Global 2-Degree Temperature Limit Lives On, but Concerns Mount That Goal Is Unrealistic

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By Dean Scott

Dec. 12—As two weeks of talks toward a 2015 global climate change accord neared their end Dec. 12, environmental groups continued to push negotiators to retain language pledging more than 190 nations to a goal of keeping global temperatures from rising more than 2 degrees Celsius (3.6 degrees Fahrenheit) from preindustrial levels.

The goal, first outlined in the 2009 Copenhagen climate summit, does not bind the countries to cut greenhouse gas emissions to whatever level is needed to keep the temperature increase under the 2-degree C rise.

But for many advocates of climate action, including environmental groups and climate scientists, the 2-degree marker is essential to retain as a guidepost and for measuring progress by developed and developing nations in cutting greenhouse gas emissions.

As the two weeks of talks spilled over into the weekend past their scheduled Dec. 12 end, the 2-degree goal is sprinkled liberally throughout negotiating texts that are expected to be produced from talks here and which will guide negotiators in finalizing the global greenhouse gas accord a year from now in Paris.

2-Degree Target Repeatedly Mentioned

For example, the 2-degree C goal is mentioned (Page 16, Line 813) in draft “Elements” Text in reference to climate finance that developed countries are to provide developing nations already being hit by rising sea level and other climate impacts.

The U.S., European Union and other industrialized economies are to provide $100 billion a year beginning in 2020 in climate aid “as a means to meet the goal of staying below the 2 degrees temperature increase and to achieve the transformation,” the finance section said.

Alden Meyer, who follows the negotiations for the Union of Concerned Scientists, said as of late Dec. 12, the 2-degree pledge was still referenced repeatedly in other sections, including the preamble—known as “preambular text”—as well as in other sections mentioning a general 2-degree C “goal” and as a separate long-term mitigation goal.

Other language in the texts provides insight into how the world would try to keep temperatures under that 2-degree C rise, including a call for phasing out fossil fuels by 2050 and a separate pledge for net zero greenhouse gas emissions worldwide by 2100. Both were in the texts as of late Dec. 12

That would mean any new greenhouse gas emissions would have to be offset by efforts such as tree plantings and technologies, such as those that capture and store carbon dioxide emitted by coal-fired power plants.

Should Goal Be Further Strengthened?

The 2-degree limit essentially became a goal of negotiators at the Copenhagen climate summit. The Copenhagen Accord included language that noted “the scientific view that the increase in global temperatures [should remain] below 2 degrees,” and said parties would work to “enhance long-term cooperative action to combat climate change.”

With negotiators now approaching the last 12 months of talks before they are to finalize the Paris 2015 accord, many environmental groups have vowed to strengthen the goal or at least ensure it is not dropped in the negotiations in Paris. Some environmental groups and scientists want a more stringent goal—a pledge to keep temperatures below a rise of 1.5 degrees C, for example.

2 C Degree-Rise by 2046?

But many scientists say that without massive action to cut emissions, temperatures will soar past the current 2-degree limit just 30 years from now, on a trajectory of at least another 2-degree C rise—and perhaps even more than that— through 2100.

“We will be at that 2-degree ceiling if we continue with a business as usual scenario” in which emissions continue their rapid rise to mid-century, Peter Frumhoff, chief scientist for the Climate Campaign, told Bloomberg BNA.

Frumhoff noted that global temperatures have already risen about 0.85 C since preindustrial times, meaning there is less than 1.2 C of “room” for temperatures to increase before the world hits the 2 C ceiling.

Also, global greenhouse gas emissions have been increasing at an enormous rate in recent decades to a point where capping global emissions is unrealistic any time soon.

By the time former NASA Goddard Institute for Space Studies scientist James Hansen first highlighted for Congress concerns over global warming in 1988, it had taken the world more than 200 years to emit the 737 gigatons that had amassed in the atmosphere between 1751 and 1987, Frumhoff said.

Nations have emitted nearly that same amount—743 gigatons—in just the last 25 or so years, from 1988 to 2014, he said.

To contact the reporter on this story: Dean Scott in Lima at

To contact the editor responsible for this story: Larry Pearl at


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