Climate change is already affecting global biodiversity and the situation is not expected to improve soon. Rising temperatures and regular extreme events will produce new selection pressures. These will force many species to move to find more suitable conditions, or adapt. Their ability to respond to these pressures will depend on the rate and extent of change, their ability to adapt to new conditions or their ability to move away. Understanding how biodiversity responds to climate change requires an interdisciplinary perspective, combining ecological, molecular and environmental approaches.
Emissions from fossil fuels have led globally to an increase in atmospheric concentrations of greenhouse gases. These changes are projected to lead to regional and global changes in climate. This will add an additional stress to ecological systems already affected by pollution, increasing resource demands and unsustainable management practices. Composition and geographical distribution of ecosystems will shift more rapidly than they have previously according to natural processes. Subsequently, the limited capacity of some species for adaptation to these changes will pave the way for increased losses in biodiversity.
Ozone depletion, climate change, and biodiversity loss have the potential to deepen every resource scarcity issue. Climate change will affect food production and aggravate water scarcity. Ozone depletion will also effect food production-through increased UV-B exposure-and fisheries-through disturbances to the ocean's phytoplankton food chain. Loss of biological diversity has the potential to reduce crop yields and fish take as sources of wild germplasm disappear and marine ecosystems become damaged and degraded.
A number of global processes have serious impacts on biodiversity in particular climate change, desertification, ozone layer depletion. The impact of climate change on some sensitive ecosystems and crop varieties as well as the effects of some actions to combat climate change can be relevant to the objectives of the Convention on Biological Diversity (CBD).
Policies related to the conservation and sustainable use of biodiversity should take into account changes that could occur in ecosystems as a consequence of the accelerated rate of change in climate. The effects of ozone layer depletion on marine productivity and on fisheries, as well as on some crop varieties and the impact of the use of some ozone depleting substances on local biodiversity are equally important.
Climate change is the latest emerging threat to biodiversity in Africa. It has already been identified as a contributing cause in the decline of amphibian populations, due to drastic reductions in the volume of water bodies after persistent dry weather in combination with intensified human activities along the shorelines.