Climate pledges not enough to limit warming

Cooling towers of Czech coal-fired power plant Prunerov II are seen in Prunerov, near the northern Czech town of Chomutov, January 18, 2010.

LONDON (Reuters) - Carbon dioxide emissions in 2020 could be 5 billion to 9 billion tonnes above what is needed to limit global warming to 2 degrees Celsius, a United Nations Environment Programme (UNEP) report on Tuesday showed.

The report, prepared by UNEP, the European Climate Foundation and the National Institute of Ecology in Mexico, studied a range of estimates to assess whether current pledges for emissions cuts are enough to limit the worst effects of climate change.

"There is still a gap even to meet the minimum objectives which were agreed in Copenhagen," Achim Steiner, UNEP's executive director, said at a news conference in London.

The Copenhagen Accord climate deal reached last year agreed that deep cuts in global emissions were required to keep an increase in global temperature below 2 degrees Celsius.

The accord also called for an assessment to consider strengthening the long-term goal, including limiting temperature rises to 1.5 degrees.

However, in order to reach a 1.5 degree target, emissions after 2020 would have to fall by 4 to 5 percent a year, the report said.

Since December 2009, 140 countries have associated themselves with the Copenhagen Accord and 85 of these have pledged to cut their emissions or limit their growth up to 2020.

A U.N. climate summit in Cancun, Mexico, next week will strive to build on these pledges and move toward clinching a legally binding deal.

MIND THE GAP

Studies show that emission levels of around 44 billion tonnes of carbon dioxide equivalent in 2020 would probably limit global warming to 2 degrees Celsius, the report said.

If nothing is done to limit emissions, they could reach 56 billion tonnes in 2020, it estimated.

If only the weakest pledges were implemented in a lenient way, emissions could be lowered slightly to 53 billion tonnes, leaving a gap of 9 billion tonnes, the report said.

In the best case, if countries were to make more ambitious pledges, the figure could reach 49 billion tonnes, reducing the gap to 5 billion tonnes.

This is almost equal to annual global emissions from the world's cars, buses and transport in 2005 and almost 60 percent of the way toward reaching the 2 degree target.

"If we don't close the (5-9 billion tonne) gap, temperatures could rise roughly 2.5 to 5 degrees by the end of the century," said Joseph Alcamo, UNEP's chief scientist.

This could lead to sea level rises from melting ice caps and more extreme weather events like droughts and floods.

"If we do nothing at all, the range goes up to around 7 degrees as a global average above pre-industrial levels," added Jason Lowe at the UK Met Office's Hadley Center.

To prevent this, the U.N. summit in Cancun next week should make the promises made in Copenhagen more binding and ambitious and ensure strict rules for land use, forestry and surplus emissions units, the report said.

(Reporting by Nina Chestney; editing by Keiron Henderson)