The Globe and Mail reports in its Thursday edition U.S. President Barack Obama and Chinese President Xi Jinping have raised the stakes in the battle over global climate policy. The Globe's Shawn McCarthy writes that in a deal signed Wednesday in Beijing, the two leaders agreed to make greater efforts to rein in greenhouse gas emissions. The announcement is expected to generate momentum as nations aim for an international agreement next year in Paris. China committed to slowing the rise of GHG emissions and stabilizing them by 2030. Mr. Obama pledged the United States would reduce its emissions by 26 per cent from 2005 levels by 2025. This raises significant challenges heading into an election year for Stephen Harper, who has linked Canada's actions on climate with those of the U.S. "Alignment with the U.S. just got a lot tougher and more complex," says David McLaughlin, former president of the National Roundtable on the Environment and Economy. Five years ago, the Prime Minister pledged Canada would reduce its emissions by 17 per cent from 2005 levels by 2020, a target equal to that adopted by Mr. Obama. Canada will fall short without aggressive new action, including regulations on the oil sands.