* 20-65 pct of adverse climate impacts could be avoided
* Emissions need to peak in 2016, fall by 5 pct/yr to 2050
By Nina Chestney
LONDON, Jan 13 (Reuters) - The world could avoid much of the damaging effects of climate change this century if greenhouse gas emissions are curbed more sharply, research showed on Sunday.
The study, published in the journal Nature Climate Change, is the first comprehensive assessment of the benefits of cutting emissions to keep the global temperature rise to within 2 degrees Celsius by 2100, a level which scientists say would avoid the worst effects of climate change.
It found 20 to 65 percent of the adverse impacts by the end of this century could be avoided.
"Our research clearly identifies the benefits of reducing greenhouse gas emissions - less severe impacts on flooding and crops are two areas of particular benefit," said Nigel Arnell, director of the University of Reading's Walker Institute, which led the study.
In 2010, governments agreed to curb emissions to keep temperatures from rising above 2 degrees C, but current emissions reduction targets are on track to lead to a temperature rise of 4 degrees or more by 2100.
The World Bank has warned more extreme weather will become the "new normal" if global temperature rises by 4 degrees.
Extreme heatwaves could devastate areas from the Middle East to the United States, while sea levels could rise by up to 91 cm (3 feet), flooding cities in countries such as Vietnam and Bangladesh, the bank has said.
The latest research involved scientists from British institutions including the University of Reading, the Met Office Hadley Centre and the Tyndall Centre for Climate Change, as well as Germany's Potsdam Institute for Climate Impact Research.
It examined a range of emissions-cut scenarios and their impact on factors including flooding, drought, water availability and crop productivity. The strictest scenario kept global temperature rise to 2 degrees C with emissions peaking in 2016 and declining by 5 percent a year to 2050.
Adverse effects such as declining crop productivity and exposure to river flooding could be reduced by 40 to 65 percent by 2100 if warming is limited to 2 degrees, the study said.
Global average sea level rise could be reduced to 30cm (12 inches) by 2100, compared to 47-55cm (18-22 inches) if no action to cut emissions is taken, it said.
Some adverse climate impacts could also be delayed by many decades. The global productivity of spring wheat could drop by 20 percent by the 2050s, but the fall in yield could be delayed until 2100 if strict emissions curbs were enforced.
"Reducing greenhouse gas emissions won't avoid the impacts of climate change altogether of course, but our research shows it will buy time to make things like buildings, transport systems and agriculture more resilient to climate change," Arnell said.
About 190 nations are aiming to sign a deal by 2015 which will legally bind countries to make ambitious emissions cuts but it will not come into force until 2020.
U.N. climate negotiations in Qatar in December ended with little progress on emissions cuts.
"This research helps us quantify the benefits of limiting temperature rise to 2 degrees C and underlines why it's vital we stick with the U.N. climate change negotiations and secure a global legally binding deal by 2015," said Edward Davey, Britain's Secretary of State for Energy and Climate Change.
The study can be viewed at: http://dx.doi.org/10.1038/nclimate1793 (Reporting by Nina Chestney; Editing by Pravin Char)