The leaders of the world’s two largest economies will announce new climate regulations today. For the first time, China will implement a national cap-and-trade system that will put a price on emitting carbon into the environment starting in 2017.

“China’s government, they understand that now they are the second largest economy in the world,” says Yang Fuqiang, senior advisor at the Natural Resource Development Council in Beijing. “Now they have to do something.”

Yang hopes today’s announcement will persuade other developing countries to follow China’s lead. Pricing and regulating greenhouse gas emissions is a big job that involves every aspect of the economy.

UCLA Law Professor Alex Wang predicts some polluters in China will try and cheat to get around the rules. But he’s optimistic, because the cap-and-trade system will be under the jurisdiction of one of China’s most powerful agencies, the National Development and Reform Commission. The other reason he’s hopeful: today’s very public support from President Xi Jinping.

“A high-level announcement like this helps on the implementation side,” says Wang. “It gives anyone who’s supportive of the idea in China the political support to run with things.”

China has experience running carbon markets in seven pilot programs around the country. The idea for the cap-and-trade system was developed in America, but when President Obama tried to get Congress to enact the system in his first term, it died in the Senate.

The reason: lawmakers from both parties feared it could threaten America’s economic competition with China.