Progress towards the use of cleaner fuel technology has stalled, with production of the world's energy as "dirty" now as it was two decades ago, the International Energy Agency said Wednesday.
Two-thirds of greenhouse gas emissions come from the energy sector and the lack of change should "serve as a wake-up call", the IEA's executive director Maria van der Hoeven told a Clean Energy Ministerial meeting in New Delhi.
She warned that with increases in wind and solar energy being offset by increased coal use in countries such as China and India, the world needed to act fast "to avoid a potentially catastrophic warming of the planet".
"Despite much talk by world leaders and despite a boom in renewable energy over the last decade, the average unit of energy produced today is basically as dirty as it was 20 years ago," Van der Hoeven said.
"The drive to clean up the world's energy system has stalled."
The Paris-based IEA has developed an Energy Sector Carbon Intensity Index, which indicates how much carbon dioxide is emitted on average to provide a given unit of energy, she said.
The index for the world's energy stood at 2.39 tonnes of carbon dioxide per tonne of oil equivalent in 1990 and had barely moved by 2010, holding at 2.37 per tonne of oil equivalent.
While there has been investment in new forms of clean energy, such as solar or wind power, these benefits have been counter-balanced by the increasing use of carbon-intensive coal by rising economic powers such as China and India.
"Our analysis is stark reminder the world is not on track to realise the benefit of a low-carbon energy system—to limit long-term temperature rises to two degrees centigrade," the IEA head said.
"We cannot afford another 20 years of listlessness," she said, calling for a rapid expansion in low-carbon energy technologies.
Clean energy investment fell to its lowest in four years in 2012, she said at the Clean Energy Ministerial which brought together 22 countries and the European Union that are responsible for 80 percent of global greenhouse gas emissions.
Explore further: IEA backs renewable energy