The warning from the Paris-based agency comes just a month ahead of the major United Nations climate conference in Copenhagen, where world leaders hope to agree on so-called climate finance to help developing countries cut emissions by switching from fossil fuels to cleaner energy, such as wind and solar.

The European Union has said that there should be a €100-billion (US$150-billion) annual package of public and private finance by 2020 to help poorer nations develop green industries and adapt to climate change.

US$90-billion drop

The IEA, a policy adviser to 28 mostly industrialised oil-consuming nations, estimates that the financial and economic crisis is responsible for a US$90-billion drop in global oil and gas investments this year, a 19 per cent cut from 2008.

"Falling energy investment will have far-reaching and, depending on how governments respond, potentially serious consequences for energy security, climate change and energy poverty," the IEA said, in its annual World Energy Outlook report.

The resulting drop in oil and electricity supplies could "undermine the sustainability of the economic recovery," the IEA warned.

Meanwhile, oil demand is set to continue rising over the next two decades, with a drop in developed countries oil use more than offset by increases in the developing world, mainly China and India, the IEA said.

The IEA forecast global oil demand would rise to 105 million barrels a day by 2030, up from 85 million barrels a day last year.

The new forecast is slightly lower than the 106 million barrels a day that the IEA forecast last year, before the global economic downturn spurred a steep drop in energy use in the developed world.

Investment in renewable energy sources has been particularly hard hit by the downturn, falling by about one-fifth in 2009 compared to a year earlier.

Stimulus plans

Without the stimulus plans enacted by governments in response to the crisis, renewable energy investments would have fallen 30 percent this year, the IEA said.

"The financial crisis has cast a shadow over whether all the energy investment needed to meet growing energy needs can be mobilised," the IEA warned.

The agency estimates that US$1.1 trillion needs to be invested annually from now until 2030, for a total of US$26 trillion, just to meet energy demand on current growth trends.

Should governments adopt plans to limit greenhouse gas concentrations in the atmosphere to 450 parts per million of CO_² equivalent, an additional US$10.5 trillion needs to be invested over that time period, the IEA said.