Scientists must be more 'honest and open' about the uncertainties of global warming, the Government's chief scientific adviser declared yesterday.

Professor John Beddington said climate researchers should be less hostile to sceptics who question their predictions.

But he added that the underlying physics of climate change - that carbon dioxide released by burning fossil fuels warms the planet - was 'unchallengeable'.

Professor Beddington's comments follow a series of blunders by climate scientists.

Last week, the UN's Intergovernmental Panel on Climate Change was forced to apologise after wrongly claiming most of the Himalayan glaciers would vanish within 25 years.

The warning, which appeared in the IPCC's 2007 report, turned out to be taken from a news story from New Scientist magazine in the late 1990s based on an interview with a glacier expert. The expert later admitted his comment was speculation.

In November, leaked emails appeared to show scientists at the University of East Anglia manipulating data to strengthen the case for man-made climate change - and debating ways to stop sceptics getting hold of their raw temperature data.

Professor Beddington said public confidence in climate science would be boosted by greater honesty about its uncertainties.

'I don't think it's healthy to dismiss proper scepticism,' he said.

Glaciers: Claims they will melt by 2035 were not backed up, the UN said

'Science grows and improves in the light of criticism. There is a fundamental uncertainty about climate change prediction that can't be changed.'

He said that the false claim about glaciers in the IPCC report revealed a wider problem with the way that some evidence was presented.

'Certain unqualified statements have been unfortunate,' he added.

'We have a problem in communicating uncertainty. There's definitely an issue there. If there wasn't, there wouldn't be the level of scepticism.

'All of these predictions have to be caveated by saying, "There's a level of uncertainty about that".'

Professor Beddington also said that computer climate modelling resulted in 'quite substantial uncertainties' that should be communicated.

'It's unchallengeable that CO2 traps heat and warms the Earth and that burning fossil fuels shoves billions of tonnes of CO2 into the atmosphere,' he told the Times.

'But where you can get challenges is on the speed of change. When you get into large-scale climate modelling there are quite substantial uncertainties.

'On the rate of change and the local effects, there are uncertainties both in terms of empirical evidence and the climate models themselves.'

The UN is under increasing pressure to reform the IPCC - and include research from sceptical scientists in its reports.

Dr Benny Peiser, of the Global Warming Policy Foundation thinktank, said of Professor Beddington's remarks: 'His public rebuke is a highly significant development which we hope will help to restore some much needed balance and realism to the climate debate.'