New results: Arctic pollutants, short-lived species and  
21st century climate, solar forcing of historical climate

Abstract: I'll discuss results from several recent and ongoing  
projects. One study compares how pollution is transported from various  
source regions to the Arctic across many models (in support of the  
Gothenburg Protocol). Another examines the role of projected changes  
in tropospheric ozone and aerosols on 21st century climate, and  
compares the results to the impact of well-mixed greenhouse gases (in  
support of the US CCSP). A third looks at the relative importance of  
emissions from different economic sectors in North America and  
developing Asia. Finally, in ongoing work we are exploring the impact  
of solar variations on climate during the past millenium.