A large carbon sink in the woody biomass of Northern forests

TLDR

The terrestrial carbon sink, as yet unidentified, accounts for 15–30 % of annual global fossil‑fuel emissions, and missing carbon is sequestered in vegetation biomass that can be used under the Kyoto Protocol to meet emissions‑reduction commitments. The study analyzes 19 years of remote‑sensing and inventory data to identify the size and location of forest biomass sinks. We used high‑resolution remote‑sensing and inventory data over 19 years to estimate biomass carbon changes, enabling ground validation and supporting Kyoto‑protocol monitoring. Between 1981 and 1999, Eurasian boreal and North American temperate forests gained biomass carbon while some Canadian boreal forests lost it, and the 1.42 billion‑hectare Northern forest region above the 30th parallel sequestered an estimated 0.68 ± 0.34 billion tons of carbon per year, about 70 % of which is in Eurasia.

Abstract

The terrestrial carbon sink, as of yet unidentified, represents 15–30% of annual global emissions of carbon from fossil fuels and industrial activities. Some of the missing carbon is sequestered in vegetation biomass and, under the Kyoto Protocol of the United Nations Framework Convention on Climate Change, industrialized nations can use certain forest biomass sinks to meet their greenhouse gas emissions reduction commitments. Therefore, we analyzed 19 years of data from remote-sensing spacecraft and forest inventories to identify the size and location of such sinks. The results, which cover the years 1981–1999, reveal a picture of biomass carbon gains in Eurasian boreal and North American temperate forests and losses in some Canadian boreal forests. For the 1.42 billion hectares of Northern forests, roughly above the 30th parallel, we estimate the biomass sink to be 0.68 ± 0.34 billion tons carbon per year, of which nearly 70% is in Eurasia, in proportion to its forest area and in disproportion to its biomass carbon pool. The relatively high spatial resolution of these estimates permits direct validation with ground data and contributes to a monitoring program of forest biomass sinks under the Kyoto protocol.