What does the paleoclimate record tell us about the status of the Greenland Ice Sheet?
The range and variability of past climate fluctuations are consistent with modern records, but they appear to be imposed on a general long-term warming trend that is evident in both historical (the past 120 years) and paleoclimate records. Continued warming will have widespread impacts on all aspects of the Arctic system, some with global consequences. More than 85 percent of the Arctic landscape is underlain by permanently frozen ground (permafrost) that is vulnerable to warming. Permafrost thaw induces landscape instability which impacts infrastructure, rivers, and ecosystems. Thawing of permafrost will increase the decomposition of widespread high-latitude peatlands, significantly increasing the rate of CO2 and methane release to the atmosphere from these areas. Injections of methane could also come from breakdown of clathrates (frozen gas hydrates) known to be widespread beneath the Arctic continental shelves. These changes will have global consequences, increasing greenhouse gas l
