When President Obama flew to Ottawa, Canada, on Wednesday to meet with Canadian Prime Minister Justin Trudeau and Mexican President Enrique Peña Nieto, promoting their climate-change policies was near the top of the agenda. “The Paris Agreement was a turning point for our planet,” the leaders’ joint statement said, referring to the climate pact signed with fanfare in April by nearly 200 nations. “North America has the capacity, resources and the moral imperative to show strong leadership building on the Paris Agreement and promoting its early entry into force.”