The Arctic is a beacon of global change. It is where warming has been
strongest over the past century, accelerating over the past decades.
It is an atmospheric receptor of pollution from the northern midlatitudes
continents, as manifested in particular by thick aerosol layers ("arctic
haze") and by accumulation of persistent pollutants such as mercury.
It is increasingly beset by emissions from massive forest fires in boreal
Eurasia and North America. Perturbations to the arctic environment trigger
unique regional responses including melting of ice sheets and permafrost,
decrease in snow albedo due to deposition of black carbon,and halogen
radical chemistry from sea salt aerosols deposited to the ice.
These responses make the Arctic a particularly vulnerable place, subject
to dramatic amplification of environmental change with possibly global
consequences. The urgent need for research to better understand changes
in arctic atmospheric composition and climate is discussed by the Arctic
Climate Impact Assessment (http://amap.no/acia/ ) and the U. S. Global
Change Research Program (http://www.usgcrp.gov). Major research activities
to address this need will take place in 20072008 under the auspices
of the Third International Polar Year (IPY; http://www.ipy.org/ ).
ARCTAS White paper (2.6MB)