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GFDL Milestones 3rd Quarter, FY01
Report on the key findings of, and the contributions of GFDL to, the IPCC 2001 climate change assessment.(R J. Stouffer)
Quarter FY01
GFDL continued its tradition of making substantial contributions to the IPCC process. Recently, the Third Assessment Report ( TAR ) of the Intergovernmental Panel on Climate Change (IPCC) was completed. GFDL scientists were involved as reviewers and contributors to a number of the chapters in the report. In addition, papers produced by GFDL scientists were cited throughout the report. Two GFDL scientists were lead authors of two different chapters in the report and played a leading role in the development of the Technical Summary and the Summary for Policymakers.
The TAR is an assessment of the climate change science focusing on the new developments of the past 5 years. It involves the participation of several hundred climate scientists from the worldwide climate community. The major findings of this report are as follows:
- "An increasing body of observations gives a collective picture of a warming world and other changes in the climate system."
- "Emissions of greenhouse gases and aerosol due to human activities continue to alter the atmosphere in ways that are expected to affect the climate."
- "Concentrations of atmospheric greenhouse gases and their radiative forcing have continued to increase as a result of human activities."
- "Confidence in the ability of models to project future climate has increased."
- "There is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities."
Science from GFDL is prominent in two main areas of the report. One is the assessment of the effect of the changes in concentration of the various gases and aerosols on the radiative forcing of climate, including the detailed study of the relationship of the concentrations to those forcings. This maps directly into the major findings of the TAR (#2 and #3 above).
The second area is the use of coupled model results for:
- the assessment of the natural variability of climate
- the assessment of the observed climate changes over the past 150 years
- the projection of climate change into the future. This maps directly into #4 and #5 of the major findings of the TAR. Both of these areas have long been strengths of GFDL research.
In addition, there are many topics where GFDL research is used to increase understanding, but where uncertainties remain. For example, most models show that the global thermohaline circulation ( THC ) in the world's oceans weakens as the greenhouse gases increases. Companion studies at GFDL and Max Planck Institute for Meteorology investigated the physical mechanisms for the weakening of the THC. These studies found that the mechanisms responsible for the weakening are different in the two models, giving some indication of the uncertainty about this issue. While not leading to conclusions today, this type of research does lay the groundwork for future advances by increasing our understanding.
In summary, GFDL scientists and research were important in producing the Third Assessment Report from the IPCC. These facts highlight the impact that the science produced at GFDL is having on our society.