Climate change warning: Greenland once melted and raised the ocean 5 feet.

OTTAWA — On the same day Canadian tariffs on $28 billion worth of U.S. imports came into effect, Prime Minister Mark Carney said he doesn’t believe in escalating the trade conflict. “That’s not constructive,” said Carney, during a video address released on Tuesday. “But our tariffs are necessary protect our workers, protect our companies, and our communities.” Carney said his government can’t allow American goods into Canada tariff-free, while the U.S. charges Canadian companies to export. Canada’s latest round of tariffs against the U.S. is in response to U.S. President Donald Trump...