EPA Administrator Gina McCarthy testifies during a House Oversight and Government Reform Committee hearing in March. On Monday, she said the nation’s switch to cleaner sources of energy will continue even under a Donald Trump presidency. (Pete Marovich/Bloomberg)

The head of the Environmental Protection Agency on Monday gave an impassioned defense of the Obama administration’s energy and environmental policies and insisted the nation’s shift from fossil fuels will continue no matter who occupies the White House.

“The inevitability of our clean energy future is bigger than any one person or one nation,” Administrator Gina McCarthy said in a speech at the National Press Club that was twice interrupted by protesters. “It must be guided by a simple but profound truth: We don’t have to choose between economy or environment. We can and we must choose both.”

McCarthy mostly deflected specific questions about worries over President-elect Donald Trump, who has been a blistering critic of the EPA. Trump has vowed to scrap what he sees as onerous regulations the agency has put in place in recent years, from tighter methane controls on domestic drillers to the administration’s signature effort to regulate greenhouse-gas emissions from power plants. He also has vowed to end the “war on coal,” expand oil and gas leasing across federal lands and waters, and “cancel” U.S. participation in an international climate agreement aimed at reducing carbon emissions.

But McCarthy, a Boston native who became the EPA head in 2013 after a lengthy confirmation fight, repeatedly suggested that trying to slow the country’s move away from coal and other fossil fuels and toward cleaner energy sources ultimately would be foolish and futile.

“Science tells us that there is no bigger threat to American progress and prosperity than the threat of global climate change,” she said. “And if you take nothing else from my speech today, take this: The train to a global, clean-energy future has already left the station. We have a choice. We can choose to get on board, to lead. Or we can choose to be left behind.”

McCarthy ticked off statistics detailing what she called the rapid progress of recent years: Vehicles are becoming more fuel efficient. Power plants have reduced mercury pollution. Many companies are on their way to meeting the requirements of the Clean Power Plan — even as its fate remains in federal court — and dozens of states are hitting lower emissions targets years ahead of schedule. U.S. leadership on climate action has compelled other nations around the world to follow suit.

“We’re in a spectacularly different place today than we were when President Obama took office,” she said. “Before, developing countries would point a finger at us. Now they’re wondering if the U.S. will turn its back on science and be left behind. That is the choice that we face.”

Since the election, there has been a palpable sense of unease among many EPA employees because Trump promised during his campaign to essentially gut the agency. Scientists and environmental activists are alarmed that the Trump EPA transition is being led by Myron Ebell, a climate-science skeptic who has argued for abandoning the international Paris climate accord and opening up more federal land to coal mining and oil exploration.

Activists have started petitions and held a public protest against Ebell’s role, and on Monday afternoon, the Sierra Club and several other groups were planning to project giant messages across the front of EPA headquarters.

Asked about the angst within the agency, McCarthy demurred.

“My folks, they’re doing fine. Most of them have been through transitions before,” she said. “They are working with one another, just continuing to hunker down and do their jobs. They are pretty confident that the mission of the EPA is a good one and that it will be enduring.”

She also said she expects that cities and states will forge ahead on climate action and pick up the slack should the federal government under a Trump administration begins to reverse course.

“There are thousands of mayors who have signed climate pledges. They are working hard” because of their fears, she said. “They are afraid of wildfires. They are afraid of floods. They’re afraid of running out of drinking water, which is particularly frightening. These things are happening all across the country. So, mayors will continue to speak up. Cities will continue to be some of our best and loyal allies.”

She was asked what guidance she would give her successor, even if that’s someone who views the agency’s role in starkly different terms. “My advice would be to listen to the great staff at EPA,” McCarthy said. “They are experts in these issues. They will give you an opportunity to lead. I would suggest you take it.”

Read more at Energy & Environment:

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Obama administration cancels oil and gas leases on Blackfeet tribe’s sacred grounds

The Gulf oil spill caused more land to fall into the ocean, scientists say

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