ESA- und NASA-Satelliten liefern erstes gemeinsames Bild vom Abschmelzen des grönländischen Eisschildes. Zwischen 2010 und 2023 ist der grönländische Eisschild durchschnittlich um 1,2 Meter dünner geworden. Allerdings war die Ausdünnung am Rand des Eisschildes (der Ablationszone) mehr als fünfmal größer und betrug durchschnittlich 6,4 Meter.

Academics from Northumbria University are part of an international research team which has used data from satellites to track changes in the thickness of the Greenland Ice Sheet.

Global warming is causing the Ice Sheet to melt and flow more rapidly, raising sea levels and disturbing weather patterns across our planet.

Because of this, precise measurements of its changing shape are of critical importance for tracking and adapting to the effects of climate warming.

Scientists have now delivered the first measurements of Greenland Ice Sheet thickness change using CryoSat-2 and ICESat-2 – the ESA and NASA ice satellite missions.

Both satellites carry altimeters as their primary sensor, but they make use of different technologies to collect their measurements.

CryoSat-2 carries a radar system to determine the Earth’s surface height, while ICESat-2 has a laser system for the same task.

Although radar signals can pass through clouds, they also penetrate into the ice sheet surface and have to be adjusted for this effect.

Laser signals, on the other hand, reflect from the actual surface, but they cannot operate when clouds are present.

The missions are therefore highly complementary, and combining their measurements has been a holy grail for polar science.

A new study from scientists at the UK Centre for Polar Observation and Modelling (CPOM), based at Northumbria University, and published in Geophysical Research Letters shows that CryoSat-2 and ICESat-2 measurements of Greenland Ice Sheet elevation change agree to within 3%.

This confirms that the satellites can be combined to produce a more reliable estimate of ice loss than either could achieve alone. It also means that if one mission were to fail, the other could be relied upon to maintain our record of polar ice change.

Between 2010 and 2023, the Greenland Ice Sheet thinned by 1.2 metres on average. However, thinning across the ice sheet’s margin (the ablation zone) was over five times larger, amounting to 6.4 metres on average.

The most extreme thinning occurred at the ice sheets outlet glaciers, many of which are speeding up.

At Sermeq Kujalleq in west central Greenland (also known as Jakobshavn Isbræ), peak thinning was 67 metres, and at Zachariae Isstrøm in the northeast peak thinning was 75 metres.

Altogether, the ice sheet shrank by 2,347 cubic kilometres across the 13-year survey period – enough to fill Africa’s Lake Victoria.

[https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2024GL110822](https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2024GL110822)