The changes in the global biogeochemical carbon cycle become more and more obvious; however, the relative contributions of natural and anthropogenic activities are still uncertain. However, the role of carbon dioxide in the Earth's historical radiation budget merits modern interest in raising atmospheric CO2. The relative changes include both climate changes and environmental pollution.
Critical loads have been widely used to formulate European emission reduction policies for sulfur and nitrogen. The critical load values depend on the ecosystem characteristics that might be altered due to climate changes. An investigation of the impact of different scenarios of climate change on critical loads and their exceedances is of both scientific and political interests.
Recent estimates have shown that the acidity critical loads will be exceeded only in small parts of Europe under all scenarios. It should be borne in mind, however, that: (1) nonexceedance does not mean immediate recovery, and (2) higher-resolution deposition fields, capturing some of their small-scale variability, would certainly lead to more widespread exceedances.
Eutrophication, on the other hand, will continue to be a problem even under the most stringent scenario. This confirms the important and increasing role nitrogen plays in environmental problems, both in its oxidized and reduced forms. Thus, research should focus on the effects of nitrogen in the environment, especially under conditions of climate change, whereas policies should concentrate on further reductions of nitrogen emissions. This not only reduces acidification and eutrophication, but also helps curbing the formation of tropospheric ozone.
Furthermore, the global overview on the carbon bio-geochemical cycle should point out its interaction with other cycles such as that of nitrogen and sulfur both for the respective and perspective trends.
See a/so: Climate Change 1: Short-Term Dynamics; Plant Defense.
Was this article helpful?