OSLO (Reuters) - The share of renewable energy will have to rise “dramatically” if the world is to have a chance of limiting global warming to a maximum 2 Celsius (3.6 Fahrenheit) temperature rise, a leading expert said Wednesday.
Ottmar Edenhofer, co-chair of a scientific group due to present a U.N. report on renewable energy in 2010, said clean technology such as wind and solar power needed a big role even if the world also turned increasingly to nuclear power.
“To achieve a 2 Celsius target the share of renewables has to be increased substantially and dramatically,” he told the Reuters Global Climate and Alternative Energy Summit in a telephone interview.
“This is valid across all the scenarios I have seen,” said Edenhofer, who is also chief economist of the Potsdam Institute for Climate Impact Research. He gave no precise figures for the needed rise.
Renewable energies dominated by biomass -- such as firewood -- and including wind, hydro, solar and tidal power made up 13 percent of world energy demand in 2006, according to the International Energy Agency. Fossil fuels make up about 81 percent and nuclear power the other six.
The renewables report, by the U.N.’s Nobel Prize-winning Intergovernmental Panel on Climate Change (IPCC), is to be released in December 2010, a year after a new U.N. climate pact is due to be agreed in December in Copenhagen.
To cut reliance on fossil fuels, options include renewable energies, boosting nuclear power, seeking to improve energy efficiency or capturing and burying emissions of carbon dioxide, the main greenhouse gas released by burning fossil fuels.
“In most of these scenarios renewables play an important role even if you make nuclear and CCS (carbon capture and storage) a large part of your portfolio,” Edenhofer said.
Major economies, led by top greenhouse emitters China and the United States, agreed at a summit in Italy in July to try to limit world temperature rises to 2 Celsius over pre-industrial times. The European Union says 2 Celsius is a threshold for “dangerous” change.
Edenhofer said that the world had stalled in the past decade in sharpening policies to combat climate change, after agreeing the U.N.’s Kyoto Protocol in 1997 that limits greenhouse gas emissions by all developed nations except the United States.
“Basically we lost the last 10 years implementing climate policy, and now it becomes more and more complicated to achieve the 2 Celsius target, even with a massive increase of renewables,” he said.
Authors of the special report on renewable energies held a meeting in Oslo last week. Edenhofer is also working on a longer-term IPCC report into ways and costs of combating climate change and curbing feared impacts such as rising sea levels, more desertification, wildfires, droughts and floods.
Edenhofer declined to predict the overall conclusions of the renewables report, which will look at issues such as prospects for each technology, and how far they can be expanded and integrated into the fossil-fuel dominated energy system.