2012, a record year

Since the end of the 1990’s (and in particular since 2007), the Greenland ice sheet has been continuously losing mass. There are two main reasons for this: the increase of the surface melt and in discharge of icebergs into the ocean. In 2012, the absolute melt maximum in fifty years was reached (more than 100 % melt in respect to the average). Mid-July 2012, the whole surface of the ice sheet was melting. “The 2012 melt largely exceed all previous records. The ice sheet is really melting in a significant way”, explains Xavier Fettweis, FNRS postdoctoral researcher at the Laboratory of Climatology and Topoclimatology of the University of Liege.

This is explained not only by the global warming but a change in summertime atmospheric gneral circulation abover Greenland. For ten years, a occurence increase of anticyclones centred on the South of Greenland has been observed. Favoring winds from the South, these anticyclones bring warm air to the West coast of Greenland and accelerate the process of surface melt.

While the ice sheet had always managed to keep in balance between its gains and losses, the record melts of recent years have led to fear of a reversal of the situation. In the month of August 2012, Greenland’s surface mass balance of reached the absolute minimum recorded for at least 50 years. The ice sheet was therefore no longer balanced with the surface melt and detachment of icebergs exceeding snowfall. The atmospheric conditions of the next few months will be determining factors for the balance in 2012. If the direction wind does not change and melt continues to occur, the 2012 mass balance could finish in deficit and the gain/loss balance could be broken.

What are the consequences for the climate?

The island of ice is attracting researchers from all over the world due to its consequences for the environment. A melt of the Greenland ice sheet will have an impact on our climate.

Even partial melt of the ice causes an irreversible increase in sea levels, with the meltwater from the ice sheet flowing into the Atlantic Ocean. Currently the losses in mass of the Greenland ice sheet correspond to an increase in sea levels of nearly 1 to 2 mm by year. The meltwater flow from Greenland could cause an increase of the sea level of around 5 to 20 cm by 2100, representing a danger to certain coastal countries situated at low altitude such as the Netherlands. In addition to this, the possible accelartion of icebergs discharge into the ocean will contribute to further losses in mass of up to 20-30 %.