Two years ago, Congress told the Environmental Protection Agency to require major U.S. industries to measure the amount of carbon dioxide they emit each year as a step in the process of creating legislation to reduce gases that cause climate change.

But the agency fought the order, claiming that the Clean Air Act doesn’t give it the authority to police carbon dioxide and other heat-trapping gases. The agency also ignored a U.S. Supreme Court ruling, which said that — yes — it did too have the power to regulate these emissions.

The agency’s foot-dragging on controlling carbon-dioxide emissions now appears to be over.

Last week, the EPA announced that it will comply with Congress’ 2007 statute by calling on all big industries to measure carbon-dioxide emissions by the end of this year. EPA administrator Lisa P. Jackson has indicated that the agency will be taking a far different stance on global climate change.

This is good news.

Soon after Jackson was sworn in, the agency reversed course on a controversial decision.

Under the Clean Air Act, California can seek waivers to impose higher air-quality standards than the federal rules to combat smog. In almost every case, the EPA has granted the waivers.

But when California asked the EPA for a waiver to impose tougher regulations on vehicles’ carbon-dioxide emissions a few years ago, the EPA said no. Some 15 other states, including Florida, want to adopt the California carbon-dioxide emission standards. At the moment, these plans are in limbo.

After Jackson arrived, the EPA said that it would review the California waiver request. Many believe this means the agency will ultimately grant the waiver, opening the way for the other states to impose tougher emission standards, too.

Controlling the emissions that cause global warming is such a vital issue that the country must do something about it soon.

With the EPA on board, Congress must step up, too.