The Arctic cryosphere in the Mid-Pliocene BRIDGE, School of Geographical Sciences, University of Bristol

• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2008
• Subjects: Pliocene; ice sheets; cryosphere; Greenland; palaeoclimate; Arctic; arctic cryosphere; Climate change; Ice Sheet
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.667.7893; http://rsta.royalsocietypublishing.org/content/roypta/367/1886/49.full.pdf

The Mid-Pliocene (ca 3 Myr ago) was a relatively warm period, with increased atmospheric CO2 relative to pre-industrial. It has therefore been highlighted as a possible palaeo-analogue for the future. However, changed vegetation patterns, orography and smaller ice sheets also influenced the Mid-Pliocene climate. Here, using a general circulation model and ice-sheet model, we determine the relative contribution of vegetation and soils, orography and ice, and CO2 to the Mid-Pliocene Arctic climate and cryosphere. Compared with pre-industrial, we find that increased Mid-Pliocene CO2 contributes 35 per cent, lower orography and ice-sheet feedbacks contribute 42 per cent, and vegetation changes contribute 23 per cent of Arctic temperature change. The simulatedMid-PlioceneGreenland ice sheet is substantially smaller thanthatofmodern,mostlydue to thehigherCO2.However, our simulations offuture climate change indicate that the same increase in CO2 is not sufficient tomelt the modern ice sheet substantially. We conclude that, although the Mid-Pliocene resembles the future in some respects, caremust be takenwhen interpreting it as an exact analogue due to vegetation and ice-sheet feedbacks. These act to intensify Mid-Pliocene Arctic climate change, and act on a longer time scale than the century scale usually addressed in future climate prediction.