President Donald Trump's decision to withdraw from the Paris climate deal has "ignited" widespread environmental activism, Bob Geldof said Wednesday.

The Live Aid benefit concerts organizer labeled Trump "a vulgar fool" and said Trump's stance on climate change has encouraged several U.S. states to do more to address the issue.

Geldof, who is known for his political activism, has previously called Trump a "racist" and a "liar."

In an interview Wednesday, the 65-year-old Irish singer-songwriter told CNBC: "What's interesting is that, parallel with the withdrawal from the Paris agreement is that the states and the cities have suddenly ramped up their acknowledgement of the problem, and started implementing far greater regulations than were actually asked for by the Paris agreement."