Mark Twain once quipped that everybody complains about the weather, but nobody does anything about it.

The US-China Climate Change Agreement may prove the old sage wrong. When the presidents of the world's two largest economies, which also happen to be the planet's two most polluting nations, agree that something has to be done about the climate, things could really get done, or so the experts say.

Jake Schmidt, director of International Programs at the Natural Resources Defense Council (NRDC), said that in all the years he has been working on the issue, he is now starting to see things change in profound ways.

Most significantly, he said, is the shift in perception that countries like China aren't doing anything on climate change?- "a relic of the debate almost two decades ago?- to a new reality?- that China is taking serious action and is clearly on the brink of even more major action", he wrote on his NRDC blog.

On the heels of the US-China Climate Change agreement, China's State Council issued a plan that included a long list of targets to modernize its energy structure.

China, which still relies on coal for 66 percent of its primary energy and 80 percent of its electricity, would hold its annual coal consumption below 4.2 billion tons until 2020, 16.3 percent more than the 3.6 billion tons burned last year, according to the plan.

Heavy responsibility is placed on regions around Beijing, the Yangtze River Delta and the Pearl River Delta, the three biggest city clusters, nudging them to wean off too much coal-burning.

In a speech at the Brookings Institution last month, Schmidt said peaking China's use of coal in the next five years seemed like an increasingly achievable goal.

"China's coal consumption in the first three quarters of 2014 was 1-2 percent lower than the same period in 2013," he said, "the first time coal consumption has fallen this century, even as its GDP continued to grow at 7.4 percent."

According to the plan, the share of non-fossil fuels in the total primary energy mix will rise to 15 percent by 2020 from 9.8 percent in 2013 and reach 20 percent by 2030.

Construction of new nuclear power plants in eastern coastal areas will begin once feasibility studies are completed. Combined with increased capacity of hydro-, wind and solar power, energy self-sufficiency will be boosted to around 85 percent.

In 2013, more new clean energy sources were added to China's grid than sources powered by fossil fuels for the first time in history, another trend that experts point to as encouraging.

The Three Gorges Dam alone produces 22 gigawatts of power, and China hopes to reach 1,000 gigawatts from such clean energy sources by 2030.

China is also a major importer of coal, oil, natural gas and uranium. Nearly 60 percent of oil and more than 30 percent of natural gas currently rely on imports.

China used 21.5 percent of global energy and generated 12.3 percent of the world's GDP. "Energy consumption per unit of GDP is very high," said Li Yizhong, president of China Federation of Industrial Economics, who called the plan's targets "pragmatic and obligatory".

Schmidt said China also has begun to implement new tools to take air pollution head-on, including more transparency and more meaningful fines on polluters.

The other good thing about the US-China agreement is the leadership role it provides. The 28 nations of the European Union have agreed to cut greenhouse pollution to 40 percent below 1990 levels by 2030.

Scientific American points out, however, that three major polluters have slipped backwards in their efforts. Australia's pollution spiked after it repealed its carbon tax; Canada has changed its mind about its prior agreement to the international global warming agreement; and Japan's air pollution has ballooned after it went back to burning more gas and coal to compensate for the nuclear power plants it took off line in the wake of the Fukushima disaster.

The experts agree that the road ahead will require tough measures and persistence. "We're nowhere near the world we need to be in to achieve our most ambitious climate goals," said Valerie Karplus, director of the Tsinghua-MIT China Energy and Climate Project. "We need to recognize that reality and think where do we go from here."

Schmidt remains upbeat. "We are confident that China can meet these coal consumption-control and CO2 objectives as it continues to develop its economy in a more balanced way," he said, "serving as a model for other countries to develop in a more climate-friendly way."

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