Semi-arid regions may be key to understanding and predicting variations in the land CO2 sink

Semi-arid regions may be key to understanding and predicting variations in the land CO2 sink

Terrestrial ecosystems pull about one-fourth of anthropogenic CO2 emissions out of the atmosphere per year, serving as a sink for CO2 since industrialization. Minor swings in CO2 fluxes can cause large variations in the net carbon exchange between the land and atmosphere. This flux variability comprises the majority of interannual variations about the general trend in atmospheric CO2 concentrations. However, the role that regional ecosystems play in causing this variability is not well known.

An international research team with partial support from the CPO Modeling, Analysis, Predictions, and Projections program, recently published in Science an assessment of the contributions of regional terrestrial ecosystems to the average sink, recent trend, and interannual variability of atmospheric CO2.

The study, published in Science on May 22, applied an ensemble of ecosystem and land-surface models as well as an empirical gross primary production product to the analysis. They found that highly productive lands, especially tropical forests, heavily influence the average sink, while semi-arid ecosystems, mostly in low latitudes, strongly influence the trend and interannual variability of the atmospheric CO2 sink.

Understanding the role of these semi-arid regions could be essential for predicting interannual and longer-term variations in the land sink and global carbon cycle.

To view the paper in Science, visit:



Dr. Annarita Mariotti
MAPP Program Director
P: 301-734-1237

Dr. Daniel Barrie
MAPP Program Manager
P: 301-734-1256

Alison Stevens*
MAPP Program Specialist
P: 301-734-1218

Emily Read*
MAPP Program Assistant
P: 301-734-1257

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«July 2018»


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