The most notable commitment, outlined in a joint statement by the leaders, is a plan to reduce potent methane emissions from the oil and gas industry by 40-45% below 2012 levels by 2025.
Yet their announcement also served as a broader reaffirmation of the cooperative spirit long shared between the countries -- strained in recent years -- that has moved forward significantly since Trudeau's election in October.
"The United States and Canada must and will play a leadership role internationally in the low carbon global economy over the coming decades," the two leaders said in a joint statement.
Under Trudeau's predecessor,
Trudeau, the moderate son of former Prime Minister Pierre Trudeau, made environmental issues a key part of his 2015 campaign and said that although he supported Keystone XL, he would not allow the debate over it to taint relations between the two countries.
In early November, less than three weeks after Trudeau won office, Obama announced that he was rejecting the pipeline. Soon after that, Trudeau traveled to the Paris climate talks to underscore Canada's commitment to addressing climate change.
The announcement Thursday was among the strongest evidence of that commitment. Canada and the U.S. said they "will work together to implement the historic Paris agreement, and commit to join and sign the agreement as soon as feasible."
They agreed to a broad set of plans, including working together to expand emission limits on vehicles, looking for ways to reduce airplane emissions and exploring putting a price on industrial carbon emissions.
The plan to reduce methane drew by far the most praise and criticism.
Though carbon dioxide poses greater climate risks over the long term, methane is far more potent in the short term, accounting for as much as 25% of the planet's current warming. The oil and gas industry is by far the largest emitter of methane, much of it through leaks in drilling and delivery systems.
The U.S. Environmental Protection Agency is already preparing to implement a rule that would reduce emissions on new and modified oil and gas wells. The proposed new policy would apply to existing facilities.
"This ultimately is such a common sense thing to focus on," Mark Brownstein, vice president for climate and energy at the
But the plan was criticized by the industry, which said it was already taking steps to reduce methane emissions.
"Additional regulations on methane by the administration could discourage the shale energy revolution that has helped America lead the world in reducing emissions while significantly lowering the costs of energy to consumers," Kyle Isakower, the vice president of regulatory and economic policy for the American Petroleum Institute, said in a written statement. "The administration is catering to environmental extremists at the expense of American consumers."
Some environmental groups said a better solution would be to reduce fossil fuels and hydraulic fracturing, a drilling method linked to methane leaks.
"In order to avert health and climate catastrophe, we must keep fossil fuels in the ground and begin investing immediately in a 100% clean, renewable energy future," said Wenonah Hauter, executive director of Food & Water Watch.
In the Arctic, where sea ice has been at record lows and the region faces increasing pressure from oil development and fishing, Obama and Trudeau announced plans to create "low-impact shipping corridors," prevent over-fishing, and expand on existing goals to protect "at least 17% of land areas and 10% of marine areas by 2020."
"If oil and gas development and exploration proceeds, activities must align with science-based standards between the two nations that ensure appropriate preparation for operating in Arctic conditions, including robust and effective well control and emergency response measures," the policy statement said.
Carter Roberts, the president and chief executive of the
At a news conference in the White House Rose Garden on Thursday, Obama referred to his trip to Alaska in August and to meetings about the Arctic to be held in Washington this fall.
"As the first U.S. president to visit the Arctic,"I saw how both of our nations are threatened by rising seas, melting permafrost, disappearing glaciers and sea ice, and so we are focusing on making sure the Paris agreement is fully implemented and we're working to double our investments in clean energy research and development," he said.
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