Sen. John McCain (R-Ariz.) on Sunday said it's important to understand the climate may be changing.

"There is things happening with the climate in the world that is unprecedented," McCain said on CNN's "State of the Union" when asked a question regarding why Republicans act as if climate change is not real.

McCain stressed the importance of nuclear power.

"It's the cleanest, cheapest, in many ways, source of power," he said.

"We have to understand that the climate may be changing and we can take commonsense measures which will not harm the American people."

McCain's comments come as Hurricane Irma on Sunday begins to hit Florida. The Category 4 hurricane is bringing 130 mph winds and is expected to move up Florida's west coast.

It has left hundreds of thousands of people without power in the state, and millions have been ordered to evacuate.