Indications of positive feedback in climate change due to a reduction in Northern Hemisphere biomass uptake of atmospheric carbon dioxide

Abstract

Mauna Loa Observatory data for atmospheric carbon dioxide (CO2) reveal, within each calendar year, a regular seasonal fluctuation: in summer, a drop in concentration occurs as the Northern Hemisphere drives uptake of CO2 into biomass, whereas in autumn/winter an increase in CO2 occurs as the Northern Hemisphere releases it through biodegradation. Analysis of the magnitude of this drop allows an estimate to be made of the biomass activity each year in the Northern Hemisphere. There are indications of a small decline in such activity since around 2006. This has potentially serious climate change implications as it may be evidence of positive feedback.