How accurate are our predictions of C-sequestration capacity in a global change scenario?

Rising atmospheric CO2 concentration enhances plant productivity and hence the export of C-compounds to the below-ground ecosystem components. This means that under future atmospheric conditions, we expect belowground release of CO2 to increase, following increased aboveground uptake. However, these predictions are only based in observations in young and fast-growing forests and grasslands. Yet, old forests, which are one of the most important carbon storage compartments of the Earth, might not necessary behave according to these predictions. We have measured CO2 release from the soil and CO2 uptake from the canopy at gradually increasing CO2 atmospheric concentrations and our results shows that we might have overestimated the ability of our forest to actually sequestrate CO2. Read the whole story on our recent paper in Global change biology!