Tiempo Climate Newswatch

The latest report by the Intergovernmental Panel on Climate Change (IPCC) on the science of climate change concludes that it is "very likely" - a probability of greater than 90 per cent - that the rise in global air temperature since the mid-1900s has been caused by human activity. Data show that the oceans have warmed to a depth of at least 3,000 metres, contributing to sea-level rise. The report predicts that the average world temperature may rise by about three degrees Celsius by the end of the century. Sea level could rise by as much as 59 centimetres over that period, and some projections indicate the complete disappearance of summer sea ice in the Arctic by the year 2100. Heatwaves and periods of heavy rainfall are "very likely" to become more frequent but tropical cyclones, though more intense, may occur less often. The report, the first volume of the IPCC's Fourth Assessment, was released on February 2nd in Paris, France.

"The big message... is the strength of the attribution of the warming to human activities," said Claudia Tebaldi of the National Center for Atmospheric Research in Boulder, Colorado, in the United States. United Nations Secretary-General Ban Ki-moon pointed to the "scientific consensus regarding the quickening and threatening pace of human-induced climate change" and called for the global response "to move much more rapidly as well, and with more determination." IPCC Chair, Rajendra Pachauri, said that the report contained "significant advances" over the previous 2001 assessment. Nevertheless, though the overall message is clear, some uncertainties remain in the detail. The role of clouds in reinforcing or offsetting greenhouse warming is not well-established, neither is the future of Antarctica. The report indicates that the Antarctic ice sheet may well remain too cold for widespread surface melting and could gain in mass as snowfall increases. The possibility of net loss cannot, however, be ruled out as dynamical ice discharge might dominate the mass balance.

China and India re-affirmed their commitment to act on climate change at the World Economic Forum held in Davos, Switzerland. China intends to follow the Kyoto Protocol, said Zhang Xiaoqiang of the National Development and Reform Commission, although it is not legally bound by the agreement. Help from the industrialized world will be necessary to meet its targets, he said, given the inefficient technology that China has. Montek Ahluwalia of India's Planning Commission reported that nuclear power will play a part in reducing greenhouse gas emissions. "It's clear that business as usual is not going to work," he said.

Britain is following the United States' lead in stressing that the major developing nations must be involved in any post-Kyoto agreement. "Without the biggest economies being part of the framework to reduce carbon dependence, we have no earthly hope of success," said Prime Minister Tony Blair during the meeting. Jim Leape, WWF head, agrees. "Ultimately, to succeed, we have to find some way for those emerging economies to meet... development needs and aspirations with a lower carbon footprint," he said. "The challenge is to fashion an agreement that includes the emerging economies in a way that is common but differentiated in terms of responsibility," he continued, pointing out that the rich world had to accept its major contribution to the problem.

Mountain glaciers are melting at an accelerating rate, according to the latest data. Figures for 1995, taken from a sample of 30 glaciers around the world, show an average thinning of two-thirds of a metre, reports the World Glacier Monitoring Service (WGMS) in Zurich, Switzerland. "Today, the glacier surface is much smaller than in the 1980s, this means that the climate forcing has continued since then," said WGMS scientist Michael Zemp. "The recent increase in rates of ice loss over reducing glacier surface areas leaves no doubt about the accelerated change in climatic conditions," he continued.

According to WGMS director Wilfried Haeberli, "we can say there were times during the warmer periods of the last 10,000 years when glaciers have been comparable to what they are now. But it is not the past that worries us, it is the future. With the scenarios predicted, we will enter conditions which we have not seen in the past 10,000 years, and perhaps conditions which mankind has never experienced." The WGMS has forecast the loss of three-quarters of all Alpine glaciers this century.