Global energy consumption has dropped for the first time in 30 years because of the credit crisis. In its annual World Energy Outlook published today, the International Energy Agency (IEA) also concludes that greenhouse gas emissions have decreased this year.

But as soon as the crisis is over, the IEA expects energy demand to grow worldwide, especially in India and China. Planet-warming carbon emissions are then set to increase by 1.5 percent annually until 2040. A key driver of energy demand would be inexorable growth in power generation - the IEA calculates a 2.5 percent annual growth until 2030.

The IEA also forecasts a surge in energy costs. Oil prices are likely to reach 100 dollars per barrel by 2015 and 190 dollars by 2030. Oil currently costs 79 dollars a barrel.

The IEA is arguing strongly for a global deal at the United Nations Climate Change summit in Copenhagen in December and has said use of fossil fuels was bound to rise if policies remain unchanged.