Carbon sinks and conserving biodiversity.

Abstract

Although carbon sequestration through better management of forests and farmland does not provide a long-term alternative to reducing greenhouse gas emissions, it might provide limited and short-term benefits for the climate. The Kyoto Protocol of the United Nations Framework Convention on Climate Change allows Land Use, Land Use Change and Forestry (LULUCF) projects under certain constraints. These projects include a planned set of activities designed to enhance carbon sequestration in terrestrial ecosystems. Concerns have been raised about the potential effect of such projects on biodiversity; for example, that old growth, biodiversity-rich forests could be replaced by plantations of fast-growing trees. However, under a number of circumstances, win-win situations could be created between climate change mitigation and biodiversity conservation, and these were the topic of discussion at the international conference “Carbon Sinks and Biodiversity” held in Liege, Belgium, in October. For example, in developed countries and countries whose economies are in transition, ecosystem restoration through revegetation of a fraction of noncultivated agricultural and marginal lands offers a potential for climate change mitigation. This requires taking all greenhouse gas fluxes into account. Such revegetation can be achieved in a number of ways, including by encouraging the use of biofuels and chemicals derived from biomass. Peatlands could be protected and former peatlands converted back to either their original state or some other managed state with higher water tables. Afforestation of peatlands should generally be avoided, as it would endanger biodiversity and the greenhouse gas balance of such ecosystems. In developing countries, measures to avoid deforestation and to restore native forests strike a good balance between climate change mitigation and conservation of biological diversity. Policies for the conservation and sustainable use of existing forests should be aimed at increasing rural incomes, empowering local users of forests, and promoting good governance of natural resources. Because measures to avoid deforestation would be difficult to translate into verifiable greenhouse gas emission credits in the Kyoto Protocol, they should be promoted through other policies. Sustainable agroforestry systems should be promoted as a form of land management for mitigating climate change and for biological diversity conservation, because these provide numerous socioeconomic and environmental benefits. Whereas the potential of carbon sequestration measures in a given terrestrial ecosystem mainly depends on the quantity of land that would be managed for this purpose, biodiversity conservation also depends on the landscape spatial pattern. Therefore, land use planning is important to optimize climate change mitigation through carbon sinks while maintaining or developing conservation areas, for example, through protected reserves and reforestation of corridors and buffer zones. Potentially, there are large synergies between LULUCF projects within the Kyoto Protocol and the objectives of the Convention on Biological Diversity, but for these to be realized, we need effective coordination between these international conventions, and among national policies on land use and natural resource management. Measures that ensure a long-term reduction in greenhouse gas emissions should always have priority over carbon sinks, as the latter only have short-term benefits for the climate. However, LULUCF projects will yield other long-term benefits when they have positive impacts on ecosystem functioning, including biodiversity conservation.