Warmer weather causing Alaska's tundra to release more CO2

New York

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.

Will Arctic and near-Arctic regions continue to take more carbon dioxide from the atmosphere through plant activity than they release, or will they release more than they store?

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 conti…