The offers that countries have already made to reduce their carbon emissions are only a 'few billion tonnes' short of the total cuts needed to hot the target of capping the rise in global temperatures, Lord Stern said in Copenhagen as the climate change conference got underway.

Countries meeting at the United Nations climate change conference may be closer than some observers realise to agreeing the emissions cuts required to give the world a reasonable chance of avoiding global warming of more than 2˚C above pre-industrial levels, he said.

Lord Stern, the economist and climate change expert, wrote an analysis of national proposals for annual emissions reductions for the United National Environment Programme (UNEP).

The research estimates that in order to have a 50/50 chance of avoiding a rise in global temperature of more than 2˚C – the level scientists believe will trigger environmental catastrophe - annual emissions of greenhouse gases must be no more than 44 billion tonnes by 2020.

The analysis shows that the gap between this target and the most ambitious cuts proposed by countries over the past months and weeks is about 2 billion tonnes, with a range of 1 to 5 billion tonnes.

If the overall target 44 billion tonnes is exceeded in 2020, it is likely to be more difficult and costly to reach the goal as much stronger action would be required in decades afterwards, it found.

'No one should be under any illusion,' Lord Stern said at the launch of the report: 'Reaching the target to cut annual emissions to 44 billion tonnes in 2020, by bridging the remaining gap of a few billion tonnes, will require governments over the next two weeks and over the next few years to match words with deeds and ambition with action.'

'If they do, we could embark on the most dynamic and creative period of the world's economic history, a new energy and industrial revolution.'

The report said that gap could be filled during negotiations in Copenhagen by combining several additional actions including:

• Developed countries increasing their high intentions;
• Key developing countries offering more than their existing proposals, particularly in the context of serious international support for the developing world, covering both adaptation and mitigation;
• Additional reductions from deforestation and other sources, and in particular international commitments to support and enhance the national efforts of countries such as Brazil and Indonesia; and
• Incorporating international emissions from aviation and shipping in order to deliver additional emissions reductions.

Achim Steiner, UNEP's Executive Director said: 'Having a reasonable chance of limiting a global temperature rise to no more than 2˚C can, with clearly designed policies applied consistently across countries and industries, be cost effectively met and can also set the stage for a low-carbon, resource-efficient 21st century green economy — that is the central message.'

The report comes a week after Lord Stern used a report, published by the London School of Economics' Grantham Research Institute on Climate Change and the Environment, which he chairs, to say that rich countries must provide as much as $200bn a year to poorer countries to help them adapt to and mitigate climate change.

Related links

Bridging the emissions reduction gap in Copenhagen, United Nations Environment Programme 06 December 2009

The Grantham Research Institute on Climate Change and the Environment, The London School of Economics and Political Science