We are all familiar with the term 鈥渃limate change鈥�, but 鈥渃limate replacement鈥� might be more accurate, or even 鈥渃limate disappearance鈥�. In 100 years half the world鈥檚 climates may have vanished for good as a result of global warming.
That鈥檚 the conclusion of the first assessment of how all climates will be affected as the world heats up. Gone too will be thousands of species, and new types of climate will emerge, with higher temperatures and more rain.
鈥淚t鈥檚 the coldest climates that would be replaced,鈥� says John Williams of the University of Wisconsin, Madison. As temperatures rise by several degrees, so glaciers will retreat and ice disappear from mountains such as Kilimanjaro. New types of climate would emerge in more tropical regions, particularly the Amazon and Indonesian rainforests. 鈥淲hat we鈥檙e concerned about is what happens to the species in these regions,鈥� says Williams. The only options are migrating or adapting, but some will have nowhere to migrate to, or will be outcompeted by invading species.
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Williams and his colleagues assessed both small-scale and global effects on climate using the latest projections developed by the UN Intergovernmental Panel on Climate Change for high and low emissions of carbon dioxide.
Comparing best and worst outcomes, the team estimates that between 20 and 40 per cent of the world鈥檚 land would develop completely novel climates, and existing climates would vanish in 20 to 48 per cent of land area (Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.0606292104). 鈥淭here鈥檚 a big difference, so reductions in carbon dioxide do give cause for hope,鈥� says Williams.
