Rising Sea Levels: A Watery
Fate for Airports — December 2021

Sea levels are rising because of global warming. The global mean sea level (GMSL) during the 20th Century rose by an estimated 1.4mm a year. In the decade up to 2015 its rate of increase had increased to 3.6mm a year and since then accelerated to 4.6mm a year. It doesn’t sound much: but as the chart shows this works out at a metre since 1993.

The Arctic sea ice extent, according to NSDC and NASA, has fallen significantly in all months since satellite measurements started in 1979, and the current level of decline is running at 13% a decade (relative to the 1981-2010 average). The Antarctic ice sheet is losing 152 gigatonnes of mass each year, while the Greenland ice sheet is declining at an annual rate of 267Gt. Since 2002 between them the ice sheets have lost a total of 7,700Gt of mass. That’s a lot of water.