Alaska’s tundra releasing more CO2 than it takes in: study

FILE PHOTO: NEWTOK, AK - JULY 06: The marshy, tundra landscape surrounding Newtok is seen from a plane on July 6, 2015 outside Newtok, Alaska. Newtok, which has a population of approximately of 375 ethnically Yupik people, was established along the shores of the Ninglick River, near where the river meets the Bering Sea, by the Bureau of Indian Affairs (BIA) in 1959. The Yupik people have lived on the coastal lands along the Bering Sea for thousands of years. However, as global temperatures rise the village is being threatened by the melting of permafrost; greater ice and snow melt - which is causing the Ninglick river to widen and erode the river bank; and larger storms that come in from the Bering Sea, which further erodes the land. According to the U.S. Army Corp of Engineers, the high point in Newtok - the school - could be underwater by 2017. A new village, approximately nine miles away titled Mertarvik, has been established, though so far families have been slow to relocate to the new village.   Andrew Burton/Getty Images/AFP
FILE PHOTO: NEWTOK, AK – JULY 06: The marshy, tundra landscape surrounding Newtok is seen from a plane on July 6, 2015 outside Newtok, Alaska. Newtok, which has a population of approximately of 375 ethnically Yupik people, was established along the shores of the Ninglick River, near where the river meets the Bering Sea, by the Bureau of Indian Affairs (BIA) in 1959. The Yupik people have lived on the coastal lands along the Bering Sea for thousands of years. However, as global temperatures rise the village is being threatened by the melting of permafrost; greater ice and snow melt – which is causing the Ninglick river to widen and erode the river bank; and larger storms that come in from the Bering Sea, which further erodes the land. According to the U.S. Army Corp of Engineers, the high point in Newtok – the school – could be underwater by 2017. A new village, approximately nine miles away titled Mertarvik, has been established, though so far families have been slow to relocate to the new village. Andrew Burton/Getty Images/AFP

WASHINGTON, United States (AFP) — The Alaskan tundra appears to be emitting more carbon dioxide than it captures, a dynamic that could accelerate climate warming as vast stores of CO2 trapped in Arctic soils are unlocked by rising temperatures.

A question scientists have had is whether a warming climate would lead to a greater intake of CO2 through photosynthesis during the summer growing season.

But a study published Monday in the Proceedings of the National Academy of Sciences found that in Alaska’s North Slope any increase in the uptake of CO2 was more than offset by especially high rates of CO2 “respiration” during early winter.

Data gathered by the National Oceanographic and Atmospheric Administration showed a 73 percent in carbon emissions between 1975 and 2015 during that October to December period, according to the study led by Roisin Commane of Harvard University.

“We present the first quantitative evidence for large, regional-scale early winter respiration flux, which more than offsets carbon uptake in summer in the Arctic,” the researchers said.

Their findings support the view that “rising temperatures have made Arctic ecosystems a net source of CO2,” they said.

A question it raises is to what extent increase in emissions is from the decomposition of ancient vegetation trapped for decades or even centuries in the permafrost, and now being exposed to the atmosphere.

The researchers estimate that the Arctic permafrost contains more CO2 than the Earth’s atmosphere.

Forty years ago, the ground in Alaska froze completely in less than a month in autumn, whereas it now may take three months to freeze in some places.

The Arctic is warming at twice the rate as the rest of the planet, and Alaska has seen three consecutive years of record high temperatures, the scientists noted.

In 2016, the planet’s hottest since records were first kept in 1880, the temperature was 3.27 degrees Celsius above the historic average.

© Agence France-Presse