The rule finalized by the Environmental Protection Agency rescinds a 2009 government declaration known as the endangerment finding that determined that carbon dioxide and other greenhouse gases endanger public health and welfare.
The endangerment finding by the Obama administration is the legal underpinning of nearly all climate regulations under the Clean Air Act for motor vehicles, power plants and other pollution sources that are heating the planet.
Legal challenges are certain for an action that repeals all greenhouse gas emissions standards for cars and trucks, and could unleash a broader undoing of climate regulations on stationary sources such as power plants and oil and gas facilities, experts say. Overturning the finding will "raise more havoc" than other actions by the Trump administration to roll back environmental rules, said Ann Carlson, an environmental law professor at the UCLA School of Law.