Slow-freezing Alaska soil driving surge in carbon dioxide emissions

[Eugene]

Source: The Guardian

Slow-freezing Alaska soil driving surge in carbon dioxide emissions

Northern tundra’s autumn carbon dioxide emissions increased
70% between 1975 and 2015, researchers find, blaming warming
temperatures

Oliver Milman
Monday 8 May 2017 20.00 BST

Alaska’s soils are taking far longer to freeze over as winter approaches than in previous decades, resulting in a surge in carbon dioxide emissions that could portend a much faster rate of global warming than scientists had previously estimated, according to new research.

Measurements of carbon dioxide levels taken from aircraft, satellites and on the ground show that the amount of CO2 emitted from Alaska’s frigid northern tundra increased by 70% between 1975 and 2015, in the period between October and December each year.

Researchers said warming temperatures and thawing soils were the likely cause of the increase in CO2 at a time of year when the upper layers of soil usually start freezing over as winter sets in.

In the Arctic summer, the upper level of soil, which sits above a vast sheet of permafrost that covers much of Alaska, thaws out and decomposing organic matter starts to produce CO2. From October, colder temperatures help freeze the soil again, locking up the CO2.

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Read more: https://www.theguardian.com/us-news/2017/may/08/alaska-climate-change-tundra-soil-carbon-dioxide

[mahatmakanejeeves]

1. Alaska has long been a net absorber of CO2. That could be changing,...

Alaska has long been a net absorber of CO2. That could be changing, and if so, could contribute to faster warming.

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