by Andrea Saul
A group of 17 American Meteorological Society (AMS) members and renowned scientists has banded together to petition the AMS to include natural variability in their draft statement on climate change (http://www.ametsoc.org/policy/draftstatements/index.html). According to their website, AMS “represents over 11,000 professionals, professors, students, and weather enthusiasts” in promoting “the development and dissemination of information and education on the atmospheric and related oceanic and hydrologic sciences and the advancement of their professional applications.”
These scientists, led by AMS fellow and council member Joseph D’Aleo, submitted their letter yesterday (below) in an effort to influence the deciding committee on the final statement. They are concerned that the current draft statement on climate change “does not adequately address issues that continue about the measurement of past and even current climate and the factors which cause climate changes.”
In the letter, the scientists agree that the draft statement needs to be amended to include “data uncertainty issues,” “additional anthropogenic and natural factors,” and “natural variability when discussing the possibility of continued warming predicated on the imperfect climate models.”
All comments on the AMS statement under consideration are due tomorrow.
December 7, 2006
American Meteorological Society
45 Beacon Street
Boston, MA 02108-3693
Response to AMS Council on the Draft Statement on Climate Change
Dear AMS Council:
The October 20, 2006 AMS draft statement concerning climate change deserves a closer examination.
First of all, we were struck by the remark in the first sentence about the warming of the climate for the last 50 years. In fact, the statement in the relevant IPCC chapter as well as in the technical summary speaks of 30 years. Only the misrepresentation in the IPCC Summary for Policymakers speaks of 50 years.
Overall, the current statement does not adequately address issues that continue about the measurement of past and even current climate and the factors which cause climate changes. As we continue our research and determine the proper policy recommendations, it is important to first address these issues.
There can be no denying our climate is changing or that human activity plays a role, through urbanization and land-use changes around stations as well as greenhouse gases and aerosols. The degree to which climate is changing itself is subject to question. The drop-off of the number of global stations from 6,000 to 2,000 in the last 35 years (with the biggest drop-off in the last 15 years) and the large increase in missing data months in the last decade in some large regions of the world invite some data integrity questions that need to be addressed. A study by Roger Pielke Sr. of Colorado State University, “Unresolved Issues with the Assessment of Multi-Decadal Global Land Surface Temperature Trends” (http://blue.atmos.colostate.edu/publications/pdf/R-321.pdf), which demonstrates the errors in the measurement of surface temperatures with a bias toward warming has been submitted to Journal of Geophysical Research.
A major conclusion of the study is that as a climate metric to diagnose climate system heat changes (i.e., ‘global warming’), the surface temperature trend, especially if it includes the trend in nighttime temperature, is not the most suitable climate metric. As reported in Pielke [BAMS 2003], the assessment of climate heat system changes should be performed using the more robust metric of ocean heat content changes rather than surface temperature trends. If temperature trends are to be retained in order to estimate large scale (including a global average), the maximum temperature is a more appropriate metric than using the mean daily average temperature.
John Lyman and Greg Johnson of NOAA and Josh Willis of the Jet Propulsion Laboratory, California Institute of Technology, in a 2006 GRL paper, “Recent Cooling of the Upper Ocean” (http://www.agu.org/pubs/crossref/2006/2006GL027033.shtml), showed that about a third of the heat gained by the oceans since 1993 disappeared between 2003 and 2005 and that the cooling is “unlikely to be artifacts of inadequate ocean sampling.”
Adjustments are being made for urbanization and local factors in the global data, but the fact that rural areas remain in almost every state and country that show little or no warming (and many areas cooling) raises additional questions about whether these adjustments are of sufficient magnitude. The NCDC HCN data base has the most stability and has been argued the best urban adjustment. It shows a temperature trend that is small (just 0.03C/decade since 1930) and more cyclical in nature, suggesting the role of natural cyclical factors.
Indeed, considerable peer review work has established the important role that the sun, through direct and indirect factors, and multidecadal cycles in the oceans have played in past climate. While the statement mentions solar output, it claims that it probably has had a small impact. In fact in some studies solar and these other factors have been shown to correlate with observed cyclical temperature changes as well as, or better than, greenhouse gases. As for one example, N Scafetta and B. J. West of Duke University, in “Phenomenological Solar Signature in 400 years of Reconstructed Northern Hemisphere Temperature Record” (http://www.agu.org/pubs/crossref/2006/2006GL027142.shtml) (GRL 2006), suggests that the sun might have contributed approximately 50% of the observed global warming since 1900. And Willie Soon in a GRL 2005 paper “Variable Solar Irradiance as a Plausible Agent for Multidecadal Variations in the Arctic-Wide Surface Air Temperature Record of the Past 130 years” (http://www.agu.org/pubs/crossref/2005/2005GL023429.shtml) showed a correlation of 79% of arctic-wide surface temperatures with total solar irradiance from 1880 to 2000 compared to just 22% for greenhouse gases.
Similarly the temperatures over Greenland and the Arctic have been shown to correlate with the phases of Atlantic Multidecadal Oscillation with values as high as 62% over the past century. Greenland temperatures from 1959 to 2003 actually had a negative correlation of -16% with greenhouse concentrations (last two in paper to be presented at Annual AMS).
To limit the debate over current global warming scenarios by virtually ignoring such man made and natural changes is to dangerously mischaracterize the debate. There is not an absolute consensus. There are legitimate alternate viewpoints that deserve recognition.
With such uncertainty as to how much change has occurred and what factors are responsible, it is no easy task to try and project where climate goes from here. We attempt to forecast future climate changes with complex and imperfect climate models. The climate models haven't even convincingly shown whether there will be more or fewer clouds -- which makes their capacity to accurately gauge radiational effects of any change suspect.
In order to develop a policy to correctly anticipate and plan for temperature change we must first develop more accurate future assessment methods which might include a move away from numerical climate models and towards empirically based statistical models. As you may know, a similar evolution occurred in the multi-seasonal forecast realm at CPC.
Let’s not forget the 2001 NAS report that said there is no certainty. Specifically the report said: “Because there is considerable uncertainty in current understanding of how the climate system varies naturally and reacts to emissions… future warming should be regarded as tentative and subject to future adjustment (either upward or downward).”
Nor should you ignore the findings of the 2005 NRC Report “Radiative Forcing of Climate Change: Expanding the Concept and Addressing Uncertainties” (http://www.nap.edu/openbook/0309095069/html/), which concluded a need to move beyond the radiative forcing of CO2, including the need to assess regional radiative and non-radiative climate forcings.
As such, we ask that the draft statement be amended to include references to the following:
-the need to address data uncertainty issues
-the need to discuss additional anthropogenic and natural factors, and
-the need to consider natural variability when discussing the possibility of continued warming predicated on the imperfect climate models.
Thank you for your consideration of our proposed changes. The undersigned are available to discuss this further, and welcome an opportunity for a full and open debate with the committee on this issue.
CCM, Fellow of AMS, Council Member AMS
Executive Director, ICECAP
Dr. Gary Sharp
Center for Climate/ Ocean Resources Study
Dr. Ben Herman, Ph.D.
University of Arizona
Professor and Head of the Department of Atmospheric Sciences
Director of the Institute of Atmospheric Physics; Optical Remote Sensing; Radiative Transfer, Satellite Remote Sensing.
Dr. Richard S. Lindzen
Alfred P. Sloan Professor of Atmospheric Sciences
Massachusetts Institute of Technology
Patrick J. Michaels
Professor of Environmental Sciences
University of Virginia
Past-President, American Association of State Climatologists
Dr. Sallie Baliunas
Harvard-Smithsonian Center for Astrophysics
60 Garden St.
Cambridge MA 02138
Dr. James O’Brien
Robert 0. Lawton Distinguished Professor, Meteorology & Oceanography
Director Emeritus of the Center for Ocean-Atmospheric Prediction Studies
Florida State University
Tallahassee, Florida 32306-2840
Dr. Timothy F. Ball, PhD, Environmental Consultant, Professor of Climatology (Ret'd).
Chairman, Natural Resources Stewardship Project (www.nrsp.com)
205-27 Songhees Road
Victoria, British Columbia, V9A 7M6
Madhav Khandekar, Retd. Scientist Environment Canada
Unionville, ON, CANADA
AMS Member since ~1965
Dr William Gray
Department of Atmospheric Sciences
Colorado Sate University
Fort Collins, CO
Director of Meteorology, News 10NBC
AMS Seal Holder
President, Weather-Track, Inc.
AMS Seal Holder
Peter D. McGurk
BS Atmospheric Science, Cook College, Rutgers University, 1977
SM Geophysics, University of Chicago, 1979
Senior Meteorologist, WSI, Andover MA
Herbert E. Stevens
The Skiing Weatherman and/or Grass Roots Weather
39 Surrey Lane
North Kingstown, RI 02852
Dr. Mel Goldstein
New Haven CT
AMS Seal Holder
160 Wells Ave
Newton MA 02459