Until recently, scientists were uncertain about how much and where in the world terrestrial carbon is being stored. However, this month, In an issue of Science Express, scientists report that forests, including endangered rainforests, account for almost all of the world’s land-based carbon uptake.
“Our results imply that clearly, forests play a critical role in Earth’s terrestrial carbon balance, and exert considerable control over the evolution of atmospheric carbon dioxide,” said A. David McGuire, co-author and professor of ecology at the University of Alaska Fairbanks Institute of Arctic Biology and co-leader of the USGS Alaska Cooperative Fish and Wildlife Research Unit.
Even boreal forests – the subarctic evergreen coniferous forests of the northern hemisphere (dominated by firs and spruces) – are estimated to be responsible for 22 percent of the carbon stored in the world’s forests.
The report includes comprehensive estimates of carbon for the world’s forests based on recent inventory data. The scientists included information on changes in carbon pools from dead wood, harvested wood products, living plants and plant litter, and soils to estimate changes in carbon across countries, regions and continents that represent boreal, temperate and tropical forests.
The terrestrial carbon sink has been large in recent decades, but its size and location has been uncertain. Using forest inventory data and long-term ecosystem studies, this report estimated a total forest carbon sink of 2.4 gigatons a year globally between 1990 and 2007. To give some idea of the scale of the global forest carbon sink, 1 gigaton is sometimes defined as the explosive force of one billion tons of TNT.
The authors of this report suggest that understanding the present and future role of forests in the sequestration and emission of carbon is essential for informed discussions on limiting greenhouse gases. However, they also note that a warming climate has the potential to increase fires and insect damage in the boreal forest and reduce its capacity to sequester carbon.