And the documents warn that rising pollution will inevitably increase the warming. They also say that the warming of the past century is likely to have been at least partly caused by increasing emissions of carbon dioxide and other greenhouse gases, such as methane and nitrous oxide. This screened out some of the Sun’s radiation, causing temperatures to drop until 1993. But as the dust has settled back to earth, temperatures have risen again.The episode has helped strengthen the scientists’ belief in global warming, partly because it shows that the climate responds to changes in the atmosphere, and partly because computer models that experts use to calculate global warming predicted the after-effects of the explosion.The IPCC documents say that the new evidence indicates “a detectable human influence on global climate”. The lull was caused by the eruption in 1991 of Mount Pinatubo, a volcano in the Philippines, which threw 20 million tons of sulphur into the upper atmosphere.
Global average temperatures have increased by between 0.3 degrees and Centigrade and 0.6C since the late 1890s; and most of this increase has taken place in the past 40 years.As a result, the seas have risen between 10cm and 25cm so far this century, partly from the melting of glaciers (which have shrunk further in Europe, for example, than at any time in the last 5,000 years), partly from the break-up of ice sheets, and partly because sea-water expands as it becomes warmer.Winter rainfall has increased over Europe, Russia and North America – a sign of warming – while snow cover in the Northern Hemisphere has fallen by 10 per cent over the past 20 years.The warming has resumed during the past two years after a brief lull. Nine of the ten warmest years on record have occurred since the early 1980s.The documents summarising the IPCC report – which is likely to be approved by world governments at a conference in Rome in December – say that this century has been the warmest ever recorded. Until recently, they thought that we would have to wait until the end of the century to be sure that pollution is warming the climate. But with the help of greatly improved scientific techniques, they have decided that there are enough signs already that this is happening.Over the past year, it has been established that flowers and grasses have been spreading rapidly in the north of Antarctica; that several of the frozen continent’s ice sheets have disintegrated; that the seas are rising faster than had been thought; and that there are ominous signs of changes in the North Atlantic that may affect the Gulf Stream.All these developments were first reported in the Independent on Sunday, and last November we forecast that this would be a very warm year It is now clear that it is one of the hottest ever. And they warn that Britain and Northern Europe, despite the recent run of hot summers and mild winters, could rapidly become colder because of changes in the Gulf Stream.In its last principal report, in 1990, the IPCC said that although the world had grown warmer over the last century, it was not possible to attribute any or all of this to human activities.
The energy industries and their supporters, and the oil-producing countries, have used this report, as well as the work of a small number of dissident scientists, to deride the risks.Now the experts have reached a consensus rare in science. The report is summarised in two confidential draft documents obtained by the Independent on Sunday.The consensus of 2,000 top meteorologists and other experts consulted by the IPCC is that tropical diseases will increasingly spread into temperate areas, that droughts and floods will increase, that forests will die out, and that harvests in poor countries could fall dramatically. But a new report, from the official Intergovernmental Panel on Climatic Change (IPCC), marks the end of serious argument about the threat of global warming. I get messages from the other staff on my computer saying things like “So what’s it like in the the mortuary shift?”Sometimes I get an urge to take off all my clothes and run naked around the empty building, but I haven’t given into it yet.. THE world’s top scientists have at last reached agreement on global warming – and their message is just about as alarming as it could be for humanity. The world really is warming up, the scientists agree, and pollution is at least partly to blame. They agree also that warming will have dramatic effects – more droughts and floods, for example – and could accelerate out of control.
