Commentary The Supreme Court of Canada ruled March 25 that the federal government is fully within its jurisdiction to impose a carbon tax on provinces, even if the duly elected governments of those provinces oppose the imposition of such a tax. Their rationale? The wisdom of Greta Thunberg. Judges aren’t scientists. They aren’t climate experts. Yet in this case the judges have acted like they are both. I’m surprised they didn’t quote Greta directly with a “how dare you” statement. In effect, that is what they have given us. What the court did was declare that global warming—a term even environmentalists weren’t using this winter in the Northern Hemisphere because we kept having cold snaps—causes harm beyond provincial boundaries. The court ruled that global warming is therefore a matter of national concern that allows the federal government to rely on its residual constitutional power, found in the “peace, order, and …