The technology to prevent catastrophic global warming exists, but the world needs to act quickly, scientists and politicians agreed yesterday at a United Nations conference.

Restricting temperature rises to 2.4C (4.3F) globally by 2050 will require carbon emissions to peak by 2015, the Intergov-ernmental Panel on Climate Change (IPCC) declared.

Its report on the potential for mitigating the effects of climate change and the costs involved, Summary for Policymakers, was agreed by delegations from more than 120 nations, including China, India and the US.

It identified a maximum 2 to 2.4C rise in temperatures as costing 0.12 of annual world-wide gross domestic income but governments must sign up to it almost immediately.

Current emission levels mean that a 1C rise over preindustrial levels is inevitable and limiting the increase to 2C is regarded as optimistic.

A scenario allowing for emissions to peak in 2020 would lead to a projected temperature rise of between 2.4 and 2.8C, while a peak by 2030 would result in a rise of between 2.8 and 3.2C. Inaction could cause devastating climate change with 6C increases in 100 years.

The report was welcomed by environmentalists as “a road map” to saving the planet. The Royal Society said: “This report offers hope for the future. We cannot undo the harm that has already been done . . . however, it provides us with a realistic way forward.”

The European Union intends to use the IPCC’s conclusions to demand a successor to the Kyoto treaty at the UN ministerial conference in December.

However, even a 2C rise by the middle of the century would mean an extra 2 billion people short of water, and the extinction of between 20 and 30 per cent of wildlife species.

The IPCC said that it wants every country to be subject to carbon trading schemes, in which companies pay for the carbon they emit. Carbon capture and storage, in which carbon is caught as it is produced and stored in rock formations under the sea, was high-lighted as a key technology.

Similarly, reduced dependence on fossil fuels through the expansion of the nuclear industry and renewable energy were regarded as important factors.

The IPCC suggested increasing nuclear capacity from 16 to 18 per cent of world energy supply and increasing renewables such as wind, solar and tidal power from 18 per cent to between 30 and 35 per cent.

Each sector of society must play its role, according to the report. Farmers are expected to improve land management so that the soil absorbs more carbon. The transport sector was urged to bring in more hybrid and fuel-efficient vehicles.

A reduction in deforestation was cited as an important route to cutting carbon emissions.

Times Recommends

• What makes the perfect mum?
• To keep me stress-free, no more awareness days, please
• What do lottery winners buy?