It may also lead to the disappearance of some small island states, such as the Maldives which have an average height of about 1.5m above sea level. Climatic zones, and thus ecosystems and agricultural zones, will shift towards the poles as temperatures rise. In some cases shifts could be up to 300km per degree Celsius. Forests, deserts, rangelands, and other unmanaged ecosystems will face new climatic stresses. Many ecosystems will decline or fragment, and individual species which are not able to adapt or migrate will become extinct.
Coral reefs are an example of an ecosystem already exhibiting signs of major damage.
Severe bleaching of corals worldwide has occurred as a result of warmer surface water temperatures. The Worldwide Fund for Nature predicts that by 2100 up to one third of natural habitats may be destroyed by climate change. We may have already witnessed the first documented example of species extinction due to climate change. As a result of changing rainfall patterns, the golden toad has disappeared from the cloud forests of Costa Rica. Forests and agriculture Increased levels of CO2 will initially lead to increased plant growth and expansion of forests in some areas.