The IPCC summary or synthesis report - to be released on 17 November following a week-long meeting of IPCC delegates from over 140 countries in Valencia, Spain - will be "an essential trigger for the launch of negotiations for a global climate agreement", according to John Hay of the United Nations Framework Convention on Climate Change (UNFCC).
World leaders are preparing to meet in Bali, Indonesia, from 3-14 December for a major UN climate change conference designed to prepare negotiations towards a successor to the Kyoto Protocol, which expires in 2012.
The IPCC's summary, accompanied by a 70-page technical annex, will be on hand during the Bali talks to serve as a guidance document.
In February, the IPCC described it as 'very likely' that global warming is a man-made phenonemon and said that policymakers need to take rapid and tough action to prevent major fallout from climate change.
But despite the IPCC's dire warnings - which include a 50% reduction in crop yields by 2020, widespread biodiversity loss and catastrophic flooding - a number of climate change experts are concerned that the summary report will fail to take into account more recent phenomena, such as the rapid melting of Arctic and Greenland ice and an apparent slowing of the planet's capacity to absorb greenhouse gases (GHGs).
"The IPCC's slowness means that it is indeed well behind the state of the knowledge," lamented James Hansen of the NASA Goddard Institute for Space Studies in New York. And "even the gloomiest of the IPCC predictions underestimate the severity of climate change," according to British scientist James Lovelock.
Environmental groups such as the WWF are also concerned, according to press reports, that the content and conclusions of the summary will be influenced by political considerations and downplayed in order to alleviate the pressure on some countries to push through costly measures to reduce CO2 emissions.
