Greenland lost 11 billion tons of ice in one day. How does that melt compare to the past?
Original article published by PBS News Hour
Greenland has been in the news a bit lately. From Huskies seemingly walking on water, to temperatures soaring to 20℃ above average for the time of year, to predictions of the vast ice sheet being lost entirely, what is going on?
At its most simple: ice melts when it gets too warm.
Of course, some ice melts every time summer rolls around, but the amount of Arctic ice that melts each summer is growing, and we’re waiting to see whether this turns out to be a record-breaking year for Greenland ice melt.
No part of the planet is free from the impacts of human-caused climate change. But Greenland, and the Arctic more generally, is experiencing the impacts particularly severely. Temperatures in the planet’s extreme north are rising twice as fast as the global average.
Greenland is warming so rapidly because of what climate scientists refer to as a “positive feedback”. Despite the name, these are not good. A better term might be “climate change amplifier”.
The Arctic has many “positive feedbacks” or “amplifiers” that worsen the effects of climate change here. For example, as snow and ice begin to melt, the surface darkens, allowing it to absorb more heat and thus melt even more.
This effect is most dramatic when snow and ice are lost completely, as in the case of the dramatic loss of the sea ice covering the Arctic ocean. Arctic sea ice loss is one of the major factors that explains why the Arctic is warming so much faster than the rest of the planet.
Another worrisome characteristic of climate change in the Arctic is the potential for ice melt to accelerate. The temperature threshold at which ice begins to melt means that once the climate has warmed enough to start melting ice, any further warming will rapidly cause an even larger amount of melting to occur. That is the reality beginning to play out in Greenland.