To prepare for managing the transition to an Arctic that may be nearly ice free during summer, it is critical to have accurate projections of Arctic environmental changes over the next several decades. Forecasts of regional sea-ice conditions on seasonal timescales can help different stakeholders prepare for and adapt to the impacts of climate change and minimize environmental risks associated with development. While the Intergovernmental Panel on Climate Change (IPCC) models provide meaningful projections of future global temperature and precipitation, projections of Arctic sea ice cover range widely, from almost no change to the end of the 21st century, to a disappearance of the ice cover at the end of summer 20 years from now.
Clouds (Figure 1.2, top figure) exert the strongest forcing on the surface heat balance, which controls the freezing and melting of ice (Kay et al., 2008; Curry et al., 2006). In view of several other uncertainties concerning sea ice physics, it is not surprising that the models show a huge variance in their predictions of the Arctic ice cover during the rest of our century.