Saving the Greenland ice sheet
Press release issued: 15 December 2009
Climate geoengineering may help maintain the Greenland ice sheet by reducing the amount of sunlight that reaches the Earth’s surface which in turn would cool the climate, despite rising CO2 levels.
Pete Irvine, lead author on the paper, said: “Climate geoengineering could be an emergency response if dangerous melting of the Greenland ice sheet begins, or other climate emergencies occur, but it is no substitute for reductions in the emission of CO2.”
It is predicted that in a future with high levels of atmospheric CO2 the Greenland ice sheet would eventually melt. Using climate models, researchers from the University of Bristol calculated what might happen if in-coming solar radiation were reduced in a future where CO2 is roughly three times higher than it is today.
The sunlight could be deflected either by creating a ‘sunshade’ consisting of a huge array of reflective satellites between the Earth and the Sun, or by injecting sulphate aerosols into the stratosphere.
Reporting in Environmental Research Letters the team found that if a small fraction, 4.2%, of the sunlight that reaches Earth were deflected then the much warmer, high CO2 world could be cooled enough to return the Earth’s average temperature to pre-industrial levels. This geoengineered climate would be cool enough to prevent the Greenland ice sheet from melting.
However, the team found that although such schemes could cool the climate, they would also make it drier and change weather patterns. Reflecting only 2.5% of solar radiation could reduce these undesired changes and still help prevent collapse of the Greenland ice sheet.