Plans by around 150 countries to cut greenhouse gas emissions are not enough to limit a rise in global temperatures to 2C, the United Nations (UN) said on Friday (6 November). Greenhouse gas emissions in 2030 could still be up to 12 billion tonnes more than the level needed to keep global warming within 2C this century, a UN report said.

The sixth annual UN Environment Programme (UNEP) report analysed the impact of countries' climate policies and emissions pledges ahead of a global climate deal to be signed in Paris next month and whether they are enough to limit global temperature increases to within 2C this century, a threshold seen by scientists as avoiding the most devastating effects of climate change.

"We have set a target that is called the "two degrees centigrade target", and this is because if we stay on a pathway that doesn't allow the global temperatures to exceed that, then we know in a sense that we are safe. What we have on the table today is not enough, but we know how to fill the gap, which is why the report form UNEP talks about the emissions gap report, and that would come through energy efficiency, the way that we build renewable energy, moving to a low-carbon economy, in fact the way we run our society, the way we consume," UNEP chief scientist Jacqueline McGlade said in Geneva.

To stay within the 2C limit, global emissions levels should not exceed 42bn tonnes in 2030. However, even if all countries' conditional and unconditional plans for emission cuts are implemented fully, emissions could rise to 54bn tonnes in 2030, leaving a gap of 12bn tonnes, the report said.

The plans, known as Intended Nationally Determined Contributions (INDCs), will be the building blocks for a UN deal expected at a summit set to take place in Paris from 30 November to 11 December to fight global warming in the years from 2020.

Poorer nations, which might be the most vulnerable to climate change, have said negotiators should not abandon hope of limiting temperature rises to below 1.5C, even if targets on the table in Paris are less ambitious.