Britain’s May now targeting pollution

LONDON — Britain would bring its net production of greenhouse gases to zero by 2050 under legislation Prime Minister Theresa May proposed Wednesday.

The move would make it the first of the world’s major economic powers to commit to ending its contribution to global warming.

The plan doesn’t say how the nation would reach the emissions goal or what it would cost, and future governments could change course.

In fact, the proposal appears to leave the door open to backing away from the commitment if other countries don’t follow Britain’s lead.

But May’s bill, a bid to leave a legacy in her final weeks in office, sets a new bar for measuring environmental progress by the world’s major industrial powers.

“It is imperative that other major economies follow suit,” the prime minister’s office said in a statement. “For that reason, the U.K. will conduct a further assessment within five years to confirm that other countries are taking similarly ambitious action, multiplying the effect of the U.K.’s lead and ensuring that our industries do not face unfair competition.”

Some climate activists praised May’s plan, while others said the timetable was not quick enough and the commitment not firm enough.

The finance chief in her government, Philip Hammond, has privately warned the prime minister that her proposal could cost Britain 1 trillion pounds, news reports indicate, and climate change skeptics have said even that estimate could be low. But the prime minister’s office said dire predictions like that were wrong.

A law enacted in 2008 committed Britain to an 80 percent reduction in net production of greenhouse gas emissions, and it has sharply reduced emissions since then.

The government’s advisory Committee on Climate Change reported last month that total elimination was feasible. That provided the impetus for May’s bill, which she wants Parliament to approve quickly.

The committee produced a long list of steps to reach the goal, including more energy-efficient buildings, electric vehicles, clean power production, tree planting, and capture and storage of atmospheric carbon.

May has announced her resignation as prime minister and leader of the Conservative Party, to take effect as soon as the party chooses a new leader, which is expected next month.