The United States and China made a big splash this past month with the announcement of an important climate agreement between the two superpowers. President Obama and Chinese President Xi Jinping jointly pledged November 11 in Beijing to make significant CO2 reductions in the next two decades. The United States will reduce its net greenhouse gas emissions by 26 to 28% below 2005 levels by 2025, accelerating the pace of reductions already planned by 2020. China will peak its CO2 emissions no later than 2030, by which point the country will obtain 20% of its energy supply from non-fossil fuel sources. China’s commitment marks the first time the country has pledged to stop its rapidly increasing emissions; the nation has previously resisted calls for reductions, saying that as a developing country, the pollution increases are necessary for its growth. This agreement preceded a November 16 communiqué by G20 leaders to focus their policies and investments on cleaner and renewable energy sources with the goal of mitigating climate change. The next step began December 1 at the United Nations Framework Convention on Climate Change conference in Lima, Peru.