Warming, thawing and decrease in areal extent of terrain underlain by permafrost are expected in response to climatic change in the 21st century (Sazonova et al., 2004; Euskirchen et al., 2006; Lemke et al., 2007). (ipcc.ch)
Rover, J., L. Ji, B. K. Wylie, and L. L. Tieszen, 2012: Establishing water body areal extent trends in interior Alaska from multi-temporal Landsat data. (nca2014.globalchange.gov)
They also used pond data collected during the International Biological Program in the 1970s, including areal extent estimates, water depths, and pond depths, and compared those with field data collected from 2011 to 2013. (sciencemag.org)