their approach has been
roundly dismissed in the climate science literature:
To generate ”random” noise series, MM05c apply the full autoregressive structure of the real world proxy series. In this way, they in fact train their stochastic engine with significant (if not dominant) low frequency climate signal rather than purely non-climatic noise and its persistence. [Emphasis in original]
Ammann and Wahl (2007)
…
On the power of the proxy data to actually detect climate change:
This is disturbing: if a model cannot predict the occurrence of a sharp run-up in an out-of-sample block which is contiguous with the insample training set, then it seems highly unlikely that it has power to detect such levels or run-ups in the more distant past. It is even more discouraging when one recalls Figure 15: the model cannot capture the sharp run-up even in-sample. In sum, these results suggest that the ninety-three sequences that comprise the 1,000 year old proxy record simply lack power to detect a sharp increase in temperature. See Footnote 12
Footnote 12:
On the other hand, perhaps our model is unable to detect the high level of and sharp run-up in recent temperatures because anthropogenic factors have, for example, caused a regime change in the relation between temperatures and proxies. While this is certainly a consistent line of reasoning, it is also fraught with peril for, once one admits the possibility of regime changes in the instrumental period, it raises the question of whether such changes exist elsewhere over the past 1,000 years. Furthermore, it implies that up to half of the already short instrumental record is corrupted by anthropogenic factors, thus undermining paleoclimatology as a statistical enterprise.
…
We plot the in-sample portion of this backcast (1850-1998 AD) in Figure 15. Not surprisingly, the model tracks CRU reasonably well because it is in-sample. However, despite the fact that the backcast is both in-sample and initialized with the high true temperatures from 1999 AD and 2000 AD, it still cannot capture either the high level of or the sharp run-up in temperatures of the 1990s. It is substantially biased low. That the model cannot capture run-up even in-sample does not portend well for its ability
to capture similar levels and run-ups if they exist out-of-sample.
…
Conclusion.
Research on multi-proxy temperature reconstructions of the earth’s temperature is now entering its second decade. While the literature is large, there has been very little collaboration with universitylevel, professional statisticians (Wegman et al., 2006; Wegman, 2006). Our paper is an effort to apply some modern statistical methods to these problems. While our results agree with the climate scientists findings in some
respects, our methods of estimating model uncertainty and accuracy are in sharp disagreement.
On the one hand, we conclude unequivocally that the evidence for a ”long-handled” hockey stick (where the shaft of the hockey stick extends to the year 1000 AD) is lacking in the data. The fundamental problem is that there is a limited amount of proxy data which dates back to 1000 AD; what is available is weakly predictive of global annual temperature. Our backcasting methods, which track quite closely the methods applied most recently in Mann (2008) to the same data, are unable to catch the sharp run up in temperatures recorded in the 1990s, even in-sample.
As can be seen in Figure 15, our estimate of the run up in temperature in the 1990s has
a much smaller slope than the actual temperature series. Furthermore, the lower frame of Figure 18 clearly reveals that the proxy model is not at all able to track the high gradient segment. Consequently, the long flat handle of the hockey stick is best understood to be a feature of regression and less a reflection of our knowledge of the truth. Nevertheless, the temperatures of the last few decades have been relatively warm compared to many of the thousand year temperature curves sampled from the posterior distribution of our model.
Our main contribution is our efforts to seriously grapple with the uncertainty involved in paleoclimatological reconstructions. Regression of high dimensional time series is always a complex problem with many traps. In our case, the particular challenges include (i) a short sequence of training data, (ii) more predictors than observations, (iii) a very weak signal, and (iv) response and predictor variables which are both strongly autocorrelated.
The final point is particularly troublesome: since the data is not easily modeled by a simple autoregressive process it follows that the number of truly independent observations (i.e., the effective sample size) may be just too small for accurate reconstruction.
Climate scientists have greatly underestimated the uncertainty of proxy based reconstructions and hence have been overconfident in their models. We have shown that time dependence in the temperature series is sufficiently strong to permit complex sequences of random numbers to forecast out-of-sample reasonably well fairly frequently (see, for example, Figure 9). Furthermore, even proxy based models with approximately the same amount of reconstructive skill (Figures 11,12, and 13), produce strikingly dissimilar historical backcasts: some of these look like hockey sticks but most do not (Figure 14).
Natural climate variability is not well understood and is probably quite large. It is not clear that the proxies currently used to predict temperature are even predictive of it at the scale of several decades let alone over many centuries. Nonetheless, paleoclimatoligical reconstructions constitute only one source of evidence in the AGW debate. Our work stands entirely on the shoulders of those environmental scientists who labored untold years to assemble the vast network of natural proxies. Although we assume the reliability of their data for our purposes here, there still remains a considerable number of outstanding questions that can only be answered with a free and open inquiry and a great deal of replication.
===============================================================
Commenters on WUWT report that Tamino and Romm are deleting comments even mentioning this paper on their blog comment forum. Their refusal to even acknowledge it tells you it has squarely hit the target, and the fat lady has sung – loudly.
(h/t to WUWT reader “thechuckr”)
I’ve really enjoyed the diverse comments on this issue, as part of questioning and checking I’ve also visited other sites. What has amazed me is the fact that not all the other sites (particularly RC) seem to discuss the other opinion. You are hard pressed to even find the link to this breaking news. Surely the opinion around the world must be changing with the majority of people now, Gallup polls indicate more Australians are not taken in by Mannmade Global Warming, the UK are sick of the wind farms that do not work and get shut down on windy days, even located in the wrong place. Australians do not want a great big tax on everything to finance China as a developing nation. The farmers in Australia are supposed to grow food to feed the nation and export to the world, in reality the Greens are trying to cut production and lock up the land. Even Kevin Rudd had a go at the farmers by locking up the trees on the farmers land in the name of Kyoto.
Here are a few interesting facta re Australia and it’s CO2 output and government promises:
World Annual CO2 emissions (in thousands of metric tons) is 29,321,302. (Wikepedia)
Australia is ranked 16th in the world. (Wikepedia)
We produce 374,045.00 tonnes, 1.28% of World production
18702.25 tonnes = the 5% reduction of Australia output promised by politicians.
355342.75 = new level (Simple subtraction)
1.2188928 = new % (1.22 approx)
1.28 – 1.22 = 0.06% of world output.
We are risking the collapse of our economy and mining industry for 0.06% saving, IF we stopped all output and shut down Australia we would still have minimum impact.
The whole scenario by Labor is a tax grab and a scam.
If we bring in an ETS or Carbon scheme all the benefits will go to China and India. We will become a minor player in world economy. If you want to go backwards vote Green. Green means Stop.
Sooo. What happens to parlor talk when the entire global warming thing becomes a passe’ non-topic. Whatever will we talk about then? What about the politicians, the poor dears – what will they use to beat their opponents with when the issue is no-longer an issue? Oh, my.
Poptech says: (August 16, 2010 at 1:38 pm)
“Author Bios:…”
Very impressive but sadly they are not “experts” in climatology so therefore their opinion doesn’t count, only if sanctioned by “the Team”.
@duckster:
Micheal said: In essence you are correct but the English language is the problem, I think
2. The authors accept the data used by Mann et al. as it stands. Questioning its veracity is beyond the scope of the paper. It is not addressing scientific issues, but is solely an investigation of the data by professional statisticians, who have often not been explicitly involved in past statistical analyses. This point has also been made, for example, in the conclusions of the Oxburgh “Climategate” enquiry.
This was not an investigation of the data, as I read it but of the statistical method(s). In effect, they concluded that their non-novel statistical analysis indicated that there was too much uncertainty in the results to make the conclusions offered by Mann et al. In other words, both warming and cooling were within the range of uncertainty of their analysis using Mann’s data. There is no conclusion to be found about the data. You must also read this paper with tongue in cheek. Ie look for the hidden sarcasm.
But essentially your on the nail.
Curiousgeorge says:
Sooo. What happens to parlor talk when the entire global warming thing becomes a passe’ non-topic.
Global warming is so last year!
By latching on to apocalyptic claptrap like AGW, the policies our leaders come up with in respect to the issue are never going to work, and what little good the policies actually do will be at a far higher price than the actual cost should be.
James Sexton says:
August 16, 2010 at 12:18 pm
”
Agreed. I’m wondering if what we are seeing here isn’t something worth studying itself? It seems an overwhelming majority of the alarmists seem only to look at the pretty pictures and assume a story from ther… So, my question is this;
Is this why there are so many CAGW believers out there? Do they simply look at the pictures and let someone else tell them what it means or is it left to them to make wild assumptions to the meaning of the pretty pictures without actually reading an explanation?…
… Dear God! Has it come to this? Has this world, as the majority of the population, capitulated its God given right to contemplate and even think for itself? I guess I now know why when I make a reference to 1984 I get very few responses from the alarmists. There aren’t any pictures to assume a story. I’m simply flabbergasted at the either willful refusal to read or the inability to accomplish the reading.
________________________________________________________________
It is the inability to read and to reason. That is the objective of John Dewey’s “Modern Education” to make people co-dependent (team players) not IN-dependent.
“On average, American high school graduates are two years behind much of the world, including some countries that could be called “third world.” Prior to the 1930’s, students were given an exam to graduate from the eighth grade, which typical high school graduates couldn’t pass today, because it’s too difficult. One modern social commentator educated during this era, has remarked that “even the ‘F’ students could read.” The kind of things that literate people need to know hasn’t really changed enough (at a primary and secondary level anyway) that this phenomena is justified. The vast increases in the relative number of “leaning disabled” students, and the resulting loss of human potential, is just sickening. The bulk of the responsibility for these massive, tragic declines in education can be laid at the feet of the leaders of the Humanist education community. Their obsessive meddling with the basic process and pedagogy of education, conducted in their zeal to make education more philosophically (e.g. “modern” Humanist) and politically correct, is the primary cause of the decline.” http://ldolphin.org/humanism.html
“…..Dewey’s philosophy had evolved from Hegelian idealism to socialist materialism, and the purpose of the school was to show how education could be changed to produce little socialists and collectivists instead of little capitalists and individualists. It was expected that these little socialists, when they became voting adults, would dutifully change the American economic system into a socialist one.
In order to do so he analyzed the traditional curriculum that sustained the capitalist, individualistic system and found what he believed was the sustaining linchpin — that is, the key element that held the entire system together: high literacy. To Dewey, the greatest obstacle to socialism was the private mind that seeks knowledge in order to exercise its own private judgment and intellectual authority. High literacy gave the individual the means to seek knowledge independently. It gave individuals the means to stand on their own two feet and think for themselves. This was detrimental to the “social spirit” needed to bring about a collectivist society. …” http://www.ordination.org/dumbing_down.htm
Note: This is an older paper. Pamela Grey has said they have finally moved away from the reading method discussed in the paper. Unfortunately we have generations of voting adults who were effected and the Humanist philosophy and “Political Correctness” is still a major force in today’s education.
evanmjones says:
August 18, 2010 at 1:41 am
Evan, spot on as always. Climate science has very little to do with science at the conclusion level. Yes to science for gathering and understanding the data, it’s significance, it’s problems, etc but no to science for the analysis. It is entirely about stats. That’s why Steve Mc’s work has been so precious. It’s why the dogs of climate science were never able to dismiss his work. It’s why these websites are so important.
NeilT
After reading your first comment, I thought you had forgotten to include the
/sarc off
Your second comment shows how sociology majors look at science and scientists.
The old saying stands: Sufficiently high technology (no great height in your case) is indistinguishable from magic.
Hal
nofreewind says: August 17, 2010 at 6:10 pm
But have the 20th Century even warmed since 1940?, except for the step up with the 98 El Nino. Why not look at the data. The thermometer record from 1940 to 1979 shows NO WARMING, both of them, the satellite record from 1979 to 1997 show NO WARMING, both of them.
I have looked at the temperature series this way previously. The thermometer record pre-1979 is probably pretty good, some UHI. The introduction of the MMTS and moving recording stations to airports, plus adjusting temperatures up for UHI certainly invalidates the ground readings post-1979. While some might complain this is cherry-picking, it may be true but only to include the best data.
duckster says: August 18, 2010 at 3:46 am
Good question. What’s the answer? Is there a 900 year cycle, or are people confusing correlation with causation, as has happened with CO2 and temperature.
That’s why you should ask a statistician. Is this signal, or is this noise? How certain am I that the signal is really there, or it’s statistically significant?
Indeed, and you might even see it in some of the long timescale proxies. But you’d still have to explain it. Climate change isn’t anything unusual. We’ve just been oversold on the idea that this one is somehow different, and that may not be correct.
@Henry Pool
“You have not proven that CO2 is a greenhouse gas, i.e. that its cooling properties are smaller than its warming properties.”
Evidently not to your satisfaction. The radiation energy available in CO2 absorption bands are overwhelmingly in frequencies that a 10,000 degree Fahrenheit source (i.e. the sun) emits very little of but are rather in the bands that a 60F source (the ocean) emits copiously.
The overall effect is the sun heats the ocean, the ocean heats the atmosphere, the cold void of outer space cools the atmosphere.
CO2 plays a small role as an insulator slowing down the transport of energy from the ocean to outer space. Water vapor is the main actor among the insulating gases.
“Unless there is something wrong with the definition of a GHG. I think they also call ozone a GHG.”
Ozone is a different story as it has a strong absorption band in ultraviolet where the sun emits strongly as well as in infrared where the ocean emits strongly.
“But if you look carefully at the incoming radiation, then ozone on its own cuts away almost 15-20% of the sun’s radiation. That what ozone cuts away from earth’s radiation compares to not much with that 15-20%. So I am sure ozone is cooling more than it is warming. But they still call it a CHG?”
It does in fact insulate the earth from ultraviolet energy which the sun emits copiously but it also absorbs infrared which the earth emits copiously. The difference is a few percent in favor of infrared absorption.
Keep in mind water vapor is the mother of all greenhouse gases and its infrared absorption bands overlap those of other greenhouse gases to a large extent so where there is significant water vapor (just about everywhere in the troposphere) the other gases play a very small role.
I’m sure you knew all that but choose to disbelieve parts of it and nothing I can say is going to change that.
Henry Pool
…..”CO2 also absorbs strongly at between 4-5 where both earth and sun radiate. “….
I agree this wavelength is almost ignored by climate scientists.
Yet is should be quite the opposite as its the one wavelength that does not overlap with water vapour and could identify the extent of any CO2 effect.
It seems obvious that the team is really frightened about this one and are tryin to push the line that it confirms Mann et al what a joke! Deltoid represents what Australian education and science has become… 3rd world level…. period.
NeilT says:
August 17, 2010 at 11:17 pm
The statisticians say that in the last 1,000 years the data is patchy and causes huge error bars. However they say that the reconstructions track extremely well with 120 out of the 150 years of the instrument record. Then they go on to say and SHOW that the reconstructions can’t predict the warming in the last 30 years.
============================================================
“”“[T]he proxy record has some ability to predict the final thirty-year block, where temperatures have increased most significantly, better than chance would suggest.”
============================================================
Neil, that’s hogwash and here’s why.
They used Mann’s numbers and statistics to recreate the entire thing.
Their process did not change for the last thirty years, only Mann’s numbers changed.
The exact same process – statistics – gives foggy results in the beginning, and then more accurate results the last thirty years.
That has nothing to do with physics, statistics, or who did it.
That only points out that Mann changed his numbers the final thirty years. The process did not change in the final thirty year block, only the numbers they plugged in.
@Atomic Hairdryer and Duckster
There are cycles as short as daily to at least as long as one hundred thousand years. There are many cycles of intermediate length in between those two. Where or not the data exists to identify them with some degree of confidence is the crux.
Science is in the business of collecting the data. Math is in the business of correlating the data. Then science is back in the business of explaining the correlations in terms of causation.
What we have here in Mann’s case is he’s a go-to guy for data collection. A mathmetician specializing in statistical probability is the go-to guy for correlating the data. A physicist is often the go-to guy in coming up with explanations of causation.
Michael Larkin says:
August 18, 2010 at 1:46 am
That’s pretty much the way I read it, too.
However, stephen richards says: August 18, 2010 at 5:21 am nails it! “You must also read this paper with tongue in cheek. Ie look for the hidden sarcasm.” Throughout the paper, it seems to be a continuous stream of what I referred to as (b)slaps. Simplify the statements and re-word them into familiar language. For instance, the final statement of the conclusions, “Our work stands entirely on the shoulders of those environmental scientists who labored untold years to assemble the vast network of natural proxies. Although we assume the reliability of their data for our purposes here, there still remains a considerable number of outstanding questions that can only be answered with a free and open inquiry and a great deal of replication.”
While this isn’t the most harmful of (b)slaps, it is quite humorous to me. The first sentence acknowledges the work the scientists have done in collecting the data throughout the years. Given the use of the data, I can’t help but recall what Dr. Phil had to say when he was given some FOI requests. “Why should I when………” And so M&W did exactly that. Only to a different player on the “team”. The second sentence is in two parts. The first one reiterates the “assumption” of the reliability of the data. But with the caveat “for our purposes here.”, I infer that caveat means quite the opposite because they immediately follow with the words, “considerable number of outstanding questions”. And the final part of the final sentence in the conclusions section. “can only be answered with a free and open inquiry and a great deal of replication.” Given the history of Mann and his unwillingness to share methods and the like and given replication is a huge missing component of current climate science, I can’t see how any CAGW “scientist” could read that with out having a stroke! They don’t do replication, they don’t share and they believe their data is “robust”. The last paragraph addressed all 3 of those points in carefully crafted words. Just for fun, go up one paragraph and do the same exercise I just described. It’s really quite funny.
“Natural climate variability is not well understood and is probably quite
large. It is not clear that the proxies currently used to predict temperature
are even predictive of it at the scale of several decades let alone over many
centuries. Nonetheless, paleoclimatoligical reconstructions constitute only
one source of evidence in the AGW debate.”
Henry@DaveSpringer&Bryan
dave says:
It does in fact insulate the earth from ultraviolet energy which the sun emits copiously but it also absorbs infrared which the earth emits copiously. The difference is a few percent in favor of infrared absorption.
Richard.
You restate:
As I have already agreed with this (for the sake of argument), I don’t understand why you reassert it.
The composite of data records (thermometer readings) for the 20th century show warming. There is much better coverage and continuity in these records (though not perfect) than in proxy indicators stretching back over the last millennium.
They do not. Some show a cool period for that time frame, and warming at different times. Here are some examples.
Buddha Cave, Qin Ling, China (top right reconstruction) shows the peak of medieval warming at 1400 AD. That peak is cooler than the current warm period, and the period 750 to 1250 AD is much cooler.
New Zealand Stalagmite (bottom right) has MWP peak at about 1400, and the classic MWP period much cooler than the latter part of the 20th century.
Northern Icelandic Ice shelf records show a warm spike at 750 AD, immediately followed by 3 centuries of temperatures much cooler than today’s.
Teletskoye Lake, Siberia has two warming peaks at 1400 and 1450, and significantly cooler temps prior to 1250 (although the record does not extend before 1200)
Southampton Island, Canada, shows a peak at 1300, and strikingly cool temps centred on 1150.
A number of the records do match the curve you describe. Others show the MWP being relatively cool compared to recent temps. And that’s just the 40-odd proxy records on the interactive map. There are hundreds more.
Therefore, the putative MWP is not spatially and temporally coherent on a global. Composite studies indicate that temperatures were generally warm in the period 750 – 1250 AD, but this is by no means true for all proxies.
You then refer me back to the interactive map.
So these are reliable – even though some of them are used by MBH (and Gavin Schmidt). This brings us back to the question of what the result is when these records are combined.
You go on:
You previously stated
This comment was the first time the alleged 900-year cycle and MBH were brought together. No mentio0n of MWP or LIA. In fact, I introduced those phenomena on this particular topic in my following reply to you.
The graphical representations show wide error bars. Both MBH and the IPCC maintain there was a MWP of similar warmth to the mean of the 20th century, and that the LIA was significantly cooler. If you wish to discuss the graphs, then we are moving into a political discussion, in which I am not interested. If you wish to talk about the scientific findings of MBH (and/or IPCC), then we must look beyond the graphs at the text of the documents. They bear out what I am saying. The MWP and LIA are real phenomena, and their amplitude is estimated in MBH 99 (and 98).
————————————————————————————–
In the first decade of the previous two cooling phases (1880 – 1890, and 1940 – 1950), the temperature trend was downwards. This is not the case for the alleged cooling phase 2000 to present.
If you contend that a few more years will make a cooling trend apparent, could you give an estimate (nominate a year in the future) when you think this will be demonstrated. When might be the earliest date we could expect a downward trend from 2000 to emerge?
Ulf says:
August 18, 2010 at 1:01 am
Strictly speaking, any value within the error bars could be the “correct” one.
MW10 seems to be mainly about assessing the uncertainties of the reconstructions. This is where they claim that “Climate scientists have greatly underestimated the uncertainty”.
========================================================
Exactly, you can run a straight horizontal line, never get out of “error”, and show no warming or cooling at all.
Duckster,
Go back and read my presentation, http://www.kidswincom.net/climate.pdf, with an open mind. In analyzing the the ice core isotope depletion data with several different statistical techniques, I was able to identify 13, statistically significant, naturally occuring cyles. The shortest significant cycle from the combined data was around twenty years and the longest was around 100,000 years. Plotting the best fit of all these natural cycles clearly shows both the MWP and LIA, as well as the Roman warm period.
If you question my ability to use statistics correctly, Google “Fred H. Haynie”+ statistics.
@Brian and Henry
http://www.te-software.co.nz/blog/auer_files/image001.gif
The sun and the earth both emit very little energy at 4-5 microns so it has very little impact one way or another.
Henry@DaveSpringer&Bryan
Dave says:
It (ozone) does in fact insulate the earth from ultraviolet energy which the sun emits copiously but it also absorbs infrared which the earth emits copiously. The difference is a few percent in favor of infrared absorption.”
Henry says:
You have to be kidding me? Where do you get this 6% from? In what Si units?
From the graph you quoted ozone makes a little dent in earth’s radiation (blue) at 13 um, the area of which is much, much smaller than that whole white area caused by ozone in the red zone (left).
The point is: there are no results of research that will give me an accurate balance sheet of the cooling and warming of CHG’s in W/m3 %GHG/m2/24 hours.
So, unless you have those results, you don’t know if CO2 is greenhouse gas.
DaveSpringer says:
The sun and the earth both emit very little energy at 4-5 microns so it has very little impact one way or another.
Henry says:
So how come here in Africa you cannot stand in the sun for longer than 10 minutes because of the IR heat on your skin?
It may be very little to you, but how many Watts/m2 does it cause?