Predicting Global Warming ENVS 110 ( )

Source: Commonwealth of Australia 2006, Bureau of Meteorology (ABN ) (accessed 3/13/06)

How to Make Climate Predictions ? Climate Models –very simple energy balance models –more complicated general circulation models (GCM’s) –what to include –what to leave out –how do feedback’s work

Some Modeling Problems: generally low level of scientific understanding timescales involved high spatial resolution required to obtain “useful” results computationally expensive

GCM’s: The Hard-Core Approach

source: Hadley Center, The MET Office

“Low-Tech” Approach make very few assumptions about importance of forcings and feedbacks keep the math simple (relatively speaking) fast model, can do many runs, try many things can pick “best” result how to decide on “best” result?

source: Knuti et al., nature 2002

Comparison of two Approaches

Results of Climate Models all models predict a rise in temperature due to an increase in atmospheric CO 2 increase most severe in high latitudes –melting of polar ice caps –sea level rise –global cooling ? changes in precipitation, soil moisture

Results of Climate Modeling From Mitchell et al., 2001

So, who cares ? societal concerns (economic hardship) ecological concerns (survival of other species, ecosystems – why is this a problem ?) ethical concerns (who will be affected the most?) is global warming by definition a bad thing?

the underlying problem…

population growth rates