2030 relative to 2005. Figure 6.2 illustrates two key issues for Arctic operations. First, the sea-ice projections from climate models today are so broad that clearly a risk management approach is needed. Second, about one-quarter of the models project faster decline in the next 20 years than has been observed during the satellite era. The two models that agree with observations during the satellite era have above-average decline among models in the future. These same two models have ice-free conditions (i.e., the area falls below 1 million square kilometers) in September by roughly the years 2040 to 2060.

The spotlight on sea-ice projections from the last IPCC report (AR4) is likely to cause a step-change improvement in sea-ice modeling. The most profitable avenue of improvement is likely to be realized from improving the sea-ice climatology through tuning the model, as the climatology has been shown to have a substantial bearing on the subsequent trend.29,30 There is likely to be substantial value from improving processes in the sea-ice component as well.31

Stimulated by the magnitude of Arctic climate change since the mid-1990s, the research community has been arguing for the need for a large-scale, sustained Arctic observing system. These efforts have culminated in two initiatives: (1) the U.S.-led Study of Environmental Change (SEARCH), and (2) the European Union-led Developing Arctic Modeling and Observing Capabilities for Long-Term Environmental Studies (DAMOCLES). Both programs were timed to coordinate major efforts during the International Polar Year of 2007-2008 and are at present working to leave in place long-term observing systems. The U.S. effort is spearheaded by the NSF and has led to development of the Arctic Observing Network (AON). The AON primarily provides data from NSF-sponsored investigators. The Arctic Council has organized a project known as Sustaining Arctic Observing Networks, or SAON, which offers to help coordinate sustained observations and to serve as a data portal (www.arcticobserving.org). The naval forces would benefit from being involved with these planning efforts.


FINDING 6.3: The Navy has billions of dollars in assets exposed to the threats of climate change, and it must make strategic decisions in the face of considerable uncertainty about the pace, magnitude, and regional manifestations of climate change. Yet Navy research at present has no capability for modeling the coupled ocean-atmosphere-land-cryosphere system and how it will respond to greenhouse gas forcing. The Navy also has no programs in seasonal-to-decadal timescale

29

Cecilia M. Bitz. 2008. “Some Aspects of Uncertainty in Predicting Sea Ice Thinning,” Arctic Sea Ice Decline: Observations, Projections, Mechanisms and Implications, E.T. DeWeaver, C.M. Bitz, and B. Tremblay (eds.), pp. 63-76.

30

Julien Boe, Alex Hall, and Xin Qu. 2009. “September Sea-Ice Cover in the Arctic Ocean Projected to Vanish by 2100,” Nature Geoscience, Vol. 2, pp. 341-343.

31

Cecilia M. Bitz, J.K. Ridley, M.M. Holland, and H. Cattle. 2010. “20th and 21st Century Arctic Climate in Global Climate Models,” in press in Arctic Climate Change—The ACSYS Decade and Beyond, P. Lemke (ed.).



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