Summary: Every field of science has frontiers. Journalists and activists prefer to show us answers (sometimes guesses), and hide the questions which drive science (and produce much of its excitement). Some are generated by the reigning paradigm, which focuses scientists’ work on key issues. Scientists challenging the paradigm ask different questions, ones often considered irrelevant, unimportant, or unsolvable by the mainstream defenders of the paradigm. In today’s post an eminent climate scientist, a challenger of the paradigm, describes the frontiers as she sees them. {1st of 2 posts today.}
“The science behind climate change is settled, and human activity is responsible for global warming. That conclusion is not a partisan one.”
— EPA Administrator Lisa Jackson to the Senate Environment and Public Works Committee, February 2010 (New York Times). The IPCC says she’s exaggerating, a lot.
What are the most controversial points in climate science?
How might these controversies be resolved?
Judith Curry, posted at Climate Etc, 4 May 2015.
Reposted under her Creative Commons License.
A journalist asked me the questions paraphrased below. It is good to see a journalist asking such questions, when the prevailing view is reflected by this recent Guardian article: “Kofi Annan: We must challenge climate-change skeptics who deny the facts“. If the IPCC were doing its job in the way that I think it should be done, reporters wouldn’t need to ask these questions. In fact the IPCC First Assessment Report (FAR) in 1990 did this well.
Here is my first quick cut at responding to these questions; for reference, I also include the relevant FAR statements.
What are the most controversial points in climate science related to AGW?
There are two overarching issues. Whether the warming since 1950 has been dominated by human causes? How much the planet will warm in the 21st century? More specific, technical issues that need to be resolved in support of addressing these overarching issues…
- Causes of the 1900-1940 warming; the cooling from 1940-1976; and the recent hiatus in warming since 1998. How are these explained in context of AGW being the dominant influence since 1950?
- Solar impacts on climate (including indirect effects). What are the magnitudes and nature of the range of physical mechanisms?
- Nature and mechanisms of multi-decadal and century scale natural internal variability. How do these modes of internal variability interact with external forcing, and to what extent are these modes separable from externally forced climate change?
- Deep ocean heat content variations and mechanisms of vertical heat transfer between the surface and deep ocean.
- Sensitivity of the climate system to external forcing, including fast thermodynamic feedbacks (water vapor, clouds, lapse rate).
- Climate dynamics of clouds: Could changes in cloud distribution or optical properties contribute to the global surface temperature hiatus? How do cloud patterns (and top of atmosphere and surface radiative fluxes) change with shifts in in atmospheric circulation and teleconnection regimes (e.g. AO, NAO, PDO)? How do feedbacks between clouds, surface temperature, and atmospheric thermodynamics/circulations interact with global warming and the atmospheric circulation and teleconnection regimes?
The key areas of scientific uncertainty from the FAR are…
- “Clouds: primarily cloud formation dissipation and radiative properties which influence the response of the atmosphere to greenhouse forcing.”
- “Oceans: the exchange of energy between the ocean and the atmosphere, between the upper layers of the ocean and the deep ocean, and transport within the ocean, all of which control the rate of global climate change and the patterns of regional change.”
- “Greenhouse gases: quantification of the uptake and release of the greenhouse gases, their chemical reactions in the atmosphere, and how these may be influenced by climate change.”
- “Polar ice sheets: which affect predictions of sea level.”
About the FAR list: Clouds and oceans remain as outstanding issues. Progress has definitely been made regarding greenhouse gases and polar ice sheets, although substantial outstanding issues remain particularly re polar ice sheets.
What is the data that provides the greatest challenge to the dominant view of AGW?
- Global data sets of surface temperature and atmospheric temperature (satellite) that show a hiatus in warming for 16+ years.
- Antarctic sea ice data since 1979 (satellite), which shows substantial increase in sea ice extent in recent years.
- Global trends in sea level rise, which show values in the 1930s and 1940’s were comparable to the recent values.
- Recent assessment of lower aerosol forcing lead inescapably to reductions in the estimated upper bound of climate sensitivity.
- The late 20th century divergence between observed surface temperatures and temperatures derived from tree rings.
I could use additional input here, preferably global or hemispheric data sets.
What would provide significant progress in our understanding of the climate?
The primary need is better data, both in the present/future and in the past…
- Historical data archaeology: historical records from written logs or newspaper articles of arctic sea ice extent, sea surface temperatures, extreme weather events, sea level.
- Better paleoclimate proxies: Information is needed on surface temperature, ocean circulation patterns, extreme weather events, rainfall. Most current paleo proxies in use are inadequately calibrated. More research is needed to calibrate existing proxies and develop new proxies. This research should have a rigorous biogeochemical basis.
- Ocean data: It is critical to maintain and enhance the current ocean observing system, both from satellites and in situ measurements. The deep ocean is a key frontier for understanding natural climate variability.
Major theoretical efforts are needed in a number of areas, related to an improved framework for climate sensitivity, networking of the atmosphere and ocean teleconnection patterns, solar indirect effects.
Regarding climate models, I have argued that the current path of climate model development (higher resolution, more chemistry) is not going to improve the present situation whereby the climate models are useless for regional climate variability, decadal variability, and are too sensitive to CO2 forcing.
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(2) About Judith Curry
Judith Curry is Professor of the School of Earth and Atmospheric Sciences at the Georgia Institute of Technology. She is also President and co-owner of Climate Forecast Applications Network (CFAN). Prior to joining the faculty at Georgia Tech, she served on the faculty of the University of Colorado, Penn State University and Purdue University.
She serves on the NASA Advisory Council Earth Science Subcommittee and the DOE Biological and Environmental Science Advisory Committee. She recently served on the National Academies Climate Research Committee and the Space Studies Board, and the NOAA Climate Working Group.
She is a Fellow of the American Meteorological Society, the American Association for the Advancement of Science, and the American Geophysical Union. Her views on climate change are best summarized by her recent Congressional Testimony:
- Rational Discussion of Climate Change: the Science, the Evidence, the Response, Nov 2010.
- Policy Relevant Climate Issues in Context, April 2013.
For More Information
To learn more about these things see The Rightful Place of Science: Disasters and Climate Change
If you liked this post, like us on Facebook and follow us on Twitter. See these Reference Pages for other posts about climate on the FM sites: The keys to understanding climate change and My posts about climate change. Also, see these posts…
- Confronting the Fundamental Uncertainties of Climate Change.
- A look at the cutting edge of the climate sciences, & the lessons we can learn.
- Will a return of rising temperatures validate the IPCC’s climate models?
- A frontier of climate science: the model-temperature divergence by Rud Istvan.
Reblogged this on rennydiokno.com.
This article was very informative, especially her estimates of the strengths and weakness of knowledge in several main areas. Clearly, much more needs to be done By any reasonable estimate the research budget should be doubled. I also liked her mention of a kind of group think in the modelling. Too elaborate in some ways yet probably omitting some important feedback loops. Are we ready for another My Pinatubo event in terms of data collection? Can any historic data such as atmospheric extinction for classical astronomical photometry be used?
Bill,
My recommendations for climate change start as follows…
How many times have you seen this recommendation by those on the Left? By those on the Right? It’s says much about the climate wars that neither side has much interest in more knowledge about this vital subject.
FM, thanks and keep up the good work.. In case you haven’t cited it in previous article(s)
“Climate heretic: Judith Curry turns on her colleagues by Michael D. Lemonick, Scientific American, November 2010 — “Why can’t we have a civil conversation about climate?” Posted at Nature website.
In trying to understand the Judith Curry phenomenon, it is tempting to default to one of two comfortable and familiar story lines.
… In a sense, the two competing storylines about Judith Curry — peacemaker or dupe? — are both true. Climate scientists feel embattled by a politically motivated witch hunt, and in that charged environment, what Curry has tried to do naturally feels like treason — especially since the skeptics have latched onto her as proof they have been right all along. But Curry and the skeptics have their own cause for grievance. They feel they have all been lumped together as crackpots, no matter how worthy their arguments. The whole thing has become a political potboiler, and what might be the normal insider debates over the minutiae of data, methodology and conclusions have gotten shrill. It is perhaps unreasonable to expect everyone to stop sniping at one another, but given the high stakes, it is crucial to focus on the science itself and not the noise.
Eric,
The Sci American article (reposted at Nature) is a remarkable work. The title is wonderfully obtuse: we can’t have a civil conversation about climate when people see it as a religious subject, with their opponents “heretics” instead of fellow scientists.
It shows how scientists often have little understanding of how science works — and less about its history — seeing it instead as a guild.
But that’s a commonplace of history Science works despite the human foibles of its practitioners.
Reblogged this on The Contextual Curriculum™ and commented:
If you change your teaching style do one thing – ASK MORE QUESTIONS!
Reblogged this on Tree-Magazine !.