Seeing the Forest: Greenhouse Gases (Invited Presentation)

Weather forecasting depends on tracking day-to-day changes in jet streams, fronts, vorticity, CAPE, and vertical velocity. Weather is inherently unpredictable beyond a week or two. Climate doesn't depend on these things. Rather, it depends on heat budgets at the top of the atmosphere, which are much more predictable than the vagaries of weather. When changes in energy budgets are both predictable and strong, then the responses to this forcing is also predictable. Examples include the seasonal cycle, differences between Miami and Minneapolis, and the impacts of very strong El Nino events. Changes in the energy budget due to enhanced absorption of thermal radiation by CO2 are both strong and predictable, so the effects of these changes on climate are predictable in a way that weather is not. Even without changes in weather patterns, we expect major changes in the frequency of extreme high temperatures, rainfall, drought, and coastal flooding over coming decades due to the strong and predictable changes in planetary radiation that arise from extra CO2.

Seeing the forest instead of the trees. Dr. Scott Denning will talk about climate research and how to step back and understand the overall picture of how greenhouse gases are and will impact our weather and climate.