Sea level rise over the next 2000 years

A new paper by Levermann et al. in PNAS uses the record of past rates of sea level rise from palaeo archives and numerical computer models to understand how much sea level rise we can expect per degree of warming in the future. These data suggest that we can expect a global sea level rise of 2.3 m per 1°C of warming within the next 2000 years: well within societal timeframes. A 2°C of warming would result in a global sea level rise of 4.8 m within 2000 years. This would inundate many coastal cities in Europe alone, and cause untold economic and societal damage.

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Arctic Sea Ice

The Arctic’s sea ice extent reached an all-time low in September 2012, with the smallest recorded extent since satellite observations began. At 3.42 million square kilometres, it may still sound large, but this small extent of Arctic sea ice could have profound long-term consequences, and it follows a long trend of low sea ice conditions. Sea ice extent has been decreasing over the past 4-5 decades (Kinnard et al., 2011), and sea ice extent is now about 2 million square kilometres less than it was during the late twentieth century. Continue reading