In a stunning historic climate change deal, President Obama and Chinese President Xi Jinping announced on Wednesday both countries will curb their greenhouse gas emissions over the next two decades.

Under the agreement, the United States agreed to cut its carbon emissions by 26-28 percent before the year 2025, and China agreed 2030 would be its peak year for emissions, and would aim to get 20 percent of its energy from zero-carbon emission sources by the same year. This marks the first time China has agreed to maximum emissions.

"As the world's two largest economies, energy consumers and emitters of greenhouse gases, we have a special responsibility to lead the global effort against climate change," Obama said in a joint press conference with Xi. Obama said he hoped the announcement would spur other nations to tackle climate change.

"We hope to encourage all major economies to be ambitious -- all countries, developing and developed -- to work across some of the old divides, so we can conclude a strong global climate agreement next year," Obama said.

The accord between China and the U.S., the world's largest gas emitters, is largely symbolic, but its announcement has eroded the divide between rich and poor nations over their respective responsibilities for tackling climate change that has prevented a global agreement deal for years. Almost 200 nations have agreed to work out a U.N. climate agreement at a summit in Paris in late 2015.

"This announcement from the U.S. and China to reduce greenhouse emissions is a signal that the two largest climate polluters are moving on climate change. But comparing their pledges to what science says is needed to avoid climate catastrophe, a global cut in greenhouse gas emissions by 80 percent from 1990 levels by mid-century, these economic powerhouses are not taking that threat seriously enough," Janet Redman, climate policy program director at the Institute for Policy Studies, told the Institute for Public Accuracy.

The head of the U.N. panel of climate scientists, Rajendra Pachauri, told Reuters the deal was "heartening" but falls short of the action needed to avert the worst impacts of global warming.

"The deal brokered between China and the U.S. on greenhouse gas emissions is significant but only because our expectations are so low," Daphne Wysham, climate policy fellow at the Center for Sustainable Economy, told the Institute for Public Accuracy. "The three primary flaws in this agreement: 1) It kicks the can down the road to 2030, when climate science tells us China must peak its greenhouse gas emissions by 2020; 2) The U.S. can continue to export the equivalent of five times the carbon contained in the Keystone XL pipeline annually in new, heavily subsidized coal, oil and gas shipments without taking responsibility for these greenhouse gas emissions; and 3) China's plan to expand its fleet of nuclear power plants is a dangerous and expensive response to the climate crisis, ignoring the lessons of Fukushima."