This hardly requires comment...

Global warming has already hit the danger point that international attempts to curb it are designed to avoid, according to the world's top climate watchdog.

Dr Rajendra Pachauri, the chairman of the official Intergovernmental Panel on Climate Change (IPCC), told an international conference attended by 114 governments in Mauritius this month that he personally believes that the world has "already reached the level of dangerous concentrations of carbon dioxide in the atmosphere" and called for immediate and "very deep" cuts in the pollution if humanity is to "survive".

His comments rocked the Bush administration - which immediately tried to slap him down - not least because it put him in his post after Exxon, the major oil company most opposed to international action on global warming, complained that his predecessor was too "aggressive" on the issue.

A memorandum from Exxon to the White House in early 2001 specifically asked it to get the previous chairman, Dr Robert Watson, the chief scientist of the World Bank, "replaced at the request of the US". The Bush administration then lobbied other countries in favor of Dr Pachauri - whom the former vice-president Al Gore called the "let's drag our feet" candidate, and got him elected to replace Dr Watson, a British-born naturalized American, who had repeatedly called for urgent action.

But this month, at a conference of Small Island Developing States on the Indian Ocean island, the new chairman, a former head of India's Tata Energy Research Institute, himself issued what top United Nations officials described as a "very courageous" challenge.

He told delegates: "Climate change is for real. We have just a small window of opportunity and it is closing rather rapidly. There is not a moment to lose."

Afterwards he told The Independent on Sunday that widespread dying of coral reefs, and rapid melting of ice in the Arctic, had driven him to the conclusion that the danger point the IPCC had been set up to avoid had already been reached.

Reefs throughout the world are perishing as the seas warm up: as water temperatures rise, they lose their colors and turn a ghostly white.

Partly as a result, up to a quarter of the world's corals have been destroyed.

And in November, a multi-year study by 300 scientists concluded that the Arctic was warming twice as fast as the rest of the world and that its ice-cap had shrunk by up to 20 per cent in the past three decades.

The ice is also 40 per cent thinner than it was in the 1970s and is expected to disappear altogether by 2070. And while Dr Pachauri was speaking parts of the Arctic were having a January "heatwave", with temperatures eight to nine degrees centigrade higher than normal.

He also cited alarming measurements, first reported in The Independent on Sunday, showing that levels of carbon dioxide (the main cause of global warming) have leapt abruptly over the past two years, suggesting that climate change may be accelerating out of control.

He added that, because of inertia built into the Earth's natural systems, the world was now only experiencing the result of pollution emitted in the 1960s, and much greater effects would occur as the increased pollution of later decades worked its way through. He concluded: "We are risking the ability of the human race to survive."

So, here's an interesting sequence to ponder some sleepness night: (1) Studies reported last week and last month suggest that the most likely cause of the mass extinction known as the "Great Dying" (250 million years ago) was not an asteroid or comet, but climate warming caused by volcanic gases. (2) Bush's own handpicked climate change lobbyist thinks global warming is accelerating out of control. And (3), many scientists believe we have entered another - the Earth's sixth - mass extinction. Here are two good info "portals" - one on mass extinctions and one on climate change.