每日跟讀#670: Arctic wildfires spew soot and smoke cloud bigger than EU
A cloud of smoke and soot bigger than the EU is billowing across Siberia as wildfires in the Arctic Circle rage into an unprecedented third month. The normally frozen region, which is a crucial part of the planet’s cooling system, is spewing carbon dioxide into the atmosphere and worsening the manmade climate disruption that created the tinderbox conditions.
A spate of huge fires in northern Russia, Alaska, Greenland and Canada discharged 50 megatonnes of CO2 in June and 79 megatonnes in July, far exceeding the previous record for the Arctic. The intensity of the blazes continues with 25 megatonnes in the first 11 days of August — extending the duration beyond even the most persistent fires in the 17-year dataset of Europe’s satellite monitoring system.
Mark Parrington, a scientist in the Copernicus Atmosphere Monitoring Service, said the previous record was just a few weeks. “We haven’t seen this before,” he said. “The fire intensity is still well above average.” He said the affected regions previously registered unusually high temperatures and a low level of soil moisture, which created the perfect conditions for ignition. Globally, June and July were the hottest months ever measured.
The Earth observation scientist Josef Aschbacher said that in Siberia alone, the two-month inferno had destroyed 4.3 million hectares of taiga forest. The smoke has spread further still. Antti Lipponen, of the Finnish Meteorological Institute, estimates the affected area at 5 million square kilometers. “For comparison, the area of EU is about 4.5 million square kilometers and the area of contiguous US about 8.1 million square kilometers,” he tweeted.
The cloud is billowing northeast and is forecast to reach Alaska, where this year’s fires have already scorched an area bigger than all the wildfires that devastated California last year. Carly Phillips, of the Union of Concerned Scientists, said Alaskan fires had burned 7.32 million hectares of forest since 2000, more than double the amount over the previous 20 years.
“Carbon emissions from these wildfires could exacerbate climate warming for decades to come,” she wrote in a blogpost. “Alaska’s ecosystems store huge quantities of carbon both as permafrost and soil that has accumulated over millennia. Wildfires destabilize these stores of carbon by combusting soil and accelerating permafrost thaw, both of which release heat-trapping gases to the atmosphere.”
The black soot also settles on what is left of the Arctic ice, weakening its ability to reflect the heat of the sun. In Greenland, satellite images this month revealed fires stretching across an area 380km wide, adding to the pressures of an Arctic heatwave that caused a record melt-off of the world’s second biggest ice sheet.
Since the start of the year, more than 13.1 million hectares have burned, according to Greenpeace, which says this has released as much carbon dioxide as a year’s worth of exhaust fumes from 36 million cars. The Arctic is not the only afflicted region. So far this year, the EU has had 1,600 fires bigger than 30 hectares, which is four times the annual average over the previous decade, according to the Copernicus Atmosphere Monitoring Service.
Source article: http://www.taipeitimes.com/News/lang/archives/2019/08/25/2003721057/2