Polar bears
Polar bear habitat being destroyed by climate change (Reuters)

The Intergovernmental Panel on Climate Change (IPCC) report is a "clear signal" that world leaders need "less talk and more action" to combat the effects of global warming.

The report says scientists are 95% certain the dominant cause of climate change is mankind.

Despite the report using more than two million gigabytes of numerical data from climate model simulations and 9,200 scientific publications, three quarters of which have been published since the last ICPP assessment in 2007, some climate change sceptics refused to accept the findings.

But Telegraph journalist and broadcaster James Delingpole said the report had been "sexed up".

"The scientific reality - that global warming has paused for 15 years, that climate sensitivity appears to be far smaller than the scaremongering computer models predicted - cannot be allowed to derail all the expensive and intrusive programmes (from windfarms to green investment banks to hideous, flickery, dull low-energy lightbulbs) which have been introduced in order to 'combat climate change'," he wrote for the Telegraph.

Other sceptics suggest concerns over climate change are irrational or far off. Myron Ebell, of the US Competitive Enterprise Institute, told the Guardian: "We should be worried that the alarmist establishment continues using junk science to promote disastrous policies that will make the world much poorer and will consign poor people in poor countries to perpetual poverty."

Wind farms
Eco-friendly wind farms considered unsightly by many climate skeptics (Reuters)

Climate scientists who are also fellows of the Royal Society expressed different views on the report.

John Shepherd, from the University of Southampton, said: "As expected, the main message is still the same: the evidence is very clear that the world is warming, and that human activities are the main cause.

"Natural changes and fluctuations do occur but they are relatively small. There are still uncertainties but the signal is clear enough to justify action: in fact we need less talk and more action. Uncertainty is a reason to be cautious, but not a reason to do nothing. On the contrary, uncertainty is a reason for taking action to avoid possible serious risks."

He added that the recent slow-down in warming may be caused by a natural cycle, which means more rapid warming should be expected in the coming years. "There is no reason whatever to suppose that the slow-down is permanent," he said.

Sir Brian Hoskins, from Imperial College London, said: "This report significantly strengthens the consistent message from the four previous assessment reports; we are conducting a dangerous experiment with our planet.

"The evidence of changes in many different aspects of the climate system, from the ice sheets to the deep ocean, shows that climate change is happening. To reduce the serious risks posed by increasing changes in the climate, we need to redouble our efforts globally to limit carbon dioxide and other greenhouse gas emissions."

The report was welcomed by the Royal Society (IPCC)