Drought Weakens Carbon Sink in Western North America
The 2000-2004 drought in western North America was the worst drought in the past 800 years, according to a new study in Nature Geoscience. Western North America is currently a carbon sink—a reservoir, such as oceans or plants, that absorbs carbon dioxide. The authors found that the recent drought resulted in less carbon uptake, as well as a reduction in river discharge and reduced cropland productivity. After comparing their findings to past climate in the region, they determined that the last drought of equal magnitude was over 800 years ago. With the frequency and severity of climatic extremes, including drought, projected to increase due to climate change, the authors warn that the carbon sink in western North America could disappear by the end of the century.
Authors of another study in Nature also observed carbon sinks, this time on a global scale. They found that global carbon uptake doubled between 1960 and 2010, taking in about 55 percent of the carbon emitted by humans during that time. If the land and oceans weren’t taking up as much carbon as they have been over the last 50 years, the Earth would have warmed much more than it has, according to the authors.