U.N. Draft Report Lists Unchecked Emissions’ Risks

http://www.nytimes.com/2014/08/27/science/earth/greenhouse-gas-emissions-are-growing-and-growing-more-dangerous-draft-of-un-report-says.html?partner=MYWAY&ei=5065

By JUSTIN GILLISAUG. 26, 2014

Runaway growth in the emission of greenhouse gases is swamping all political efforts to deal with the problem, raising the risk of “severe, pervasive and irreversible impacts” over the coming decades, according to a draft of a major new United Nations report.

Global warming is already cutting grain production by several percentage points, the report found, and that could grow much worse if emissions continue unchecked. Higher seas, devastating heat waves, torrential rain and other climate extremes are also being felt around the world as a result of human-produced emissions, the draft report said, and those problems are likely to intensify unless the gases are brought under control.

The world may already be nearing a temperature at which the loss of the vast ice sheet covering Greenland would become inevitable, the report said. The actual melting would then take centuries, but it would be unstoppable and could result in a sea level rise of 23 feet, with additional increases from other sources like melting Antarctic ice, potentially flooding the world’s major cities.

•••••

The report found that companies and governments had identified reserves of these fuels at least four times larger than could safely be burned if global warming is to be kept to a tolerable level.

That means if society wants to limit the risks to future generations, it must find the discipline to leave a vast majority of these valuable fuels in the ground, the report said.

•••••

From 1970 to 2000, global emissions of greenhouse gases grew at 1.3 percent a year. But from 2000 to 2010, that rate jumped to 2.2 percent a year, the report found, and the pace seems to be accelerating further in this decade.

A major part of the jump was caused by industrialization in China, which now accounts for half the world’s coal use. Those emissions are being incurred in large part to produce goods for consumption in the West.

•••••

President Obama, using his executive authority under the Clean Air Act, is seeking to impose national limits on emissions of greenhouse gases, but he faces profound legal and political challenges as he seeks to put his policy into effect before leaving office in early 2017.

The draft report found that past emissions, and the failure to heed scientific warnings about the risks, have made large-scale climatic shifts inevitable. But lowering emissions would still slow the expected pace of change, the report said, providing critical decades for human society and the natural world to adapt.