The most recent, detailed picture of ice loss from Greenland is presented in a new study, published online today in Geophysical Research Letters.
A team of scientists, led by researchers from the UK Centre for Polar Observation and Modelling at the University of Leeds, combined data from the European Space Agency’s CryoSat mission with a regional climate model to map changes in Greenland ice sheet mass.
They found that between 2011 and 2014 Greenland lost around one trillion tonnes of ice. This corresponds to a 0.75 mm contribution to global sea level rise each year, around twice the average of the preceding two decades.
Credit:Planetary Visions
Importantly, CryoSat’s sophisticated radar altimeter has also allowed the researchers to map the complex regional pattern of imbalance that lies behind this headline figure.
“CryoSat‘s radar really brings into focus our view of the ice sheet, revealing which glaciers are exhibiting the greatest signs of change,” explained lead author Dr Mal McMillan. “This helps us to study Greenland’s individual outlet glaciers, which in turn allows us to better understand the contribution they have made to global sea level rise”.
The team also mapped annual changes in the ice sheet mass over the survey period. They found large variations in the amount of ice lost from year to year, with the highest losses by far occurring in the warm summer of 2012 and smaller losses in other years. These measurements highlight how sensitive Greenland’s ice is to sudden changes in its surrounding environment.
CryoSat’s measurement of Greenland ice losses are in close agreement with those computed from NASA’s GRACE gravimetry mission, which carries sensors that are specially designed to weigh changes at the scale of the entire ice sheet.
CPOM Director and principal scientific advisor to the CryoSat mission Professor Andy Shepherd summarised: “Having already delivered assessments of Antarctica and Arctic sea ice, these findings from Greenland are a major step towards completing CryoSat’s picture of how Earth’s ice is changing. As well as being able to routinely monitor polar ice sheet losses as a whole, CryoSat is a tool for pinpointing glaciers that are responding to environmental change”.
Further information:
The full reference is: McMillan, M. et al. (2016) A high resolution record of Greenland mass balance, Geophysical Research Letters 43, doi:10.1002/2016GL069666.
Dr McMillan is available for comment (m.mcmillan@leeds.ac.uk).