IPCC report urges swift action on global warming
The world's top scientific authority on climate change is set to adopt a landmark report that warns that the impacts of global warming are already visible, will accelerate this century and are potentially irreversible.
The document, crafted by the United Nations' Intergovernmental Panel on Climate Change (IPCC), summarises the first overview on the greenhouse-gas effect since 2001.
It is styled as a guide for politicians facing tough decisions on cutting pollution from fossil fuels, shifting to cleaner energy and bolstering defences against drought, flood, storms and other problems that are set to intensify through climate change.
The IPCC is going to adopt a 20-page "summary for policy-makers" and a 70-page technical document.
These will be followed by a press conference attended by UN secretary-general Ban Ki-moon, who has warned that the world is on the verge of a "catastrophe" due to global warming.
The report encapsulates three phonebook-sized assessments, issued earlier this year, that effectively consign once-powerful "climate sceptics" to a small and shrinking minority.
The IPCC says the evidence of a human role in observed warming is now "unequivocal".
It says retreating glaciers and snow loss in alpine regions, thinning Arctic summer sea ice and thawing permafrost show that climate change is already on the march.
By 2100, global average surface temperatures could rise by between 1.1 and 6.4 degrees Celsius, compared to 1980-99 levels, while sea levels will rise by between 18 and 59 centimetres, the IPCC forecasts.
Heatwaves, rainstorms, water stress, tropical cyclones and surges in sea level are among the events expected to become more frequent, more widespread and/or more intense this century.
The draft of the new report warns that all countries will be affected but poorer countries - ironically those least to blame for causing the problem - will be hit hardest and have the least resources for coping.
Publication of the synthesis comes in the run-up to a conference in Bali, in Indonesia, where the world's nations will gather to ponder the climate crisis.
The December 3-14 conference of the UN Framework Convention on Climate Change (UNFCCC) is tasked with setting a "roadmap" of negotiations for intensifying cuts in carbon emissions beyond 2012, when the Kyoto Protocol runs out.
Carbon pollution, emitted especially by the burning of oil, gas and coal, traps heat from the Sun, thus warming the Earth's surface and causing changes to weather systems.
Emissions are spiralling, driven more recently by coal-fired plants in fast-growing China and India.
In its present form, Kyoto will not even make a dent in this threat.
In a commentary published in the International Herald Tribune today, Mr Ban called for urgent action on global warming.
"I believe we are on the verge of a catastrophe if we do not act," he wrote.
"I am not scare-mongering. But I believe we are nearing a tipping point."
But Mr Ban has characterised the IPCC report's conclusions as "encouraging".
"The over-arching message: we can beat this," he wrote.
"There are real and affordable ways to deal with climate change."