* Policies not adequate to limit warming to 2 degrees
* Could widen emissions gap to 9 billion tonnes by 2020
By Nina Chestney
BONN, Germany, May 24 (Reuters) - Greenhouse gas emissions in 2020 could rise to nine billion tonnes above what is needed to limit global warming as some countries look set to miss their emissions cut targets, a report by three climate research groups said on Wednesday.
Countries have agreed that deep emissions cuts are needed to limit an increase in global average temperature to less than 2 degrees Celsius this century above pre-industrial levels, a threshold that scientists say is the minimum required to limit devastating climate effects like crop failure and melting glaciers.
They believe the 2 degree limit is only possible if emission levels are kept to around 44 billion tonnes of carbon dioxide equivalent in 2020.
The report by non-governmental organisation Climate Analytics, consultancy Ecofys and the Potsdam Institute for Climate Impact Research said many governments are not implementing policies to meet their emissions reduction pledges for 2020, and could increase rather than close the gap between real emissions and what is needed to limit warming,
Negotiators from over 180 nations are meeting in Bonn, Germany, until Friday, to work towards getting a new global climate pact signed by 2015 and to ensure ambitious emissions cuts are made after the Kyoto Protocol expires at the end of this year.
Procedural wrangling and a reluctance to raise ambitions to cut emissions due to economic constraints is threatening progress, however.
"It's clear that many governments are nowhere near putting in place the policies they have committed to, policies that are not enough to keep temperature rise to below 2 degrees," said Bill Hare, Director of Climate Analytics.
"We've already identified a major emissions gap and the action being taken is highly unlikely to shrink that gap - indeed it seems that the opposite is happening," he added.
The planet is heading to a temperature rise of at least 3.5 degrees, but that could be even more if 2020 pledges are not met, the report warned.
"There would be quite profound effects on developing countries," Hare told reporters at a briefing.
"And there would be a big impact on Europe with extensive heatwaves, water shortages and (...) health risks we have not seen before."
Even if governments adopted the most ambitious emissions cut pledges and used very strict accounting, the emissions gap would only shrink to 9 billion tonnes, the report said.
The forecast is at the high end of some previous estimates.
Last November, the United Nations' Environment Programme said emissions in 2020 could rise to between 6 billion and 11 billion tonnes above what is needed to limit global warming, depending on how stringently policies are implemented.
"Most of the policies we have analyzed are not yet concrete enough to be quantified, not yet implemented and/or not yet sufficiently ambitious to ensure countries achieve their pledge. This is a worrying trend," said Dr Niklas Höhne, Director of Energy and Climate Policy at Ecofys.
Some large emitters are not on track to meet their pledges.
Even though the United States expects to lower emissions in 2020, this is mainly due to the impact of economic downturn and a shift from carbon-heavy goal to cleaner natural gas.
"A significant gap of 384 (million tonnes) remains and it is unclear how the U.S. intends to close the remaining gap," the report said.
Brazil's deforestation rates are currently at a record low but if it adopts its proposed new forest code on Friday, it could reverse this trend.
"Scientific analysis shows that the code could increase its emissions gap substantially," the report said.
Mexico is only on track to achieve 12 percent of its pledged 30 percent emissions reduction by 2020, and it is still not clear whether Japan will cut carbon emissions from its electricity sector as its nuclear reactors have been shut following the Fukushima accident last year, it added. (Editing by Anthony Barker)