IN FEBRUARY we heard from the Intergovernmental Panel on Climate Change that it is now indisputable that humans have changed the global climate. Last week the IPCC reported equally hard-hitting evidence that climate change is already having an impact, and that the world鈥檚 poor will be hit hardest.
The release of a summary of the latest report 鈥� the second of three due this year 鈥� was held up by political wrangling. Arguments continued through the night of 5 April and until well after the scheduled release time the following morning. Despite the attempts at watering down that some scientists say kept the report鈥檚 authors from their beds, the message comes through clearly: climate change is affecting the world鈥檚 ecology.
鈥淭he latest IPCC chapter is the first to use observations of the Earth鈥檚 climate rather than predictions of possible future scenarios to conclude that climate change is real,鈥� says Saleem Huq of the non-governmental International Institute for Environment and Development, one of the report鈥檚 authors.
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鈥淭he latest IPCC chapter is the first to use observations of the Earth鈥檚 climate to conclude that climate change is real鈥�
鈥淔ive years ago, we said we could detect a regional impact of climate change,鈥� says Martin Parry of the UK鈥檚 Met Office. Parry co-chaired the group of 441 scientists who worked on the latest report and synthesised five years鈥� worth of research conducted since the previous IPCC report in 2001. 鈥淣ow we have reviewed 29,000 data sets, and 90 per cent of them show that changes happening worldwide are due to climate change,鈥� he says.
The report details how different amounts of global warming 鈥� from no change to 5 掳C on average 鈥� would affect human societies. It also explicitly emphasises that the people who will be affected most are the world鈥檚 poorest. These are also the people who have done least to increase levels of greenhouse gases in the atmosphere.
For example, the report predicts that less water will be available in semi-arid low latitudes, such as sub-Saharan Africa, and that even a 1 掳C warming will decrease agricultural yields in these areas. 鈥淭hat is exactly what we do not want,鈥� says Parry, because countries in these latitudes tend to be relatively poor and ill-equipped to adapt to such changes.
The report says that climate change will cause immediate and unavoidable harm. This will include less food from farming in some areas, more violent storms, more drought and heatwaves, early flowering seasons, changes in insect migrations and the dwindling of water supplies as mountain glaciers melt.
Things we need to do, the report recommends, include building dykes to protect coastal developments from rising sea levels and developing genetically modified crops that can grow with less water. Greenhouse gas emissions must also be cut to avoid making warming so severe that such measures will be overwhelmed.
Joseph Alcamo of the University of Kassel in Germany, who is coordinating lead author of the report鈥檚 chapter on the effects of climate change in Europe, told 快猫短视频 that many scientists were irritated by the political delegations鈥� wrangling over conclusions that had been discussed and resolved during the peer review process. 鈥淪ome delegations go back and spend a lot of unnecessary time in challenging the scientific credibility.鈥� The final negotiations are 鈥渘ot the right place to do that鈥�, he says.
Huq identified Saudi Arabia, China, Russia and the US as the worst culprits. Catherine Brahic, Brussels
