Can We Develop A Model That Can Truly Forecast Climate?

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Thursday, 21 January 2010: 3:30 PM
B203 (GWCC)
V. Ramanathan, Univ. of California, La Jolla, CA

I had the pleasure and privilege of working with Warren Washington during the early days on NCAR community climate model development, Warren was then developing his first coupled ocean-atmosphere model, and I was working with Kamal Puri, Eric Pitcher and Bob Malone on the first community climate model-0 (CCM0). It was working with CCM0 that I realized the great need for proper observations for parameterizing complicated physical phenomenon. This took me on a 15 year long detour towards satellite radiation budget measurements and field experiments. These models have now made impressive improvements in the treatment of dynamical and physical processes, and have played a dominant role in raising the importance of the global warming problem. The models results are used as tools for decision making. But the models do not really forecast climate, but simply make projections of assumed scenarios. We are a long way away from making such forecasts, but we have to start; just like Warren started coupling the ocean with the atmosphere in the 70s, even though conventional wisdom claimed we are not ready. As a start, we have to include two important ingredients in the model: explicit treatment of human behavior in the form of consumption; procreation; resource allocation; migration from rural to urban location; economic decisions; adaptation and response to climate change. Next we have to include biology explicitly in the form of exchange of gases and particles with the marine and terrestrial biota and conduct field campaigns to develop and validate model parameterizations. Lastly we have to treat human impact by fuel source. For example, we need to assess the climate impacts of each fuel source and sectors of use. For example, we need an assessment of the impact of coal versus natural gas: Coal emits CO2, which warms the climate but also emits SO2 which cools it. Likewise, the transportation sector is a major source of CO2, but it is also a major source of NOX (a cooling agent).follow the role of coal, by including coal combustion. Lastly we need the models to do proper integrated assessment of new technologies and their role in climate before such technologies (e.g. corn ethanol) are taken to the market.