During spring and summer, as the air warms up and the sun shines down on the Greenland Ice Sheet, melt ponds form. Melt ponds are extensive pools of open water that form on both sea ice and ice sheets and are visible from space.
When snow and ice melt on top of glaciers, water flows in channels and streams and collects in depressions on the surface. These melt ponds can speed up the melting of the surrounding ice since they significantly reduce the ice’s ability to reflect sunlight. This can initiate a positive feedback where an increasing number of melt ponds absorb more heat which causes ice cover to melt even faster.
The Greenland Ice Sheet is the greatest ice mass in the northern hemisphere. It extends 2220 km north-south and has an average thickness of around 1500 m and is 1100 km at its widest point.
The first day of September usually marks the end of the Greenland melt season, as the sun moves lower in the sky with temperatures cooling. However, at the beginning of September 2022, temperatures began to rise again when a strong air pressure region stalled at the southeast edge of Greenland and drew warmer air northwards across Baffin Bay and the west coast of Greenland. This increased meltwater runoff into the ocean.
Earth observation satellites are key to monitoring ice as they measure changes in the thickness of the ice sheets, fluctuations in the speed of the outlet glaciers and even small changes in Earth’s gravity field caused by melting ice as well as sea-level rise.