Heliogenic Climate Change

“1.  INTRODUCTION

Global warming scenarios from CO2 increases are envisioned to bring about rainfall enhancement and resulting upper tropospheric water vapor rise. This initial water vapor enhancement has been hypothesized and programmed in climate models to develop yet additional rainfall and water vapor increase. This causes an extra blockage of IR energy to space (a positive feedback warming mechanism). This additional rainfall and IR blockage is modeled to be approximately twice as large as the additional rainfall needed to balance the increased CO2 by itself. The reality of this additional warming and extra IR blockage has been questioned by many of us. This study analyzes a wide variety of infrared (IR) radiation differences which are associated with rainfall differences on different space and time scales. Our goal is to determine the extent to which the positive rainfall feedbacks as are included in the climate model simulations are realistic.  …

This analysis shows they are not realistic.  …

2.  FINDINGS

a)
The albedo increase occurring over the top of strong precipitation and cloudy regions rises at a greater rate than does the rate of decrease of IR within these rainy and cloudy areas. Rainy and cloudy areas are local places of enhanced net radiation to space (Tables 1 and 2 and in idealized form in Figure 3). We have many other areas of rain differences which give similar results. In almost all rain and cloud areas we find that albedo energy flux rises at a greater rate than IR energy flux is reduced.  …

3.  IMPLICATIONS OF THESE OBSERVATIONS

The above measurements are at odds with the Global Climate Model (GCM) simulations of precipitation increase associated with rising CO2 amounts. Models show large tropical upper tropospheric temperature and water vapor increases to be associated with increased rates of precipitation (due to CO2 increases) that are similar to increased rates of precipitation that this study measures. We do not observe such upper tropospheric temperature and moisture increases for rainfall enhancements as do the modelers.  …

The climate modelers have assumed that as CO2 increases it will cause a progressive blockage of IR energy to space and, in addition, a further blockage of IR energy to space will occur from the original increase in upper-level water vapor. Increased IR blockage brings about a gradual increase in global temperature.  …

Our observations do not agree with these GCM scenarios. Our observations indicate that tropical RH [relative humidity] and moisture (q) rather than rising with enhanced precipitation do the opposite and actually go down as precipitation rates increase.  …

We find that there is not a positive water vapor feedback as the modelers have assumed. In fact we see the opposite. As rainfall increases upper-level water vapor contents are weakly reduced.  …

8. CONCLUSION

We find that as rainfall increases that there is not a reduction of global net radiation to space as most of the climate models have assumed. There is a weak enhancement of radiation to space with increased rainfall. We find no positive water vapor feedback.  …

A reduction of upper level RH of about 4 percent to go along with a lowering of the emission level of 7 mb would allow a doubling of CO2 to proceed with no warming (Figure 20). We estimate the extra precipitation from a doubling of CO2 to cause a negative (not positive) temperature feedback of about minus 0.6oC.”  “THE ASSOCIATION OF OUTGOING RADIATION WITH VARIATIONS OF PRECIPITATION – IMPLICATIONS FOR GLOBAL WARMING“  h/t Climate Realists

“Abstract: To estimate climate sensitivity from observations, Lindzen and Choi [2009] used the deseasonalized fluctuations in sea surface temperatures (SSTs) and the concurrent responses in the top-of-atmosphere outgoing radiation from the ERBE satellite instrument. Distinct periods of warming and cooling in the SST were used to evaluate feedbacks. This work was subject to significant criticism by Trenberth et al. [2009], much of which was appropriate. The present paper is an expansion of the earlier paper in which the various criticisms are addressed and corrected. In this paper we supplement the ERBE data for 1985-1999 with data from CERES for 2000-2008. Our present analysis accounts for the 36 day precession period for the ERBE satellite in a more appropriate manner than in the earlier paper which simply used what may have been undue smoothing. The present analysis also distinguishes noise in the outgoing radiation as well as radiation changes that are forcing SST changes from those radiation changes that constitute feedbacks to changes in SST. Finally, a more reasonable approach to the zero-feedback flux is taken here. We argue that feedbacks are largely concentrated in the tropics and extend the effect of these feedbacks to the global climate. We again find that the outgoing radiation resulting from SST fluctuations exceeds the zero-feedback fluxes thus implying negative feedback. In contrast to this, the calculated outgoing radiation fluxes from 11 atmospheric GCMs [global climate models] forced by the observed SST are less than the zero-feedback fluxes consistent with the positive feedbacks that characterize these models. The observational analysis implies that the models are exaggerating climate sensitivity.”  “On the observational determination of climate sensitivity and its implications“  h/t The Hockey Schtick

Posts on Lindzen and Choi 2009 here, here, and here.

“In my articles to date I have been unwilling to claim anything as grand as the creation of a new model of climate because until now I was unable to propose any solar mechanism that could result directly in global albedo changes without some other forcing agent or that could account for a direct solar cause of discontinuities in the temperature profile along the horizontal line of the oceanic thermohaline circulation.  I have now realised that the global albedo changes necessary and the changes in solar energy input to the oceans can be explained by the latitudinal shifts (beyond normal seasonal variation) of all the air circulation systems and in particular the net latitudinal positions of the three main cloud bands namely the two generated by the mid latitude jet streams plus the Inter Tropical Convergence Zone (ITCZ).

The secret lies in the declining angle of incidence of solar energy input from equator to poles.

It is apparent that the same size and density of cloud mass moved, say, 1000 miles nearer to the equator will have the following effects:

i) It will receive more intense irradiation from the sun and so will reflect more energy to space.

ii) It will reduce the amount of energy reaching the surface compared to what it would have let in if situated more poleward.

iii) In the northern hemisphere due to the current land/sea distribution the more equatorward the cloud moves the more ocean surface it will cover thus reducing total solar input to the oceans and reducing the rate of accretion to ocean energy content.

iv) It will produce cooling rains over a larger area of ocean surface.

As a rule the ITCZ is usually situated north of the equator because most ocean is in the southern hemisphere and it is ocean temperatures that dictate it’s position by governing the rate of energy transfer from oceans to air. Thus if the two mid latitude jets move equatorward at the same time as the ITCZ moves closer to the equator the combined effect on global albedo and the amount of solar energy able to penetrate the oceans will be substantial and would dwarf the other proposed effects on albedo from changes in cosmic ray intensity generating changes in cloud totals as per Svensmark and from suggested changes caused in upper cloud quantities by changes in atmospheric chemistry involving ozone which various other climate sceptics propose.

Thus the following NCM will incorporate my above described positional cause of changes in albedo and rates of energy input to the oceans rather than any of the other proposals. That then leads to a rather neat solution to the other theories’ problems with the timing of the various cycles as becomes clear below.”

Read more here:  “A new and effective climate model“

“New NASA measurements of the Atlantic Meridional Overturning Circulation, part of the global ocean conveyor belt that helps regulate climate around the North Atlantic, show no significant slowing over the past 15 years. The data suggest the circulation may have even sped up slightly in the recent past.

The findings are the result of a new monitoring technique, developed by oceanographer Josh Willis of NASA’s Jet Propulsion Laboratory in Pasadena, Calif., using measurements from ocean-observing satellites and profiling floats. The findings are reported in the March 25 issue of Geophysical Research Letters.

The Atlantic overturning circulation is a system of currents, including the Gulf Stream, that bring warm surface waters from the tropics northward into the North Atlantic. There, in the seas surrounding Greenland, the water cools, sinks to great depths and changes direction. What was once warm surface water heading north turns into cold deep water going south. This overturning is one part of the vast conveyor belt of ocean currents that move heat around the globe.  …

Willis found evidence that the circulation had sped up about 20 percent from 1993 to 2009. This is the longest direct record of variability in the Atlantic overturning to date and the only one at high latitudes.

The latest climate models predict the overturning circulation will slow down as greenhouse gases warm the planet and melting ice adds freshwater to the ocean.”  “NASA Study Finds Atlantic ‘Conveyor Belt’ Not Slowing“

“Abstract: The National Centers for Environmental Prediction (NCEP) reanalysis data on tropospheric humidity are examined for the period 1973 to 2007. It is accepted that radiosonde-derived humidity data must be treated with great caution, particularly at altitudes above the 500 hPa pressure level. With that caveat, the face-value 35-year trend in zonal-average annual-average specific humidity q is significantly negative at all altitudes above 850 hPa (roughly the top of the convective boundary layer) in the tropics and southern midlatitudes and at altitudes above 600 hPa in the northern midlatitudes. It is significantly positive below 850 hPa in all three zones, as might be expected in a mixed layer with rising temperatures over a moist surface. The results are qualitatively consistent with trends in NCEP atmospheric temperatures (which must also be treated with great caution) that show an increase in the stability of the convective boundary layer as the global temperature has risen over the period. The upper-level negative trends in q are inconsistent with climate-model calculations and are largely (but not completely) inconsistent with satellite data. Water vapor feedback in climate models is positive mainly because of their roughly constant relative humidity (i.e., increasing q) in the mid-to-upper troposphere as the planet warms. Negative trends in q as found in the NCEP data would imply that long-term water vapor feedback is negative—that it would reduce rather than amplify the response of the climate system to external forcing such as that from increasing atmospheric CO2. In this context, it is important to establish what (if any) aspects of the observed trends survive detailed examination of the impact of past changes of radiosonde instrumentation and protocol within the various international networks.”  “Trends in middle- and upper-level tropospheric humidity from NCEP reanalysis data“

“Contrary to scientists’ predictions that, as the Earth warms, the movement of trees into the Arctic will have only a local warming effect, University of California, Berkeley, scientists modeling this scenario have found that replacing tundra with trees will melt sea ice and greatly enhance warming over the entire Arctic region.

Because trees are darker than the bare tundra, scientists previously have suggested that the northward expansion of trees might result in more absorption of sunlight and a consequent local warming.

But UC Berkeley graduate student Abigail L. Swann, along with Inez Fung, professor of earth and planetary science and of environmental science, policy and management, doubted this local scenario because, while broad-leaved trees are dark, they also transpire a lot of water, and water vapor is a greenhouse gas that is well-mixed throughout the Arctic.

Taking account of this in a standard model of global warming, the researchers discovered that, while broad-leaved trees do absorb some additional sunlight, the water vapor they pump into the atmosphere causes a more widespread warming.”  “Trees invading warming Arctic will cause warming over entire region, study shows“

“[T]he Bray and von Storch survey also reveals that very few of [the 373 scientists who work for climate research institutes] trust climate models — which form the basis of claims that human activity could have a dangerous effect on the global climate. Fewer than 3 or 4 percent said they “strongly agree” that computer models produce reliable predictions of future temperatures, precipitation, or other weather events. More scientists rated climate models “very poor” than “very good” on a long list of important matters, including the ability to model temperatures, precipitation, sea level, and extreme weather events.  …

Computer models are practically the only “proof” that global warming alarmists have to support their theory and forecasts. How can scientists know that global warming is man-made and will be a crisis, while at the same time express deep skepticism towards the computer models that might support such beliefs?

The answer is that they don’t actually “know” global warming is man-made or will be a disaster; they “believe” this to be true.”  “Understanding the Global Warming Delusion“

“Monkey species will become ‘increasingly at risk of extinction’ because of global warming, according to new research, published this week. It reveals that populations of monkeys and apes in Africa that depend largely on a diet of leaves may be wiped out by a rise in annual temperatures of two degrees Celsius. …

The researchers used climate models coupled with an analysis of quantitative data on the behaviour, diet and group size of different primate species across the world.” “African Leaf-Eating Primates ‘Likely to Be Wiped Out’ by Climate Change“

Primates evolved and thrived in Africa during many, many periods of much warmer temperatures than today. What happened to “peer review” with this “research” paper? Could it be, as Cliff Mass says, “Poor papers with significant technical problems, but reflecting the “official” line, get published easily, while papers indicating the global warming is weaker or delayed, go through hurdle after hurdle”?
-

My editorial comments are bracketed in red:

“Researchers studying a period of high carbon dioxide levels and warm climate several million years ago have concluded that slow changes such as melting ice sheets amplified the initial warming caused by greenhouse gases. [rise in CO2 occurs about 800 years after initial natural warming according to ice cores]

The study, published in the journal Nature Geoscience, found that a relatively small rise in atmospheric carbon dioxide levels was associated with [ditto] substantial global warming about 4.5 million years ago during the early Pliocene.

Coauthor Christina Ravelo, professor of ocean sciences at the University of California, Santa Cruz, said the study indicates that the sensitivity of Earth’s temperature to increases in carbon dioxide in the atmosphere is greater than has been expected on the basis of [GIGO] climate models that only include rapid responses.” “Global warming likely to be amplified by slow changes to Earth systems“

“”[NASA's] AIRS [satellite] temperature and water vapor observations have corroborated climate model predictions that the warming of our climate produced as carbon dioxide levels rise will be greatly exacerbated — in fact, more than doubled — by water vapor,” said Andrew Dessler, a climate scientist at Texas A&M University, College Station, Texas.” “NASA Outlines Recent Breakthroughs in Greenhouse Gas Research“

“We find that on a small space scale where rainfall is occurring OLR [outgoing longwave radiation] is greatly suppressed. But on the larger regional to global scales, OLR rises with increasing precipitation. This is due to increased return flow subsidence in the surrounding cloud free and partly cloudy areas. Globally, we are finding that net OLR increases with net increased amounts of global precipitation. This is the opposite of what most GCMs [general circulation models] have programmed into their models and, if I’m interpreting the new NASA announcement correctly, opposite to what they are currently reporting to the media.” “Is “several degrees” of warming “virtually certain” as NASA claims?“
-

“But most of the talks presented [at the AGU meeting] followed the recipe that has become all too common in recent years: analyze the output of climate models that predict substantial global warming, and simply assume the models are somewhere near correct.

There seems to be great reluctance to consider the possibility that these computerized prophets of doom, which have required so many scientists and so much money and so many years to develop, could be wrong. I come along with an extremely simple climate model that explains the behavior of the satellite data in details that are beyond even what has been done with the complex climate models…and then the more complex models are STILL believed because…well…they’re more complex.

Besides, since my simple model would predict very little manmade global warming, it must be wrong. After all, we know that manmade global warming is a huge problem. All of the experts agree on that. Just ask Al Gore and the mainstream news media.” “Little Feedback on Climate Feedbacks in the City by the Bay“

““The climate modelers see from satellite data that warm years have fewer clouds, then assume that the warmth caused the clouds to dissipate. If this is true, it would be positive feedback and could lead to strong global warming. This is the way their models are programmed to behave.

“My question to them was, ‘How do you know it wasn’t fewer clouds that caused the warm years, rather than the other way around?’ It turns out they didn’t know. They couldn’t answer that question.”

One problem is the simplicity of the climate models. Because cloud systems are so complex and so poorly understood, all of the climate models used by the United Nations’ Intergovernmental Panel on Climate Change use greatly simplified cloud parameters to represent clouds. But the calculations that set those parameters are based on assumed cause-and-effect relationships.

Those assumptions might be working in the wrong direction, Spencer said. “What we have found is that cloud cover variations causing temperature changes dominate the satellite record, and give the illusion of positive feedback.”

Using satellite observations interpreted with a simple model, Spencer’s data support negative feedback (or cooling) …” “Cloud Feedback Presentation for Fall 2009 AGU Meeting” Prior posts here, here, here, here, and here.
-

Kinda reminds you of Humphrey Bogart with the ball bearings in his hand in The Caine Mutiny:

“The e-mail archives stolen last month from the Climatic Research Unit at the University of East Anglia (UEA), UK, have been greeted by the climate-change-denialist fringe as a propaganda windfall. To these denialists, the scientists’ scathing remarks about certain controversial palaeoclimate reconstructions qualify as the proverbial ‘smoking gun’: proof that mainstream climate researchers have systematically conspired to suppress evidence contradicting their doctrine that humans are warming the globe.

This paranoid interpretation would be laughable were it not for the fact that obstructionist politicians in the US Senate will probably use it next year as an excuse to stiffen their opposition to the country’s much needed climate bill. Nothing in the e-mails undermines the scientific case that global warming is real — or that human activities are almost certainly the cause. …

Denialists often maintain that these changes are just a symptom of natural climate variability. But when climate modellers test this assertion by running their [absurd model] simulations with greenhouse gases such as carbon dioxide held fixed, the results bear little resemblance to the observed warming. …

A fair reading of the e-mails reveals nothing to support the denialists‘ conspiracy theories. …

If there are benefits to the e-mail theft, one is to highlight yet again the harassment that denialists inflict …

The e-mail theft also highlights how difficult it can be for climate researchers to follow the canons of scientific openness …

One e-mail talked of displaying the data using a ‘trick’ — slang for a clever (and legitimate) technique, but a word that denialists have used to accuse the researchers of fabricating their results. …

In the end, what the UEA e-mails really show is that scientists are human beings — and that unrelenting opposition to their work can goad them to the limits of tolerance, and tempt them to act in ways that undermine scientific values. … After all, the pressures the UEA e-mailers experienced may be nothing compared with what will emerge as the United States debates a climate bill next year, and denialists use every means at their disposal to undermine trust in scientists and science.” “Climatologists under pressure“

“Dozens of epoch-changing moments are preserved in the library of Britain’s Royal Society, an academy of scientists founded in 1660 to gather, discuss and spread scientific knowledge — a role it still fills today.

Its members, dedicated to discovery through observation and experiment, form a roll-call of scientific fame: Isaac Newton, Benjamin Franklin, Charles Darwin, Stephen Hawking. All contributed scientific papers that together recount what geneticist Alec Jeffreys –_ the father of DNA fingerprinting and a current member of the society — calls “this amazing journey over the past 350 years.” …

The society, which serves as Britain’s national science academy, lobbies the government _ climate change is a major current concern _ and promotes science education.” “Royal Society Celebrates 350 Years of Discovery“

How ironic that the Royal Society, once “dedicated to discovery through observation and experiment”, now is part of the AGW cabal, which is based only on a theory, not observation or experiment, which assumes a climate sensitivity an order of magnitude too large and a feedback of the wrong sign. This is from their official position on climate change:

“International scientific consensus agrees that increasing levels of man-made greenhouse gases are leading to global climate change.” “Climate change“

Once “dedicated to discovery through observation and experiment”, now dedicated to consensus. Newton would be appalled.
-

“A new paper that is soon to appear in the journal Geophysical Research Letters finds that across the U.S. daily record high temperatures are being set at about twice the frequency of daily record low temperatures and that this ratio—number of record highs to the number of record lows, has been growing larger over the past 50 years.

The popular press seems to be particularly taken with this finding, although headline proclamations fail to disclose important details of the actual findings reported by the National Center for Atmospheric Research’s (NCAR) Gerald Meehl and colleagues.

Although you can hardly blame the press, because the NCAR press release did much to lead them down this muddy path.

Meehl et al. find that the reason more daily maximum temperature records are being set than daily minimum temperatures records is because there are fewer than expected daily lows records being set, not because there are more daily high records than expected.

In other words, our days are not becoming extremely hotter, but our nights are becoming less extremely cold. This fact is buried in the press release and consequently in most of the coverage—likely, because this finding has pretty benign, if not beneficial, implications. …

[The process of urbanization] warm[s] nights more than days, … — something which has not been accounted for in the results of Meehl et al. (because it is virtually impossible to do so at a daily level), but something that is widely known to be occurring.

A report just published earlier this week estimates that urbanization and other land use changes are responsible for half of the observed temperature rise in recent decades in the U.S. This is similar to what Ross McKitrick and WCR editor Pat Michaels found for global land-based temperatures in a paper published two years ago. …

[W]hile the observations suggest that our nights are warming faster than our days, this is not so in the NCAR climate model which suggests that the days and nights are warming up at the same rate. Such a model error leads to the model grossly overestimating the frequency and intensity of future heat waves. …

Repeat after us—if the models can’t replicate reality (for the right reasons) they can’t reliably predict the future.

So, the bottom line here is this—climate change in the U.S. during the past 50 years has resulted in fewer extreme nighttime low temperatures, while the daily extreme high temperatures have been little affected. And, at least one leading climate model fails to correctly capture this behavior.

Ask yourself this, is this the impression that you got from the coverage of this in the popular press?” “U.S. record temperatures — a closer look“

“[T]he closure of thousands of rural stations and expansion of urban areas into previously rural or suburban areas [has created] enormous “heat sinks,” that prevent night time temperatures from dropping to the extent that they would in a nearby rural setting. Hence more stations reporting greater frequencies of maximum temperatures and fewer minimums.” “A critique of the October 2009 NCAR study regarding recording maximum to minimum ratios“
-

“New data show that the balance between the airborne and the absorbed fraction of carbon dioxide has stayed approximately constant since 1850, despite emissions of carbon dioxide having risen from about 2 billion tons a year in 1850 to 35 billion tons a year now.

This suggests that terrestrial ecosystems and the oceans have a much greater capacity to absorb CO₂ than had been previously expected.

The results run contrary to a significant body of recent research [climate models] which expects that the capacity of terrestrial ecosystems and the oceans to absorb CO₂ should start to diminish as CO₂ emissions increase, letting greenhouse gas levels skyrocket. Dr Wolfgang Knorr at the University of Bristol found that in fact the trend in the airborne fraction since 1850 has only been 0.7 ± 1.4% per decade, which is essentially zero.

The strength of the new study, published online in Geophysical Research Letters, is that it rests solely on measurements and statistical data, including historical records extracted from Antarctic ice, and does not rely on computations with complex climate models.

This work is extremely important for climate change policy, because emission targets to be negotiated at the United Nations Climate Change Conference in Copenhagen early next month have been based on projections that have a carbon free sink of already factored in. Some researchers have cautioned against this approach, pointing at evidence that suggests the sink has already started to decrease. …

Another result of the study is that emissions from deforestation might have been overestimated by between 18 and 75 per cent. This would agree with results published last week in Nature Geoscience by a team led by Guido van der Werf from VU University Amsterdam. They re-visited deforestation data and concluded that emissions have been overestimated by at least a factor of two.” “Controversial new climate change results“

Patrick Michaels’ take
-

“Reference
Paltridge, G., Arking, A. and Pook, M. 2009. Trends in middle- and upper-level tropospheric humidity from NCEP reanalysis data. Theoretical and Applied Climatology: 10.1007/s00704-009-0117-x.

Background
The authors write that “water vapor feedback in climate models is large and positive,” and that “the various model representations and parameterizations of convection, turbulent transfer, and deposition of latent heat generally maintain a more-or-less constant relative humidity (i.e., an increasing specific humidity q) at all levels in the troposphere as the planet warms,” and they say that this “increasing q amplifies the response of surface temperature to increasing CO2 by a factor or 2 or more.” Consequently, knowledge of how q responds to atmospheric warming is of paramount importance to the task of correctly predicting how air temperatures respond to increasing CO2 concentrations.

What was done
Paltridge et al. explored this important subject by determining trends in relative and specific humidity at various levels in the atmosphere based on reanalysis data of the National Centers for Environmental Prediction (NCEP) for the period 1973-2007.

What was learned
The three researchers report that “the face-value 35-year trend in zonal-average annual-average specific humidity q is significantly negative at all altitudes above 850 hPa (roughly the top of the convective boundary layer) in the tropics and southern midlatitudes and at altitudes above 600 hPa in the northern midlatitudes.”

What it means
Paltridge et al. conclude that “negative trends in q as found in the NCEP data would imply that long-term water vapor feedback is negative – that it would reduce rather than amplify the response of the climate system to external forcing such as that from increasing atmospheric CO2.” The ultimate outcome of this dilemma must therefore await a thorough study of the reliability of the pertinent NCEP data, in order to establish, in the words of the three scientists, “what (if any) aspects of the observed [humidity] trends survive detailed examination of the impact of past changes of radiosonde instrumentation and protocol within the various international networks” that collected the globe-spanning data that comprise the NCEP reanalysis archive. And until such an examination is completed, it would foolish in the extreme to forge ahead with any type of “cap and trade” legislation, such as is currently under consideration in the U.S. Senate, or with any international treaties designed to limit anthropogenic CO2 emissions, because the findings of Paltridge et al. suggest that the future warming predicted by today’s climate models may well be far greater than what could actually occur in the real world.” “Tropospheric Humidity and CO2-Induced Global Warming“
-

“The catastrophic fires that are sweeping Southern California are consistent with what climate change models have been predicting for years, experts say …

“This is exactly what we’ve been projecting to happen, both in short-term fire forecasts for this year and the longer term patterns that can be linked to global climate change,” said Ronald Neilson, a professor at Oregon State University and bioclimatologist with the USDA Forest Service … [and] also a contributor to publications of the Intergovernmental Panel on Climate Change, a co-recipient earlier this month of the 2007 Nobel Peace Prize.

“[T]hings just like this are consistent with what the latest modeling shows,” Neilson said, “and may be another piece of evidence that climate change is a reality, one with serious effects.”" “Massive California Fires Consistent With Climate Change, Experts Say“

“As physicists who are familiar with the science issues, and as current and past members of the American Physical Society, we the undersigned urge the Council to revise its current statement* on climate change as follows, so as to more accurately represent the current state of the science:

Greenhouse gas emissions, such as carbon dioxide, methane, and nitrous oxide, accompany human industrial and agricultural activity. While substantial concern has been expressed that emissions may cause significant climate change, measured or reconstructed temperature records indicate that 20th – 21st century changes are neither exceptional nor persistent, and the historical and geological records show many periods warmer than today. In addition, there is an extensive scientific literature that examines beneficial effects of increased levels of carbon dioxide for both plants and animals.

Studies of a variety of natural processes, including ocean cycles and solar variability, indicate that they can account for variations in the Earth’s climate on the time scale of decades and centuries. Current climate models appear insufficiently reliable to properly account for natural and anthropogenic contributions to past climate change, much less project future climate.

The APS supports an objective scientific effort to understand the effects of all processes – natural and human — on the Earth’s climate and the biosphere’s response to climate change, and promotes technological options for meeting challenges of future climate changes, regardless of cause.” “Regarding the National Policy Statement on Climate Change of the APS Council: An Open Letter to the Council of the American Physical Society” h/t IceCap today
-