Dynamics of carbon storage in the woody biomass of northern forests

Part of the puzzle of greenhouse gases and climate change is determining where carbon dioxide (CO₂) is absorbed, and what causes a region to become a “carbon sink”. Analyses of atmospheric CO₂ concentration changes indicate a carbon sink of about 1 to 2 billion tons on land in the northerly regions. Elsewhere the land is suggested to be neutral, which implies that emissions of another 1.5 billion tons of carbon a year from cutting and burning of tropical forests are nearly balanced by sinks of similar magnitude there. The geographical detail of the land carbon sink has, however, remained elusive.; Forest greenness observations from sensors on National Oceanic and Atmospheric Administration satellites were combined with wood volume data from forest inventories to produce relatively high resolution maps of carbon stocks in about 15 million square kilometers of northern forests, roughly above the 30th parallel. Comparison of carbon stock maps from the late 1990s and early 1980s identifies where forests were storing carbon and where they were losing carbon. Results indicate that about 61 billion tons of carbon is contained in the wood of these northern forests.; Further, the analysis indicates that forests in Europe, Russia and America have been storing nearly 700 million metric tons of carbon a year, or about 12% of annual global carbon emissions from industrial activities, during the 1980s and 1990s. American forests absorbed 120 million tons of carbon a year, which is about 11% of the USA's annual emissions. With the exception of some Canadian boreal forests, which were found to be losing carbon, most northern forests were storing carbon. Russia, the country with the most forests, accounted for almost 40 percent of the biomass carbon sink.; This study has important scientific, economic and policy implications. The scientific implication is that it deconstructs the mystery of the land carbon sink by providing geographically detailed maps of forest carbon pools, sources and sinks. The economic implication is that the wood volume maps provide valuable information to the forest industry. This study also has political relevance as a potential tool for monitoring carbon sequestration in the future.