New Mexico climate groups struck a defiant tone in the wake of the U.S. Environmental Protection Agency’s plan to dismantle federal authority to reduce one of the drivers of climate change: greenhouse gases.

EPA chief Lee Zeldin proposes a repeal of the Endangerment Finding on climate change. State Sen. Ed Markey is fighting back.

What is the agency actually proposing? In 2009, the EPA reached what is known as the “endangerment finding” — a determination that greenhouse gases are dangerous to human health because of their role in climate change, on which the agency’s efforts to regulate greenhouse gas emissions rests. Now, the EPA proposes rolling back that finding.