During the past few decades, Arctic temperatures have increased while annual and seasonal Arctic Ocean sea ice cover has decreased, leading to greater coastal erosion, changes in marine ecosystems, habitats, and productivity, and greater export of freshwater, among other trends. Of particular concern is the decrease in Arctic sea ice extent and thickness since 1979, especially during summer months, which has outpaced the rates predicted by climate models. Because instrumental records extend back only a few decades and there is large interannual and decadal variability, the causes of ongoing Arctic climate change remain unclear. Moreover, atmospheric carbon dioxide concentrations are approaching levels not seen in 3 million years. Thus, there is a growing need to understand how the Arctic Ocean responds to climate change caused by both natural and anthropogenic factors.
Paleoclimatological records show that the Arctic experienced major climate changes over timescales ranging from tens of millions of years to decades. Studying paleoclimate records preserved in Arctic Ocean sediments can improve understanding of the patterns and causes of Arctic climate change over all timescales and shed light on possible future climate change and its impacts. For example, paleoclimate reconstructions from land areas and glaciers in the Arctic suggest that recent atmospheric warming has reversed regional trends of the last few millennia, which showed a cooling Arctic climate (Kaufman et al., 2009). A long-term investment in basic research prepares us to address questions about Arctic climate change.
The Arctic paleoceanography project uses evidence from Arctic Ocean sediments to reconstruct climate and sea ice history for the Arctic Ocean and adjacent seas. Dr. Thomas M. Cronin, Project Chief.
References Cited
Kaufman, D. S., D. P. Schneider, N. P. McKay, C. M. Ammann, R. S. Bradley, K. R. Briffa, G. H. Miller, B. L. Otto-Bliesner, J. T. Overpeck, B. M. Vinther, and Arctic Lakes 2k Project Members. 2009. Recent Warming Reverses Long-Term Arctic Cooling. Science 325, 1236-1239.
