Greenhouse gases grow despite renewable energy efforts, says UN
Global emissions of greenhouse gases have risen to unprecedented levels despite renewable energy sources and a growing number of policies to reduce climate change. Emissions grew more quickly between 2000 and 2010 than in each of the three previous decades, according to a new report by the United Nation's Intergovernmental Panel on Climate Change (IPCC).
It would be possible, using a wide array of technological measures and changes in behavior, to limit the increase in global mean temperature to two degrees Celsius above pre-industrial levels, according to the Working Group III contribution to the IPCC’s Fifth Assessment Report. However, only major institutional and technological change will give a better than even chance that global warming will not exceed this threshold.
The report, titled “Climate Change 2014: Mitigation of Climate Change,” is the third of three Working Group reports, which, along with a Synthesis Report due in October 2014, constitute the IPCC’s Fifth Assessment Report on climate change. Working Group III is led by three co-chairs: Ottmar Edenhofer from Germany, Ramón Pichs-Madruga from Cuba, and Youba Sokona from Mali.
“Climate policies in line with the two degrees Celsius goal need to aim for substantial emission reductions,” Edenhofer said in a released statement. “There is a clear message from science: To avoid dangerous interference with the climate system, we need to move away from business as usual.”
Scenarios show that to have a likely chance of limiting the increase in global mean temperature to two degrees Celsius, means lowering global greenhouse gas emissions by 40 to 70 percent compared with 2010 by mid-century, and to near-zero by the end of this century. Ambitious mitigation may even require removing carbon dioxide from the atmosphere.
Scientific literature confirms that even less ambitious temperature goals would still require similar emissions reductions.
For the report, about 1,200 scenarios from scientific literature have been analyzed. These scenarios were generated by 31 modeling teams around the world to explore the economic, technological and institutional prerequisites and implications of mitigation pathways with different degrees of ambition.
Estimates of the economic costs of mitigation vary widely. In business-as-usual scenarios, consumption grows by 1.6 to 3 percent per year. Ambitious mitigation would reduce this growth by around 0.06 percentage points a year. However, the underlying estimates do not take into account economic benefits of reduced climate change.
“The core task of climate change mitigation is decoupling greenhouse gas emissions from the growth of economies and population,” Sokona said. “Through providing energy access and reducing local air pollution, many mitigation measures can contribute to sustainable development.”