Greenland glacier melt made worse by wildfires; may add more to sea-level rise than previously thought
The melting of Greenland's ice sheets and glaciers has been a great concern in recent years, and new research is adding even more bad news, as ice cores show a link between wildfires and ice melt, and satellite images reveal that the canyons the island's glaciers rest in are deeper and longer than previously thought, meaning that the melt will contribute more to sea-level rise than has been predicted.
Exactly how much snow and ice melts in the Arctic each year is dependent on a few different factors, but one of the most important ones is albedo - the ability to reflect the Sun's rays back into space. Snow and ice are highly reflective for sunlight, sending roughly 90 per cent of it back into space. On average, the maximum surface area of the Greenland ice sheets and glaciers that experiences some kind of melting in the summer months is around 25 per cent of the total. However, in 2012, the melting peaked at 97 per cent. Partly this was due to the weather pushing higher temperatures over the area, but as the members of the Dark Snow Project discovered, it also had to do with something else the weather brought with it - black carbon soot and industrial pollution that settled on the ice. This darkened the ice, lowering its albedo, and thus increasing the amount of sunlight that was absorbed.
The following video goes into detail about their findings, and includes a short plea for support to continue this important research for another season:
Meanwhile, a combination of data from satellites sweeping high over Greenland and from flights of NASA's Operation IceBridge over the area have been giving scientists some very precise measurements to determine the topography of the island's coastlines. This is in an effort to see exactly how much ice is resting on the island and give us an idea of how much this ice may contribute to future sea level rise. Glaciers melted by the ocean water in Greenland eventually retreat back onto bedrock that is above sea level, and once on this dry land, their melt decreases significantly. Exactly how long it takes for the glacier to melt back onto that 'dry land' determines how much it will contribute to sea level rise. Up until now, it was assumed that most of the glaciers there did not have far to melt before they lost contact with the ocean, but the results of these satellite sweeps are showing that isn't the case. For some, the canyon they rest in extend back over 100 kilometres from the coastline.
"The glaciers of Greenland are likely to retreat faster and farther inland than anticipated, and for much longer, according to this very different topography we have discovered,” said Mathieu Morlighem, a scientist with the University of California at Irvine who led the study of this satellite data, according to a NASA press release.
The depth of the canyons is adding to the problem, since it is increasing the estimates of exactly how much ice each glacier contains. Also, since many of these canyons plunge well below sea-level, the situation may develop into one similar to what's being seen in West Antarctica - where the glaciers there have passed the point of no return and since the ground underneath them is below sea level with nothing to block their movement, they will eventually completely collapse into the ocean.
This animation shows the topography of the west coast of Greenland, revealing some of the incredible canyons they've discovered: