Forest Response to Rising CO2 Drives Zonally Asymmetric Rainfall Change Over Tropical Land

TitleForest Response to Rising CO2 Drives Zonally Asymmetric Rainfall Change Over Tropical Land
Publication TypeJournal Article
Year of Publication2018
JournalNature Climate Change
Volume8
Number5
Pages434-440
Date Published04/2018
Abstract / Summary

Understanding how anthropogenic CO2 emissions will influence future precipitation is critical for sustainably managing ecosystems, particularly for drought-sensitive tropical forests. Although tropical precipitation change remains uncertain, nearly all models from the Coupled Model Intercomparison Project Phase 5 predict a strengthening zonal precipitation asymmetry by 2100, with relative increases over Asian and African tropical forests and decreases over South American forests. Here we show that the plant physiological response to increasing CO2 is a primary mechanism responsible for this pattern. Applying a simulation design in the Community Earth System Model in which CO2 increases are isolated over individual continents, we demonstrate that different circulation, moisture, and stability changes arise over each continent due to declines in stomatal conductance and transpiration. The sum of local atmospheric responses over individual continents explains the pan-tropical precipitation asymmetry. Our analysis suggests that South American forests may be more vulnerable to rising CO2 than Asian or African forests.

URLhttp://dx.doi.org/10.1038/s41558-018-0144-7
DOI10.1038/s41558-018-0144-7
Journal: Nature Climate Change
Year of Publication: 2018
Volume: 8
Number: 5
Pages: 434-440
Date Published: 04/2018

Understanding how anthropogenic CO2 emissions will influence future precipitation is critical for sustainably managing ecosystems, particularly for drought-sensitive tropical forests. Although tropical precipitation change remains uncertain, nearly all models from the Coupled Model Intercomparison Project Phase 5 predict a strengthening zonal precipitation asymmetry by 2100, with relative increases over Asian and African tropical forests and decreases over South American forests. Here we show that the plant physiological response to increasing CO2 is a primary mechanism responsible for this pattern. Applying a simulation design in the Community Earth System Model in which CO2 increases are isolated over individual continents, we demonstrate that different circulation, moisture, and stability changes arise over each continent due to declines in stomatal conductance and transpiration. The sum of local atmospheric responses over individual continents explains the pan-tropical precipitation asymmetry. Our analysis suggests that South American forests may be more vulnerable to rising CO2 than Asian or African forests.

DOI: 10.1038/s41558-018-0144-7
Citation:
Kooperman, GJ, Y Chen, FM Hoffman, CD Koven, K Lindsay, M Pritchard, AL Swann, and J Randerson.  2018.  "Forest Response to Rising CO2 Drives Zonally Asymmetric Rainfall Change Over Tropical Land."  Nature Climate Change 8(5): 434-440.  https://doi.org/10.1038/s41558-018-0144-7.