Sea level could rise by 0.6–1.6 metres by 2100, according to a new analysis.
In its 2007 assessment report, the Intergovernmental Panel on Climate Change estimated that thermal expansion of the ocean and ice melt alone could raise sea level by 18–59 centimetres this century.
Rather than projecting individual components of sea level rise separately, Svetlana Jevrejeva of the Proudman Oceanographic Laboratory, UK, and colleagues used a statistical model to estimate the cumulative impact of a variety of warming and cooling agents — both natural and man-made — on twenty-first-century sea level rise.
They also looked at the relative importance of factors contributing to future sea level rise and found that higher concentrations of atmospheric carbon dioxide would be responsible for the majority of the increase. Even if solar radiation were to reach its lowest level in the past 9,300 years, it would reduce potential sea level rise by only 10–20 centimetres. And if volcanic activity reached its highest level in the past 1,000 years, twenty-first-century sea level rise would be just 10–15 centimetres less.
The researchers say their estimates are in line with past sea level responses to temperature change, and they suggest that estimates based on ice and ocean thermal responses alone may be misleading.