Governments Agree U.N. Study of Tough Climate Limit, Despite Doubts

* IPCC launches study of 1.5 degree limit, due in 2018

* Some scientists doubt limit feasible, with rising temperatures

Governments gave the green light on Thursday for a U.N. scientific study on how to meet an ambitious global warming target, despite growing worries by some scientists that the goal may be unrealistic.

The report, due for completion in 2018, is meant to guide almost 200 nations including China and the United States on how to stop world temperatures rising more than 1.5 degrees Celsius (2.7 Fahrenheit).

But some scientists say the 1.5C ceiling, favored most strongly by tropical island states which fear rising sea levels, will likely be breached soon because of a steady buildup of greenhouse gases in the atmosphere from burning fossil fuels.

And world leaders have only signed up for a less ambitious plan - their promise in Paris last December to limit global warming to "well below" 2C above pre-industrial times, while "pursuing efforts" for 1.5 degrees.

The study, approved by government officials and scientists at the U.N.'s Intergovernmental Panel on Climate Change (IPCC) in Bangkok on Thursday, will look at ways to meet the tougher target.

The paper, due for completion in 2018, will also look at the likely impacts of a 1.5C rise on the planet, from tropical coral reefs to Greenland's ice, and try to ensure that policies to limit warming also reduce poverty.
...
The IPCC report "should not be mis-interpreted as a sign that the industrialized countries are now willing to mitigate at the level that would be needed" to limit temperature rises to 1.5C or even 2C, he said.

And last week, two scientists wrote in the journal Science that a 1.5C limit would have to rely too heavily on so-called "negative emissions" to extract carbon dioxide from the air with technologies that do not yet exist.

Read more at Governments Agree U.N. Study of Tough Climate Limit, Despite Doubts