A Feedback, But How Large?

Zhuang and colleagues, in GRL, publish a new analysis of high-latitude carbon source/sink behavior. Their conclusion, considering among other issues CO2 fertilization and the contribution of fire to the system (see here for a discussion of the fire CO2 source/sink issue) that the region’s CO2 contributions will go up as things warm over the century, but that “these emissions will exert relatively small radiative forcing on global climate system compared to large amounts of anthropogenic emissions.”