The Supreme Court’s decision in Sackett v. EPA last year sharply limited the scope of wetlands protected under the Clean Water Act. Now, only wetlands with a “continuous surface connection” to navigable waters qualify as “waters of the United States.” This decision excluded millions of acres of wetlands that had long been safeguarded, leaving them vulnerable to development and destruction. In addition, North Carolina and Indiana have since moved to restrict their own wetlands protections to match the Court’s narrowed definition, even though the ruling did not require them to do so.

The loss of protection is significant. Not only does it affect water quality and flood protection, but wetlands are one of our planet’s most powerful carbon sinks. Waterlogged soils trap organic material that would otherwise decompose and release CO2, locking away carbon for centuries. When wetlands are drained or filled, this stored carbon is released back into the atmosphere, turning ecosystems that once helped regulate climate change into sources of emissions.

By narrowing the definition of protected wetlands, Sackett risks accelerating both biodiversity loss and climate instability. Moving forward, we need to keep a close eye on how the states will choose to respond and how conservation strategies can be adapted to protecting wetland environments in those states that have already narrowed protections.