The climate breakthrough in Beijing gives the world a fighting chance - The A-List President Barack Obama and President Xi Jinping at a joint press conference on November 12 (Greg Baker/AFP/Getty Images) Today's US-China joint announcement on climate change and energy is the most important advance on the climate change agenda in many years. While the full ramifications will only be known at the climate summit in Paris in December 2015, the two largest C02 emitters have finally spoken, and most importantly, they've spoken together. What they've said gives the world a fighting chance - and no doubt the last one - for climate safety. The situation is stark. While the world's governments agreed back in 2009 that we need to keep global warming below 2 degrees Celsius (relative to the pre-industrial era), in order to avoid massive damages from droughts, floods, extreme heat waves, and rising ocean levels, the brutal fact remains that the world is on course for a catastrophic rise of some 4 to 6 degrees by the end of the century. To avoid catastrophe, and stay below the 2 degree upper limit, CO2 emissions from energy use need to fall very sharply by mid century, and to reach net-zero emissions ("decarbonization") by around 2070. In short, the world will need to get almost entirely out of the fossil fuel business in the next half century or so, except for what can be continued safely with the use of carbon capture and storage (CCS). Such a deep transformation is feasible through a combination of three main steps: massive energy efficiency; a pervasive shift to low-carbon and zero-carbon electricity (notably wind, solar, geothermal, hydro, nuclear, and CCS); and the electrification of all vehicle transport and of heating and ventilation in residential and commercial buildings. Two kinds of breakthrough First, China, the world's largest emitter by far in absolute terms (roughly 28 per cent of the world's CO2 emissions in 2014) has agreed a clear target to reach a peak of CO2 emissions no later than 2030, with the intention of trying to peak earlier than 2030. The US's failure to act decisively on its own emissions for two decades has long been defended by the Senate on the basis that the US should act only if China does as well. That bottleneck and excuse is ending. Second, the US-China agreement has the necessary three components for deep transformation by mid-century. The agreement calls for: 1) short-term commitments by both countries to 2030 2) deep decarbonization by mid-century, with the US re-stating the goal of an 80 per cent CO2 reduction by the US by 2050 3) a massive scale-up of research, development, demonstration, and diffusion (RDD&D) of low-carbon energy technologies. Specifically, China and the US committed to joint R&D in building efficiency, clean vehicles CCS, smart cities, and other areas. What chance of success? An announcement is just an announcement, of course. There are many crucial details and years of action that will make the difference between mere rhetoric and true climate safety. Both countries need to show how they intend to reach not only the short-term 2025-2030 goals, but also the mid-century deep decarbonization that is really the essence of the climate challenge. Short-term commitments are fine, but can easily be an illusion as well, with short-term steps of little long-term significance, unless the short-run measures are part of a long-term path out of carbon energy. The US and China have yet to put their cards on the table on how they intend to achieve deep decarbonization. Still, the G2 has now spoken, and together with the EU, which made its own bold announcements just recently, the world's three biggest economies and largest emitters are now on course for a serious agreement in Paris. Others will join. The three-part structure of today's announcement can serve as the right blueprint for a serious and historic global deal in Paris. And the arithmetic is clear: if we fail in Paris, we will fail to stay below 2 degrees. Paris is the last chance. Not surprisingly, the incoming Republican Senate majority leader Mitch McConnell piped up immediately that he and his colleagues would oppose the deal. No doubt they will try. Yet my guess is that Mr McConnell and his buddies are soon going to learn a lesson in real democracy. While the fossil fuel lobby may have helped finance the Republican victories last week, the US public cares about its own survival and the world that their children will soon inherit. The public has tasted reality with Superstorm Sandy, with California's record-breaking droughts, unprecedented heat waves, and repeated flooding of the eastern seaboard. The Koch brothers may have bought some 44,000 paid ads this fall to help put favoured coal and oil candidates over the top, but they did not buy the souls of the American people, who by a large majority will be gratified today by the announcements from Beijing. The climate is heating up but so too are the climate negotiations. Today's announcement is a major step forward for the vast majority of humanity who are seeking a safer planet.