Competing roles of rising CO₂ and climate change in the contemporary European carbon balance

R. Harrison (1) , C. Jones (1)

1 MOHC - Met Office Hadley Centre

Natural ecosystems respond to, and may affect climate change through uptake and storage of atmospheric CO₂. Here we use the land-surface and carbon cycle model JULES to simulate the contemporary European carbon balance and its sensitivity to rising CO₂ and changes in climate. We find that the impact of climate change is to decrease the ability of Europe to store carbon by about 175 TgC yr^?1. In contrast, the effect of rising atmospheric CO₂ has been to stimulate increased uptake and storage. The CO₂ effect is currently dominant leading to a net increase of around 150 TgC yr^?1. Our simulations do not at present include other important factors such as land use and management, the effects of forest age classes and nitrogen deposition.

There seems to be an emerging consensus that changes in climate will weaken the European land-surface's ability to take up and store carbon. It is likely that this effect is happening at the present and will continue even more strongly in the future as climate continues to change. Although CO₂ enhanced growth currently exceeds the climate effect, this may not continue indefinitely. Understanding this balance and its implications for mitigation policies is becoming increasingly important.

Domaines: Cosmologie et astrophysique extra-galactique [astro-ph.CO]; Astrophysique [astro-ph]; Interfaces continentales, environnement; Océan, Atmosphère; Sciences de la Terre

R. Harrison, C. Jones. Competing roles of rising CO₂ and climate change in the contemporary European carbon balance. Biogeosciences Discussions, 2007, 4 (4), pp.2385-2405. ⟨hal-00297907⟩