LANDMARK CLIMATE REPORT ISSUES STRONG WARNING ON GLOBAL WARMING

A group of the world's top climate scientists has issued its strongest ever warning that human activity is to blame for climate change, and that global temperatures and extreme weather phenomena will increase unless greenhouse gas emissions are substantially reduced.

In a report issued on 2 February, the Intergovernmental Panel on Climate Change (IPCC) - the scientific body examining global climate research - said that evidence for the "warming of the climate system is unequivocal," from rising sea levels to increased temperatures. The panel, which comprised 2500 scientists from more than 130 nations and representatives of 113 governments, said that it was more than 90 percent certain that global warming was caused by human activity. An earlier study in 2001 had only been able to peg the probability at somewhere above two-thirds. Climate scientists are now more confident about their ability to project future warming and weather patterns, the report said.

The IPCC's findings are regarded as the 'most authoritative science' on global warming. Entitled "Climate Change 2007: The Physical Science Basis," the report states that "most of the observed increase in globally averaged temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic (human-generated) greenhouse gas concentrations." These levels are the highest seen in 650,000 years.

The report forecasts a probable temperature rise between 1.8-4C by 2100, though this could vary from 1.1C to 6.4C. The 2001 report forecasted a more limited range, between 1.4 and 5.8C. It projects a rise in sea levels of between 18 and 59 cm this century, the disappearance of Arctic summer sea-ice in the second half of the century, an increase in heatwaves and in the intensity of tropical storms, and increased desertification.

Rajendra Pachauri, the IPCC chair, noted that as the report was discussed and debated by governments and the final content based on consensus, it had the stamp of acceptance by all governments. This provided credibility to what he termed a 'massive scientific undertaking.'

Sharon Hays, associate director of the White House Office of Science & Technology Policy, called the report "a comprehensive and accurate reflection of the current state of climate change science." She added that US President George W. Bush had "put in place a comprehensive set of policies to address what he has called the 'serious challenge' of climate change" and that the current set of policies were working (see BRIDGES Weekly, 31 January 2007). The US is the world's leading emitter of greenhouse gases, responsible for about a quarter of the global total. However, it has not put in place binding requirements to reduce emissions, whether through the Kyoto Protocol or under domestic law.

"We are on the verge of the irreversible," said French President Jacques Chirac. David Millibank, the UK environment secretary, declared that the "debate over the science of climate change is well and truly over," calling for international political commitment to take action. He stated that the report would provide "a strong evidence base needed to move the prospects of agreement closer."

Sounding a warning note, Stephanie Turnmore from Greenpeace remarked that if the last IPCC report was a wake-up call, this one was a screaming siren.

This report is the first of four reports that will together constitute the IPCC's Fourth Assessment Report. While it looks at the science of climate change, the forthcoming ones will look at impacts, adaptation and vulnerability and mitigation. Finally, a synthesis report will also be released in time for the December conference of parties (COP-13) to the UN Framework Convention on Climate Change (UNFCCC) in Indonesia. According to Pachauri, the synthesis report would not be 'policy-prescriptive' but would be 'highly policy relevant'.

The IPCC was established by the UN Environment Programme and the World Meteorological Organisation in 1988 with a role to assess the scientific basis for the risk of human-induced climate change, its potential impacts and options for adaptation and mitigation. The IPCC's assessments are based on peer-reviewed and published scientific and technical literature. The first assessment report was published in 1990.

A 21-page summary of the IPCC report is available at http://www.ipcc.ch.

ICTSD reporting; "Human Blamed for Climate Change," BBCNEWS, 2 February 2007; "At a Glance: IPCC report," BBCNEWS, 2 February 2007; "U.N. Climate Panel Says Warming is Man-made," REUTERS, 2 February 2007; "FACTBOX-U.N. Climate Panel Report," REUTERS, 2 February 2007; "Q&A: The IPCC Report on Global Warming," GUARDIAN UNLIMITED, 2 February 2007.