ON NOVEMBER 29th representatives of countries from around the world will gather in Cancún, Mexico, for the first high-level climate talks since those in Copenhagen last December. The organisers hope the meeting in Mexico, unlike the one in Denmark, will be unshowy but solid, leading to decisions about finance, forestry and technology transfer that will leave the world better placed to do something about global warming. Incremental progress is possible, but continued deadlock is likelier. What is out of reach, as at Copenhagen, is agreement on a plausible programme for keeping climate change in check.
The world warmed by about °C in the 20th century. Every year in this century has been warmer than all but one in the last (1998, since you ask). If carbon-dioxide levels were magically to stabilise where they are now (almost 390 parts per million, 40% more than before the industrial revolution) the world would probably warm by a further half a degree or so as the ocean, which is slow to change its temperature, caught up. But CO2levels continue to rise. Despite 20 years of climate negotiation, the world is still on an emissions trajectory that fits pretty easily into the “business as usual” scenarios drawn up by the Intergovernmental Panel on Climate Change (IPCC).
The Copenhagen accord, a non-binding document which was the best that could be salvaged from the summit, talks of trying to keep the world less than 2°C warmer than in pre-industrial times—a level that is rather arbitrarily seen as the threshold for danger. Many countries have, in signing the accord, promised actions that will or should reduce carbon emissions. In the World Energy Outlook, recently published by the International Energy Agency, an assessment of these promises forms the basis of a “new policies scenario” for the next 25 years (see chart 1). According to the IEA, the scenario puts the world on course to warm by °C by 2100. For comparison, the difference in global mean temperature betwee
坎昆气候大会报告 来自淘豆网m.daumloan.com转载请标明出处.
