Climate Science: Roger Pielke Sr. Research Group News

There has been a development over the last 10-15 years or so in the scientific peer reviewed literature that is short circuiting the scientific method.

The scientific method involves developing a hypothesis and then seeking to refute it. If all attempts to discredit the hypothesis fails, we start to accept the proposed theory as being an accurate description of how the real world works.

A useful summary of the scientific method is given on the website sciencebuddies.org.where they list six steps

• Ask a Question
• Do Background Research
• Construct a Hypothesis
• Test Your Hypothesis by Doing an Experiment
• Analyze Your Data and Draw a Conclusion
• Communicate Your Results

Unfortunately, in recent years papers have been published in the peer reviewed literature that fail to follow these proper steps of scientific investigation. These papers are short circuiting the scientific method.

Specifically, papers that present predictions of the climate decades into the future have proliferated. Just a two recent examples (and there are many others) are

Hu, A., G. A. Meehl, W. Han, and J. Yin (2009), Transient response of the MOC and climate to potential melting of the Greenland Ice Sheet in the 21st century, Geophys. Res. Lett., 36, L10707, doi:10.1029/2009GL037998.

Solomon, S. 2009: Irreversible climate change due to carbon dioxide emissions. The Proceedings of the National Academy of Sciences. Published online before print January 28, 2009, doi: 10.1073/pnas.0812721106

Such studies are even reported in the media before the peer reviewed process is completed; e.g. see in the article by Hannad Hoag in the May 27 2009 issue of Nature News Hot times ahead for the Wild West.

These studies are based on models, of which only a portion of which represent basic physics (e.g. the pressure gradient force, advection and the universal gravitational constant), with the remainder of the physics parameterized with tuned engineering code (e.g see).
 

When I served as Chief Editor of the Monthly Weather Reviews (1981-1985), The Co-Chief Editor of the Journal of Atmospheric Sciences (1996-2000), and as Editor-in-Chief of the US National Science Report to the IUGG  for the American Geophysical Union (1993-1996), such papers would never have been accepted.

What the current publication process has evolved into, at the detriment of proper scientific investigation, are the publication of untested (and often untestable) hypotheses.  The fourth step in the scientific method “Test Your Hypothesis by Doing an Experiment” is bypassed.

This is a main reason that the policy community is being significantly misinformed about the actual status of our understanding of the climate system and the role of humans within it.

SECOND UPDATE: See the May 20 2009 article by Jayne O’Donnell and James R. Healey in USA Today titled

“Safety could suffer if we boost mileage by making cars smaller”

Updated pm May 19 for clarity at the beginning of the first sentence of the paragraph below the bullets

Today, President Obama is announcing the establishment of a new car fuel mileage standard of 35.5 miles per gallon ( see Automakers, Obama announce mileage, pollution plan by Ken Thomas and Philip Elliot).  Their article includes the new framework for this standard where they report

“Historically, the program was a fleet average,” said Browner, who headed the EPA during the Clinton administration. “What we’re doing here is proposing standards for every category of car.”

 This increase in the standard could be achieved by one or more of the following:

• technology could improve the efficiency of the combustion process
• technology could provide/permit the use of alternative energy sources such as hybrid and electric engines
• vehicles could be made smaller and/or lighter

The first approach would use the current type of combustion engine and make it even more efficient than it is at present. The second method reduces tailpipe emissions of the combution products from the vehicle, although the emissions from the source of the energy (i.e. power plants) needs to be included in the assessment of mileage. The third approach could use lighter materials to build the cars and/or they could be made smaller.

I agree that the technology improvements in the first two bullets would be a win-win for both the environment and for the reduction of the import of foreign energy sources, and should be achievable without a reduction in safety.

However, if the approach is just to make cars smaller and/or lighter, the potential increase in injuries and deaths as a result makes this a poor approach; e.g. see

Another Example Of An Environmental Tradeoff - Reduced CO2 Emissions And Lower Fuel Cost Versus Personal Safety

Congress should require that the fuel standard not be achieved by simply reducing the size and/or weight of cars, but through technology improvements.

The Washington Post published an article on March 24 2009 by Juliet Eilperin entitled “EPA Presses Obama To Regulate Warming Under Clean Air Act” in which is is written

“The Environmental Protection Agency’s new leadership, in a step toward confronting global warming, submitted a finding that will force the White House to decide whether to limit greenhouse gas emissions under the nearly 40-year-old Clean Air Act. Under that law, EPA’s conclusion — that such emissions are pollutants that endanger the public’s health and welfare — could trigger a broad regulatory process affecting much of the U.S. economy as well as the nation’s future environmental trajectory.”

While the added greenhouse gas emissions (does the EPA also include water vapor?) are a climate forcing,  the news article specifically refers to public health. This is an absurd claim, as none of the well-mixed greenhouse gases are threats to health at the concentrations that are in the atmosphere or will be in the atmosphere far into the future.

If the EPA wants to seek to regulate climate, let them be honest and discuss all of the human climate forcings, as discussed, for example, in

National Research Council, 2005: Radiative forcing of climate change: Expanding the concept and addressing uncertainties. Committee on Radiative Forcing Effects on Climate Change, Climate Research Committee, Board on Atmospheric Sciences and Climate, Division on Earth and Life Studies, The National Academies Press, Washington, D.C., 208 pp.

 Another excerpt from the Washington Post article reads

“Daniel J. Weiss, a senior fellow at the Center for American Progress, a liberal think tank, said the EPA’s proposal would allow the administration to tackle climate change if Congress does not limit carbon emissions through legislation. He added that even if the EPA were forced to regulate greenhouse gases, it would target emissions from coal-fired power plants and then vehicles — which combined account for about half of the nation’s global-warming pollution — before requiring smaller operations to apply for new emissions permits.”

The statement “smaller operations” could include almost all activities that humans do; e.g. see

 A Carbon Tax For Animal Emissions - More Unintended Consequences Of Carbon Policy In The Guise Of Climate Policy

The EPA’s plan “to regulate warming” is a circumvention of science in order to promote a political agenda. Serious negative environmental, economic and social effects are going to occur as a result of the inappropriately narrow and ineffective EPA focus on greenhouse gas emissions as the currency for a wide range of climate effects.

There have rather puzzling recommendations made recently in which improvements in air quality are recommended as being delayed in order to retain the radiative cooling effect of certain aerosols, particularly sulphates. Examples of such a recommendation are reported in the Climate Science weblogs

A Excellent Seminar At The University of Colorado at Boulder “What Goes Around Comes Around” By Gregory R. Carmichael

Further Comments on the Question “Can The Climate System ‘Mask’ Heat?”

Misconception And Oversimplification Of the Concept Of Global Warming By V. Ramanthan and Y. Feng

This recommendation is made despite evidence presented in the first weblog listed above, for example, that “350,000 excess deaths per year in India and China due to outdoor exposure risk for each 20mg/m3 (of fine aerosols of less than 2,5 microns).”   Such a recommendation applies to all types of aerosols which includes aerosols that contribute to radiative cooling (e.g. see Chapter 2 in the 2007 IPCC report and Chapter 2 in the 2005 NRC report for reviews of these negative radiative forcings).

I have worked throughout my career to improve air quality. This includes two terms on the Colorado Air Quality Control Commission where we implemented (and I supported) efforts such as the oxygenated fuels program to reduce atmospheric CO, strictregulations on wood and coal burning in residential fireplaces and stoves, and on asbestos concentrations. I was a member of an NRC committee that rejected an attempt to exempt certain locations such as Fairbanks Alaska from the national CO health standard; see

National Research Council, 2003: Managing carbon monoxide pollution in meteorological and topographical problem areas. The National Academies Press, Washington, DC, 196 pp,

and also an NRC committee to communicate the major concerns of overgrazing, which includes an increase in dust emissions into the atmosphere; see

Committee on Scholarly Communication with the People’s Republic of China, 1992: Grasslands and grassland sciences in Northern China, Office of International Affairs, National Research Council, National Academy Press, Washington, D.C., 214 pp.

I have taught graduate classes in air pollution at the University of Virginia and Colorado State University (even a class on the U.S. Wilderness System in which the preservation of pristine air quality is a major issue that we discussed).  I also was on  a committee in Fort Collins that mandated that the permit to construct and operate a brewrey near the city require the burning of natural gas rather than coal.

The motivation for all of these activities is to reduce human mortality and morbidity and to minimize negative environmental effects from air pollution.  

Thus, when I see attempts to delay implementation of any air quality improvement, which will cost lives, in order to provide a climate effect (i.e. through the delay in reducing sulphate emissions), we need to recognize that the priorities of those making such climate recommendations are misplaced.

The weblogs ICECAP and Watts Up With That have alerted us to the plan to list carbon dioxide as a pollutant by the EPA where they report on an article titled “Obama to Declare Carbon Dioxide Dangerous Pollutant” by Jim Efstathiou Jr. of Bloomberg.

Climate Science has weblogged on this subject in the past; see

Will Climate Effects Trump Health Effects In Air Quality Regulations?

Supreme Court Rules That The EPA Can Regulate CO2 Emissions

Science Issues Related To The Lawsuit To The Supreme Court As To Whether CO2 is a Pollutant

What the listing of carbon dioxide as a pollutant would do is to implicitly declare that any human activity that affects climate could be considered a pollutant. This would logically mean, for instance,  that the EPA could regulate land use since, as extensively documented in the peer reviewed literature (e.g. see), landscape change is a human climate forcing.

This plan to regulate CO2 as a pollutant (since it is a human climate forcing) would give them the legal rationale to permit the implementation of additional federal regulations for other human climate forcings including the zoning of how land is developed.  Everyone should realize the implications and significance of this potential expansion of federal authority.  There may be societal benefits to such broad climate regulation authority, however, this issue should be more effectively discussed and debated than it has been up to the present.

UPDATE: It has been pointed out to me that the EPA does not have the “legal” rationale (i.e. precedent or law) to permit the  implementation of additional federal regulations for other human climate forcings. Hence, I have removed”legal” (by the strike out).

Thanks to Timo Hämeranta for alerting us to the essay by the internationally well respected climate scientist Ann Henderson-Sellers on September 17 2008 titled “The IPCC report: what the lead authors really think”. It is worth reading and I have reproduced below:

 “In the final months of the Intergovernmental Panel on Climate Change’s Fourth Assessment reporting in 2007, the world’s three leading climate science agencies asked people directly and intimately involved with the report for their views on how the process had gone and some of the key issues it raised.

About the author

Ann Henderson-Sellers holds an Australian Research Council Professorial Fellowship in the Climate Risk CORE of Macquarie University. Until 2007 she was the Director of the World Climate Research Programme based in Geneva at the headquarters of the World Meteorological Organisation.”

There are quite interesting confessions within this essay! These include

The rush to emphasize regional climate does not have a scientifically sound basis

Until and unless major oscillations in the Earth System (El Nino-Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO), North Atlantic Oscillation (NAO) and Atlantic Multidecadal Oscillation (AMO) etc.) can be predicted to the extent that they are predictable, regional climate is not a well defined problem. It may never be. If that is the case then we should say so. It is not just the forecast but the confidence and uncertainty that are just as much a key.

Climate models need to be exercised for weather prediction; there are necessary but not sufficient things that can best be tested in this framework, which is just beginning to be exploited.

Energy budget is really worrisome; we should have had 20 years of ERBE [Earth Radiation Budget Experiment] type data by now- this would have told us about cloud feedback and climate sensitivity. I’m worried that we’ll never have a reliable long-term measurement. This combined with accurate ocean heat uptake data would really help constrain the big-picture climate change outcome, and then we can work on the details.
 

The Economist published an article this past week titled “Adapt or die” [subscription needed]. It is an informative article and starts to address the issue of vulnerability that has been emphasized on Climate Science (e.g. see).

A focus on critical resources (e.g. energy, food, water, medical support) which is local and regionally focused, is a much more effective framework to assist society in reducing the risks from the diverse range of threats that face society and the environment.  This resource based emphasis is a much needed replacement to the almost exclusive focus on downscaling from multi-decadal global models as promoted using the IPCC and CCSP perspectives.

There are a two glaring errors, however, in the Economist article. The first is their statement that two things have changed attitudes towards adapation;

“One is evidence that global warming is happening faster than expected. Manish Bapna of the World Resources Institute, a think-tank in Washington, DC, believes ‘it is already too late to avert dangerous consequences, so we must learn to adapt.’”

and

“Second, evidence is growing that climate change hits two specific groups of people disproportionately and unfairly. They are the poorest of the poor and those living in island states: 1 billion people in 100 countries.”

The author(s) of the Economist article have ignored that global warming has actually halted, at least for now. The upper ocean heat content data indicates that there has been no warming since 2004 (see), while the tropospheric temperature data indicates no warming for about 7 years (e.g. see Figure 7).  Global warming is actually “happening more slowly than expected”.

With respect to the second comment, climate has always affected the poor more significantly than the rich. Climate variability has always been a major issue in those societies in which their food, energy, water and health facility infrastructures are underdeveloped. These poor societies face threats from famine and disease regardless of the role of humans within the climate system! Adaptation is common sense and should be a much higher priority than it has been given. The IPCC emphasis on CO2 as the reason for increased risk ignores the need for a much broader perspective to reduce vulnerability. A more inclusive framework is presented in Chapter E in the IGBP book 

Kabat, P., Claussen, M., Dirmeyer, P.A., J.H.C. Gash, L. Bravo de Guenni, M. Meybeck, R.A. Pielke Sr., C.J. Vorosmarty, R.W.A. Hutjes, and S. Lutkemeier, Editors, 2004: Vegetation, water, humans and the climate: A new perspective on an interactive system. Springer, Berlin, Global Change - The IGBP Series, 566 pp

See, for example, the first paragraph in

Pielke, R.A. Sr., and L. Bravo de Guenni, 2004: Conclusions. Chapter E.7 In: Vegetation, Water, Humans and the Climate: A New Perspective on an Interactive System. Global Change - The IGBP Series, P. Kabat et al., Eds., Springer, 537-538.

Thus, while the Economist article is a good start, the authors should recognize that a local and regional focus on societal and environmental vulnerability is a much more effective framework to reduce the threats that humanity and the environment face, than to rely on multi-decadal global model predictions.

Comment Submitted to Dot Earth by Roger A. Pielke Sr.

The conflict between a top-down global model (IPCC) perspective and a bottom-up resource vulnerability focus is clearly illustrated by the NCAR/UCAR priorities of Rick Anthes and Kevin Trenberth regarding the physical and social sciences.

Rick Anthes and Kevin Trenberth (both of whom I know quite well) are excellent research scientists who have also strongly advocated for the top-down model driven framework. This is why they accept the viewpoint  “that global warming is unequivocal”, and see the models as the uniquely qualified mechanism to deliver information on the future climate to the social science community.

Climate Science has weblogged on this issue at http://climatesci.org/index.php?s=anthes&submit=Search, where I wrote

“Climate Science…..has recommended an inversion of the focus where the first step is to identify local and regional vulnerabilities to key resources (e.g. food, energy, water) to determine the magnitude of changes in climate and other environmental conditions that would result in a negative effect on these essential resources. We do not need a global climate model prediction to do this! Rather, we need the involvement of the social science community, which NCAR, under the direction of Rick Anthes, has elected to cut.

This was a short sighted decision which is clearly based on focusing funds in order to support greater computing and observational power. While Climate Science agrees that funds are needed to improve our understanding of the climate system on decadal time scales (the assessment of model predictability; the use of climate models and observations for process studies and diagnostic analyses;…), a significant amount of funds should be allocated for the assessment of societal and environmental vulnerabilities. NCAR’s (and UCAR’s) decision to cut the social science program at NCAR has removed an effective program to examine these vulnerabilities.”

The advantages of the vulnerability approach, as contrasted with the GCM climate model downscaling is summarized in Table E.7

in

Pielke, R.A. Sr., and L. Bravo de Guenni, 2004: Conclusions. Chapter E.7 In: Vegetation, Water, Humans and the Climate: A New Perspective on an Interactive System. Global Change - The IGBP Series, P. Kabat et al., Eds., Springer, 537-538.

The removal of an outstanding social scientist, Mickey Glantz, is clear evidence that Rick Anthes and Kevin Trenberth do not see the vulnerability bottom-up resource framework as a priority activity at NCAR.

The recent firings at NCAR in the area of social sciences (see) highlights a conflict between those who have concluded that a top-down global climate model perspective provides more useful information to policymakers than does a bottom-up resource-based vulnerability perspective. The bottom-up perspective, however, is more inclusive and useful to policy makers.  For example, see

Pielke, R.A. Sr., 2004: Discussion Forum: A broader perspective on climate change is needed. IGBP Newsletter, 59, 16-19

which is based on the detailed review in the book

Kabat, P., Claussen, M., Dirmeyer, P.A., J.H.C. Gash, L. Bravo de Guenni, M. Meybeck, R.A. Pielke Sr., C.J. Vorosmarty, R.W.A. Hutjes, and S. Lutkemeier, Editors, 2004: Vegetation, water, humans and the climate: A new perspective on an interactive system. Springer, Berlin, Global Change - The IGBP Series, 566 pp.

Dr. Richard Anthes, UCAR President, recently published an article in the President’s Corner  in the UCAR Quaterly entitled Mitigate and adapt­—but don’t forget the science!

This article documents that the UCAR President (who oversees NCAR) is a strong advocate of the top-down perspective and wants significant additional funding for this.  Several excerpts from the article are

“In spite of remarkable progress over the past several decades, our understanding of the complex physical, chemical, and biological Earth system and its interactions with humans remains, on many levels, rudimentary. We’ve identified many research questions where there is more that we don’t know than we do. And there are certainly still more questions we don’t yet even know we should be asking. Even the feedbacks in the Earth system that we recognize as important in a qualitative way are just beginning to be understood in quantitative ways that can be included in weather, climate, and Earth system models. “

“In order to monitor, understand, predict, and adapt to climate change—including the all-important changes in extreme and impactful weather on local and regional scales, where it really counts—we have a long way to go. Now more than ever, we need better Earth observations, increased computer power to process the observations and run the models, improved weather and climate predictions, and enhanced research on how weather and climate affect social order and life on the planet.”

“Calls for more funding are a familiar aspect of science. What many observers may not realize is that, in recent years, the nation’s investments in the key areas listed above have been decreasing in real dollars.”

“There is also no substitute for computing power to understand and predict weather and climate. Larger and faster computers allow scientists to effectively combine the suite of diverse global observations into a meaningful whole and to make predictions and warnings with increasing accuracy and detail for local areas. Ever more powerful computers will be needed to build and run Earth system models that contain biological and chemical processes and human interactions. These advanced models will be essential tools in both understanding and predicting climate change and in societal demands for information. Yet computing power at major climate modeling centers such as NCAR is increasing in a business-as-usual way that does not reflect the importance of the science and the need for vastly improved decision support tools related to climate and weather.”

“Beyond the intellectual challenges they pose, climate and weather changes stand to affect almost every part of our society: public health and safety, economic and social stability, agriculture, water supplies and management, energy production and use, transportation, and military readiness. In each of these areas, policy- and decision makers are clamoring for concrete guidance on what to expect as our climate and weather evolve and how to adapt to changes. For example:

• What kinds of crops are best suited to hotter, more drought-prone areas?
• How might rising sea level, intensified rainfall, and changes in hurricanes affect cities along the Gulf and Atlantic coasts?
• How long will it take for the Arctic Ocean to experience ice-free conditions in summer?
• How will energy and water demands and supplies change in my city, state, or region?”

“In addressing these and other key questions, scientists must provide quantitative as well as qualitative information at ­increasingly regional and local scales. We need to work with users to understand what might happen, what will almost certainly happen, and where the science has yet to support firm conclusions. With increased computing and modeling power, we can expand the type of ensemble climate modeling systems that are beginning to tackle questions on the regional level, such as:

• What scenarios are possible? Most likely?
• What are the worst and best cases?
• What are the probabilities of the different scenarios?
• How can we quantify the risks associated with various contemplated courses of action?”

“Our current ideas on how to deal with climate change rest on a scientific foundation that remains only partially built. Especially when it comes to large-scale mitigation efforts, we may know just enough to be dangerous. People will inevitably make choices based on today’s far-from-complete scientific knowledge (society cannot stand still while we do our work), but we must learn more.”

“Enhanced observations of Earth are needed to validate and improve climate models, support more accurate and precise predictions, confirm or deny these predictions, and detect surprises. Physical as well as social scientists must listen to stakeholders, map out our vulnerabilities to extreme weather, and learn how to increase society’s flexibility and resilience in the face of a climate never before experienced by humans. And we must develop the advanced models that can greatly improve our forecasting and warning systems and sharpen our look into the future.”

“Will we as a community be able to meet these national needs? As a result of budget battles between the White House and Congress, federal funding for climate, weather, and other Earth science research at NASA, NOAA, and NSF will drop in real terms this year—for the fourth year in a row—while our ability to monitor Earth’s vital signs begins to decline.”

“Future leaders in the White House and Congress will be forced to juggle many priorities. If climate change ranks among the top threats facing our planet, as I and many others believe, then it seems imperative that we invest in observing, understanding, and predicting our climate at a level commensurate with the risk we face, while at the same time carrying out unprecedented mitigation and adaptation efforts on a local, national, and global basis.”

Anthes statement that

“…climate and weather changes stand to affect almost every part of our society: public health and safety, economic and social stability, agriculture, water supplies and management, energy production and use, transportation, and military readiness. In each of these areas, policy- and decision makers are clamoring for concrete guidance on what to expect as our climate and weather evolve and how to adapt to changes’

illustrate the top-down focus that he espouses in that he assumes

“policy- and decision makers are clamoring for concrete guidance”

and that

“Larger and faster computers allow scientists to effectively combine the suite of diverse global observations into a meaningful whole and to make predictions and warnings with increasing accuracy and detail for local areas.”

His statement that

“Physical as well as social scientists must listen to stakeholders, map out our vulnerabilities to extreme weather,…”

reflects his view that the global climate models [downscaled to local areas] provide “forecasts” to the “stakeholders” who then determine their vulnerabilties to these predictions. This, however, continues to make the modeling community the driver of the assessment process rather than just one partner in the information used by the stakeholders! The reliance on the multi-decadal global models to predict future climate also seriously limits the range of the assessment of consequences to society and the environment to what actually will occur in the coming decades, since we know these global models are still inadequate, as even Anthes has admitted in his article and as seen in real world data (e.g. see)!

Climate Science, in contrast, has recommended an inversion of the focus where the first step is to identify local and regional vulnerabilities to key resources (e.g. food, energy, water) to determine the magnitude of changes in climate and other environmental conditions that would result in a negative effect on these essential resources. We do not need a global climate model prediction to do this! Rather, we need the involvement of the social science community, which NCAR, under the direction of Rick Anthes, has elected to cut.

This was a short sighted decision which is clearly based on focusing funds in order to support greater computing and observational power. While Climate Science agrees that funds are needed to improve our understanding of the climate system on decadal time scales (the assessment of model predictability; the use of climate models and observations for process studies and diagnostic analyses; see), a significant amount of funds should be allocated for the assessment of societal and environmental vulnerabilities. NCAR’s (and UCAR’s) decision to cut the social science program at NCAR has removed an effective program to examine these vulnerabilities.

An oligarchy is a

“form of government in which all power is vested in a few persons or in a dominant class or clique; government by the few.”

This definition certainly fits with the IPCC, as illustrated by the closed meeting in which Gerald Meehl, Jonathan Overpeck, Susan Solomon, Thomas Stocker, and Ron Stouffer are organizing in Hawaii in March 2009. This meeting is reported at

Joint IPCC-WCRP-IGBP Workshop: New Science Directions and Activities Relevant to the IPCC AR5 [Tuesday, March 03, 2009 - Friday, March 06, 2009 at the University of Hawaii International Pacific Research Center Honolulu , Hawaii].

While the meeting is to be mostly self-funded [which means federal contracts and grants and other such sources will be used to pay for the trip], it raises the issue as to why such a remote location is chosen. Presumably the particpants should be concerned about the emission of CO2 into the atmosphere from the jet aircraft that will transport them to Hawaii.

The Workshop is also open to only the IPCC Working Group 1 Lead Authors [LAs] and Contributing Lead Authors [CLAs] from all four assessments.  While the goals of the Workshop are appropriate scientific topics, the closed character of the Workshop and its location perpetuates the exclusiveness of the IPCC process.  

This small community of climate scientists is controlling the agenda with respect to the assessment of climate change. This is an oligarchy.

Climate Science urges that a new group of climate scientists be empowered to lead the next IPCC report. The inbred group of scientists who are to attend the Hawaii workshop, while most are excellent scientists, have a conflict of interest in that they have already presented their viewpoints on the role of humans in the climate system [at the expense of excluding peer reviewed science viewpoints, however; eg. see the Appendix in Pielke 2008].

The next IPCC assessment should involve only scientists who have not taken a strong position on the IPCC reports, but who have outstanding scientific credentials. Among the first questions they should address are the three hypotheses, only one of which can be true;

This research question has been discussed on Climate Science (e.g. see).

Without new scientists leading the IPCC process as LAs and CLAs, the next IPCC report is doomed to continue to be completed by an oligarchy that is using its privileged position to advocate for a particular perspective on the role of humans within the climate system [the third hypothesis above]. The next IPCC report will not be a balanced assessment, but continue to be policy advocacy in the guise of a scientific framework.