Melting ice in Greenland and Antarctica is now the main cause of the global rise in sea level, French scientists report in the journal Global and Planetary Change – a new climate tipping point has been reached.
Until now, the overwhelming cause of sea-level rise has been the result of oceans expanding as they get hotter with global warming. The oceans will continue to expand, but now glacial melt has overtaken expansion as the leading contributor to ocean volume. Greenland alone contains enough frozen water to raise sea levels by 7 metres.
Melting of sea ice in the Arctic (and Antarctica) doesn’t directly affect sea-level because the ice is already in the water and, like melting ice cubes in a glass of water, there is no overall change to the liquid volume. All ice-melt has an indirect effect on climate change, however, because it reduces the Earth’s ability to reflect the Sun’s rays (its albedo). This in turn heats the remaining ice, exaccerbating melting, and warming…