Delegates to a key UN-backed climate meeting this week will be forced to consider what their future work might look like without US government participation.

The Trump administration’s actions in recent days have cast unprecedented uncertainty upon the climate panel’s work.

The Trump administration has halted the participation of U.S. scientists in key U.N. climate change assessments, two sources familiar with the situation told Reuters, part of its broader withdrawal from climate change mitigation efforts and multilateral cooperation.