Tundra May Be Shifting Alaska to Put Out More Carbon Than It Stores, Study Says
https://www.nytimes.com/2017/05/08/climate/alaska-carbon-dioxide-co2-tundra.html
Source: By Henry Fountain, The New York Times
For Investigation: 10.3
Excerpt: As global warming continues, a big unknown is what will happen to the carbon balance between the atmosphere and the land, especially in the far north. ...A new study suggests that Alaska, with its huge stretches of tundra and forest, may be shifting from a net sink, or storehouse, of carbon to a net source. The study focused on one possible cause: warmer temperatures that keep the Arctic tundra from freezing until later in the fall, allowing plant respiration and microbial decomposition — processes that release carbon dioxide — to continue longer. Roisin Commane, a researcher at Harvard, and others studied atmospheric carbon dioxide in the state, using measurements from aircraft and a 40-year record from sensors operated by the National Oceanic and Atmospheric Administration in Barrow, in the North Slope Borough. They found that carbon emissions from the North Slope tundra in October, November and December had increased by 70 percent since the 1970s. “We were surprised by the magnitude of CO2 coming out in the fall,” Dr. Commane said. ...Climate change is having more of an impact in high northern latitudes than in other areas. Warming is occurring about twice as fast in the Arctic as elsewhere, and sea ice in the Arctic Ocean has been declining by about 13 percent per decade since the 1980s. Last fall, the region experienced several bouts of unusual weather, with mean temperatures at the North Pole in November more than 20 degrees above normal....
Source: By Henry Fountain, The New York Times
For Investigation: 10.3
Excerpt: As global warming continues, a big unknown is what will happen to the carbon balance between the atmosphere and the land, especially in the far north. ...A new study suggests that Alaska, with its huge stretches of tundra and forest, may be shifting from a net sink, or storehouse, of carbon to a net source. The study focused on one possible cause: warmer temperatures that keep the Arctic tundra from freezing until later in the fall, allowing plant respiration and microbial decomposition — processes that release carbon dioxide — to continue longer. Roisin Commane, a researcher at Harvard, and others studied atmospheric carbon dioxide in the state, using measurements from aircraft and a 40-year record from sensors operated by the National Oceanic and Atmospheric Administration in Barrow, in the North Slope Borough. They found that carbon emissions from the North Slope tundra in October, November and December had increased by 70 percent since the 1970s. “We were surprised by the magnitude of CO2 coming out in the fall,” Dr. Commane said. ...Climate change is having more of an impact in high northern latitudes than in other areas. Warming is occurring about twice as fast in the Arctic as elsewhere, and sea ice in the Arctic Ocean has been declining by about 13 percent per decade since the 1980s. Last fall, the region experienced several bouts of unusual weather, with mean temperatures at the North Pole in November more than 20 degrees above normal....