From what I found, this claim is true. Looking at the website Climate Action Campaign, we can see the various ways the Trump administration has worsened the climate crisis by cutting funding for existing initiatives to prevent it. As for having the "worst," this depends on what the Trump administration is being compared to. Given that climate change is getting worse, the Trump administration is setting barriers to creating renewable energy and cutting funding for preexisting solutions, setting the US and world back. This source has some bias, but climate change is widely accepted by scientists as a serious problem.
Climate Action Campaign Trump's Climate and Clean Energy Rollback Tracker - Climate Action Campaign
