Research press release


Nature Climate Change

Millions of Americans at risk from rising seas



今回、Mathew Hauerたちは、さまざまな海抜と洪水リスクと米国の沿岸各州の小規模な人口予測を考慮に入れた地域特異的な環境データと米国海洋大気庁(NOAA)の海水準上昇予測を組み合わせて、この難問に取り組んだ。その結果、2100年に海水準が0.9メートル上昇するというシナリオでは、米国の沿岸地域の住民420万人が洪水の危険にさらされることが判明した。また、NOAA予測で最悪レベルの1.8メートルの海水準上昇では、1310万人が洪水の危険にさらされることも分かった。その約半数がフロリダ州の住民であり、約70%は米国南東部の住民で占められている。

Sea-level rise could put as many as 13.1 million people along the coast of the United States at risk of flooding in the future, reports a new paper published online this week in Nature Climate Change. The study, which accounts for the rapid population growth in coastal areas, suggests that the risk is three times larger than indicated by current populations. Large numbers of people may need to relocate if protective measures are not taken, with projected movements of a magnitude similar to the twentieth-century Great Migration of southern African-Americans.

Sea-level rise is one of the most obvious threats to society as a result of climate change. However, the degree to which sea levels will rise is uncertain, and predicting flood patterns can be difficult due to local geographical variations and uncertainties around future population changes. Previous studies have therefore struggled to quantify the number of people at risk from future sea-level rise.

Mathew Hauer and colleagues address this problem by combining location-specific environmental data, which account for different elevations and flood risks, and small-scale population projections for US coastal states with sea-level rise projections from the National Oceanic and Atmospheric Administration (NOAA). They find that a sea-level rise scenario of 0.9 metres by 2100 will put 4.2 million people in US coastal regions at risk of flooding. If sea levels rise by 1.8 metres, which represents the upper end of NOAA’s projections, that figure will rise to 13.1 million. Florida accounts for nearly half of the total at-risk population, with the southeastern US accounting for nearly 70%.

doi: 10.1038/nclimate2961


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