Flowers now but nowhere to go

By the end of the century up to two fifths of the land surface of the Earth may have a hotter climate unlike anything that currently exists, according to a study that predicts the effects of global warming on local and regional climates. The changes, which would have a devastating effect on biodiversity hotspots such as the Amazonian and Indonesian rainforests, may wipe out numerous species that are unable to move to stay within their preferred climate range. These species will either have to evolve rapidly or die out. “There is a real problem for conservation biologists,” says John Williams, at the University of Wisconsin at Madison, lead author on the paper in the Proceedings of the National Academy of Sciences, published online. “How do you conserve the biological diversity of these entire systems if the physical environment is changing and potentially disappearing?” “Studies already suggest that the ranges of species are shifting towards the poles at around six kilometres a decade, but what will happen when the rate of change intensifies?” The team used emission scenarios set out by the Intergovernmental Panel on Climate Change (IPCC) to predict where changes in temperature and precipitation would occur. As is already happening, the analysis predicts that, as the planet warms, climate zones will move north and south towards the poles. To work out the significance of these changes, the team compared them with the climate change that occurs naturally. They attach greater weight to changes in regions that are relatively stable. This suggests that some of the worst aspects will happen in tropical and subtropical regions as they shift to new climatic conditions not currently seen.