The International Energy Agency, which provides energy statistics and projections to 28 industrialised countries, has issued a report warning that every year of inaction in cutting carbon emissions will cost the world an additional $US500 billion.

The IEA estimates that in order to limit the rise in global temperatures to 2 degrees, non-fossil fuels will need to provide at least 32 percent of total energy and the share of new cars with internal combustion engines will have to fall to less than 40% by 2030.

The IEA says that to achieve this the world needs to spend a total of $US10,500 billion between 2010 and 2030 on energy efficiency and renewable energy. Each year of delay will increase that figure by $US500 billion.

The IEA estimates that world primary energy demand will rise by an average of 1.5 percent per year over the next two decades and that oil demand, excluding biofuels, will increase by 1 percent per annum to 105 million barrels per day by 2030 from 85 million barels per day in 2008.

While the IEA says that fossil fuel supplies are ample, the Guardian newspaper has quoted two "whistleblowers" who have questioned this claim.

One of the sources was quoted as saying "Many inside the organization believe that maintaining oil supplies at even 90 million to 95 million barrels a day would be impossible but there are fears that panic could spread on the financial markets if the figures were brought down further."

The paper quoted a second senior IEA source as saying that a key rule at the organisation was that it was "imperative not to anger the Americans" but the fact was that there was not as much oil in the world as had been admitted. "We have [already] entered the ‘peak oil’ zone. I think that the situation is really bad," he added.