Semiarid lands and global carbon uptake
New research co-written by Steve Running, University of Montana Regents Professor of Ecology, highlights the importance of semiarid ecosystems in a recent, record-breaking uptake of atmospheric carbon dioxide.
These new findings suggest the record jump in carbon uptake in 2011 was due to enhanced vegetation growth in Australia, South America and South Africa following La Nina-driven increases in rainfall. The global plant production dataset produced by NASA satellites using Running’s software detected these trends.
Land and ocean carbon sinks absorb around half the fossil fuel emissions produced each year, slowing the rise of atmospheric CO2. Previous studies have pointed to tropical biomes as the primary land-based carbon sinks. This new research shows that dryland ecosystems also play an important role in carbon cycle dynamics.
Running and lead author Benjamin Poulter, a new faculty member at Montana State University, said that rapid vegetation growth after increased La Nina rainfall was concentrated in arid lands that typically are water-stressed.
“This study shows that although arid ecosystems like Montana don’t grow very fast, they are an important part of the global carbon balance and their response to climate trends are noticeable,” Running said. “These biomes occupy a huge area globally – some 17 million square miles – which is about 45 percent of the Earth’s land surface.”
The emerging role of semiarid ecosystems on interannual global carbon budget dynamics is unexpected, but likely only a short-term departure in long-term global trends of rising CO2 emissions.
The journal Nature published the research May 21 in an article titled “Contribution of semiarid ecosystems to interannual variability of the global carbon cycle.”
Poulter and Running are part of the Montana University System’s Institute on Ecosystems, funded by the National Science Foundation’s Experimental Program to Stimulate Competitive Research.
“It is exciting to have authors from both MSU and UM on this prominent paper in Nature magazine,” Running said.