TORONTO—The fossil fuel party has been great. Plentiful, low-cost hydrocarbons pulled humans out of the muck and into the 21st century. For many Canadians, life is grand—we fly on vacation, drink wine from Australia, and watch TVs made on the cheap in China in homes that are warm in winter and cool in summer. Our ability to export abundant fossil fuel resources means Canadians doubly benefit. Nobody in their right minds wants the party to end— but end it must.