The former head of the U.S. Environmental Protection Agency delivered a rousing call-to-action Wednesday to Maine environmental and conservation leaders in the face of the Trump’s administration attempts to rollback policies on climate change and pollution.

In a speech to several hundred at a Maine Conservation Voters event in Portland, former EPA Administrator Gina McCarthy was fired-up and sometimes irreverent as she predicted that President Trump will ultimately fail in his quest to undo the major policy initiatives achieved under President Obama. McCarthy said the Obama administration “followed the law” when it developed regulations – including the Clean Power Plan that sought to impose the first federal limits on carbon dioxide emissions nationwide – that were based on years of science and unprecedented outreach.

“Believe me, I know that ‘Everything we did is now being rolled back,'” McCarthy said, eliciting laughs from the crowd as she threw up her hands and exaggerated the last phrase.

“But let me tell you something: an announcement in the Rose Garden doesn’t mean anything,” continued McCarthy, EPA administrator from 2013 to 2017. “It is a press release and a statement. What means something is final rules of the United States of America, and when you do them right, you can’t undo them with a Rose Garden announcement. You can’t absolve the United States of America from its responsibility to be part of the international community. And it is not going to actually live well beyond today.”

Environmental activists and organizations have good reason for concern these days.

The Trump administration has begun systematically undoing – or attempting to undo – most of the major environmental and climate change policy achievements under his predecessor. In addition to the Clean Power Plan, which Trump officials have pledged to repeal or weaken, the administration has moved to withdraw the United States from the Paris climate agreement, begun the process of rolling back stringent vehicle emissions standards and relaxed regulations on the oil, gas and coal industries. Staffing levels at the EPA have also fallen significantly under Trump.

Business groups have applauded many of the changes and praised Trump for following through on his campaign pledges to eliminate what he says are unnecessary, overly burdensome or costly regulations. Trump’s skepticism about the role that humans are playing in climate change has played well with his base and in conservative Republican circles but infuriates progressives and runs contrary to the scientific consensus.

Nonetheless, McCarthy told those in attendance – leaders of environmental and conservation groups, activists and elected officials – that she feels hopeful. In fact, the former EPA administrator had the crowd cheering as she all but threatened (in jest) the group not to be optimistic.

“If you think that you can just mope around and whine, saying ‘Oh, it’s all gone to hell in a handbasket’ . . . and that I’m going to let you get away with it, I’m not,” McCarthy said. “I’m going to slap you upside your head and tell you that if I can get up every morning and be hopeful, then get your (expletive) out of bed and be hopeful, too!”

McCarthy, who is currently a fellow at Harvard University’s Kennedy School, said wanting clean air and water are not partisan issues and that she believes most Americans believe climate change is real because they are already seeing impacts. And McCarthy predicted that the attempts to undo recent environmental regulations would be a wake-up call to supporters of those policies.

“The one good thing about today is that while they want to toss everything up in the air, it’s still stuck to their fingers because they don’t know how to do it,” McCarthy said. “They are not getting it right. Every time they try to roll things back or delay, the courts are whacking them right back at them. As long as this ping-pong continues, we won’t make progress at the federal level, I understand that. But it ain’t going to be rolled back. And guess what? The rest of us are going to come alive.”

Beth Ahearn, program director for Maine Conservation Alliance, which sponsored Wednesday’s “Evening for the Environment” with Maine Conservation Voters, praised McCarthy for her pointed message about the impacts of climate change.

“We are all experiencing extreme weather; half of our country is burning and the other half is under water,” Ahearn said in a statement. “McCarthy’s words reinforce how essential it is to address climate.”