Renewable sources such as solar and wind could supply up to 80 per cent of the world’s energy by 2050 and play a significant role in fighting global warming, a top climate group claims.

But the UN Intergovernmental Panel on Climate Change said that to achieve that level, governments would have to do more to introduce policies that integrate renewables into existing power grids and promote their benefits in terms of reducing air pollution and improving public health.

Authors said the report concluded that the use of renewables is on the rise, their prices are declining and that with the right policies, they will be an important tool both in tackling climate change and helping poor countries use the likes of solar or wind to develop their economies in a sustainable fashion.

“The report shows that it is not the availability of the resource but the public policies that will either expand or constrain renewable energy development over the coming decades,” said Ramon Pichs, who co-chaired the group tasked with producing the report.

“Developing countries have an important stake in this future – this is where 1.4 billion people without access to electricity live yet also where some of the best conditions exist for renewable energy deployment.”

Governments endorsed the renewable report after a four-day meeting. The non-binding scientific policy document is to advise governments as they draw up policies and to help guide the private sector as it considers areas in which to invest.

Activists said Saudi Arabia and Qatar, two oil-rich states that do not have an interest in alternatives, successfully watered down the report’s language on the cost benefits of renewables – a charge the Saudis denied, saying they only were arguing to stick with the science.

Brazil, a major ethanol producer, opposed language on the negative effects of biofuels and hydro as well as the economic potential of other renewables.

The report reviewed bioenergy, solar energy, geothermal, hydropower, ocean energy and wind. It did not consider nuclear, so Mr Pachauri said the recent nuclear accident in Japan was not discussed nor did it have any impact on the report’s conclusions.

The IPCC has said swift, deep reductions in use of non-renewables are required to keep temperatures from rising more than two degrees Celsius above pre-industrial levels, which could trigger catastrophic climate impacts.