Publication in "Science" by Matthias Forkel: "Increased boreal plant growth has enhanced yearly atmospheric CO2 fluctuations"
Carbon dioxide (CO2) concentrations in the atmosphere fluctuate with seasons: As vegetation grows in the spring and summer, it absorbs CO2, and when trees shed their leaves in the autumn, some of that gas returns to the atmosphere. The seasonal variation of CO2 has been increasing in the northern latitudes since the 1960s but the underlying mechanisms were not yet fully understood. Now, EOWAVE team member Matthias Forkel has shown in an article in “Science” (published online 21 January 2016) that increased plant growth in northern ecosystems is the main cause behind the observed increase in seasonal amplitude of atmospheric CO2.
Matthias Forkel and his former colleagues at the Max Planck Institute for Biogeochemistry were able to identify the drivers of increasing seasonal variability in CO2 by using an improved global ecosystem model that better simulates permafrost, forest fires, phenology, and that has been optimized against satellite observations of vegetation changes in the last 30 years.
If the increase in plant growth and thus in the seasonal CO2 amplitude will continue in the future, is uncertain. Ongoing climate warming could cause droughts, forest fires, and pests to become more frequent, or could cause the release of carbon from thawing permafrost soils. This could stop the increasing trends in plant growth and the seasonal CO2 amplitude. One of the core objectives of EOWAVE will be to obtain a better understanding of these future feedback mechanisms, and particularly the role of soil moisture herein. To do so, we will use a combination of earth observation data and the improved LPJml ecosystem model used by Matthias in his Science paper.
Press release from Max Planck Society: www.mpg.de/9862783/co2-schwankung-vegetation-erderwaermung
News item from Science: www.sciencemag.org/news/2016/01/what-s-behind-arctic-s-increasing-carbon-dioxide-fluctuations
Enhanced seasonal CO2 exchange caused by amplified plant productivity in northern ecosystems
Matthias Forkel, Nuno Carvalhais, Christian Rödenbeck, Ralph Keeling, Martin Heimann, Kirsten Thonicke, Sönke Zaehle and Markus Reichstein
Science, 21 January 2016, DOI: 10.1126/science.aac497