Future Vegetation Damages from Ozone Pollution: Implication for the Carbon Cycle
Abstract
In the carbon cycle, the present-day sinks due to continental biosphere and oceans are of the same magnitude, however the future response of the continental biosphere to modifications such as climatic change is, nowadays, highly uncertain. Many atmospheric parameters are able to significantly affect the terrestrial carbon sink and several of them are subject to modifications due to human activities. In particular, higher atmospheric CO2 is known to have a fertilizer effect on photosynthesis. Anthropogenic emitted NOx can have a fertilizer effect however it could also have adverse effect on productivity through acid rain. Future climate change can reduce the global efficiency of the vegetation to absorb CO2. Ozone, formed by photochemical reactions involving NOx and VOCs, is responsible of physiological alteration and leaf injury on many plants and thus reduce the carbon sequestration. Future levels of surface O3 in emerging regions (eg. Tropical Africa, Latin America, South East Asia) are expected to increase, and can hence have a significant negative impact on crops and forests. Here we examine the potential impact of O3 on the global terrestrial biosphere for recently developed future scenarios of atmospheric composition and compare with the effects of future climate and CO2 on plant productivity. Ozone levels are computed using the multiscale tropospheric chemistry-transport modelling platform LMDz-INCA/CHIMERE. These ozone exposure distributions are then used by a global dynamic vegetation model ORCHIDEE in order to quantify the changes in net primary production of vegetation under several present and future conditions. Results are discussed in detail for regions of interest having both high O3 precursor emissions and large vegetation cover. The effect of ozone changes at the 2030 horizon on the terrestrial biosphere is shown to be moderate compared with that of climate and CO2.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2006
- Bibcode:
- 2006AGUFM.A51B0078S
- Keywords:
-
- 0325 Evolution of the atmosphere (1610;
- 8125);
- 0330 Geochemical cycles (1030);
- 0428 Carbon cycling (4806);
- 0478 Pollution: urban;
- regional and global (0345;
- 4251);
- 1615 Biogeochemical cycles;
- processes;
- and modeling (0412;
- 0414;
- 0793;
- 4805