The COP26 global climate summit is, by design, about bargaining and voluntary steps, not mandates and penalties. But Europe is poised to add a tough-love tactic on the side. Will it help?

What happens when one trading power​ ​is trying to drive down carbon emissions, and other nations aren’t moving so fast? That’s a hot question for the European Union, which makes its heavily polluting industries pay for their pollution while ​many other countries don’t.

Leaders in the EU have long argued that it’s time to level the playing field. Now they have a plan to use their market power to bring others into line​.​

The ​penalties they envision might have a side benefit for Earth’s climate by nudging other countries to ratchet down their own emissions.

A key goal is to fix what is now a “leaky” system. Inside the EU, there’s a robust carbon market with rules and prices that push industries to reduce pollution. But goods imported from outside don’t typically face such constraints.