The latest report
by the Intergovernmental Panel on Climate Change
(IPCC) shows that global emissions of greenhouse gases
have risen to unprecedented levels, despite a growing number of policies to reduce climate change. Nevertheless, a wide array of technological measures and behavioral changes could limit the increase in global mean temperature to two degrees Celsius above pre-industrial levels.
The report finds, however, that only major institutional and technological change will give a better-than-even chance that global warming
will not exceed this threshold
. Scenarios show that limiting the increase in global mean temperature to two degrees Celsius would mean 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
could require removing carbon dioxide from the atmosphere.
“Many different pathways lead to a future within the boundaries set by the two degrees Celsius goal,” said Ottmar Edenhofer, co-chair of the IPCC’s Working Group III, which produced the report. “All of these require substantial investments. Avoiding further delays in mitigation and making use of a broad variety of technologies can limit the associated costs.”