(Bloomberg) -- Strong winds carried extreme heat from the western US, Canada and the Atlantic ocean over Greenland in September, bringing average temperatures more than 8 degrees Celsius above the 30-year average and causing record ice melt.
Almost all of Greenland experienced the highest average temperatures in any month of September since records started in 1979, according to a monthly report by Europe’s Earth observation agency Copernicus. A different set of data by the US National Snow and Ice Data Center detected temperatures above 0C at Summit Station — over 3,200 meters (10,500 feet) above sea level — for the first time in September since measurements began in 1989.
The heat wave resulted in an unprecedented melt event for this time of the year that peaked between Sept. 2 and 5, according to the NSIDC. On Sept. 3, surface melting was happening on more than a third of the ice sheet, which stretches across about 600,000 square kilometers (232,000 square miles), an area equivalent to California and Nebraska combined.
In the past, most extraordinary melt events happened in July, at the height of Greenland’s melt season. But this year’s took place during what’s traditionally the end of the season. The amount of water entering the ocean on Sept. 3 was the highest for any day this season, and one of the 10 highest since 1950, according to the NSIDC. About 15.6 billion tons of Greenland surface water entered the ocean between Sept. 2 and 3.
Ice loss from the Greenland ice sheet is one of the largest contributors to rising sea levels globally. The melting has accelerated in recent decades and would continue even if the burning of fossil fuels that generates planet-warming gas emissions halted overnight, according to a paper published in August in Nature Climate Change. Using a combination of satellite observations and climate models, scientists concluded that Greenland ice melting will lead to a minimum sea rise of 27 centimeters (10.6 inches), regardless of future climate warming scenarios.
The heat that melted so much ice in Greenland was also responsible for driving unusual drought around the Northern Hemisphere. Climate change made drought this summer roughly 20 times more likely in root-zone soil north of the tropics, according to World Weather Attribution, a scientific research group. High heat and insufficient rainfall led China to release its first-ever nationwide drought warning and raised food prices there. It caused rivers to dry up around the hemisphere, and caused particular harm in Western Europe, where summer crop yields plummeted.
Globally, this was the joint fourth-warmest September for the past three decades, together with 2016, according to Copernicus. Temperatures were about 0.3C above the 1991-2020 period.
(Additional details on new research in sixth paragraph)
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