KEYNOTE ABSTRACT: Oceans, ice and atmosphere

• Main Authors: Educational Challenges, Julienne Stroeve, National Snow
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2009
• Subjects: Arctic; Climate change; Sea ice
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.530.5450; http://www.unesco.org/csi/LINKS/monaco-abstracts/Stroeve_Keynote_abstract_MonacoUNESCOarctic.pdf

Arctic sea ice extent has declined over the past several decades, showing downward trends in all months, with the smallest trends in winter and the largest trends at the end of the melt season in September [Serreze et al., 2007]. However, the rate of decline is accelerating. In 2001, the linear trend in September monthly mean extent over the available satellite (1979 to present) record stood at-7.0 % per decade. By 2006, it had increased to-8.9 % per decade. Then, in September 2007, Arctic sea ice extent fell to the lowest value ever recorded, 23 % below the previous record minimum set in 2005, boosting the downward trend further to-10.7 % per decade [Stroeve et al., 2008]. Including September 2008, which ended up as second lowest in the satellite record, the trend stands at-11.8 % per decade (Figure 1). All coupled global climate models used in the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4) show declining September ice extent over the period of observations [Stroeve et al., 2007; Zhang and Walsh, 2006]. Although this is strong evidence for a role of greenhouse gas (GHG) forcing on the observed trend, the simulated trends, as a group, are smaller than observed. This finding has raised