On November 11, representatives from nearly 200 countries will gather in Warsaw for the 19th session of the Conference of the Parties to the United Nations Framework Convention on Climate Change (UNFCCC). Discussion will focus on a global deal to fight climate change that would be agreed to in 2015 and implemented in 2020. A report released last Thursday by the PBL Netherlands Environmental Assessment Agency could complicate these talks as it addresses who is most to blame for global warming—a key discussion point in UN climate negotiations. According to the study, from 1850 to 2010, developing countries—including China and other emerging economies—accounted for 48 percent of cumulative emissions, but by 2020, that number is likely to reach 51 percent. The report indicated that the biggest emitters since 1850 have been the United States, China, the European Union, and Russia. China, however, has argued that it bears less responsibility as its per capita emissions are much lower than those of other developed nations. For the full story, see http://www.theguardian.com/environment/2013/nov/01/china-half-global-carbon-emissions. For the Netherlands Environmental Assessment Agency report, see http://www.pbl.nl/sites/default/files/cms/publicaties/pbl-2013-trends-in-global-co2-emissions-2013-report-1148.pdf.