California Gov. Jerry Brown (D) said Sunday he believes the science surrounding the deadly wildfires that have ravaged California in recent years will become so evident that climate skeptics will become believers in the less than five years.

“The last five years, the fires have never been this bad. This fire in Malibu is the worst they’ve ever seen. This fire in Paradise and Northern California was the worst in the history of California,” Brown said on “Face the Nation” on CBS.

“So yeah, you can mull the science, but I’ll tell you every year it’s going to get clearer and clearer so that I think in less than five years, even the worst skeptics are going to be believers,” he continued.

Brown said he raised evidence that climate change has worsened wildfires in California over the last 15 years during his visit with President TrumpDonald John TrumpGary Cohn says Trump trade adviser the only economist in world who believes in tariffs House transportation committee chairman threatens to subpoena Boeing, FAA communication Pentagon sets new limits on transgender service members MORE on Saturday. However, he said he didn’t harp on the issue because he was interested in cooperating with the federal government. 

“We need the money, we need federal help and we need a collaborative and cooperative spirit and we’re getting that,” Brown said. “But I did say that we’re going to look at all the elements that are causing these fires over time and we’re going to work in a way to let science be our guide and the president in no way negated that.”

“So I decided to go for an opening and I think over the next months and years you’ll see the science becoming crystal clear and even the folks in Washington that are now more in the denialist camp are going to come around,” Brown added.

More than 70 people have died from the Camp Fire raging in Northern California, making it the deadliest in the state’s history, The Los Angeles Times reported. That fire and a separate blaze in Southern California have destroyed thousands of buildings and hundreds of thousands of acres of land.

Trump visited California on Saturday to tour damaged areas and meet with those affected by the fires. It marked the president’s second time visiting California since taking office.

The president drew backlash earlier this month when he blamed poor forest management for making the fire worse, and threatened to cut off federal funding to the state. He has since struck a more collaborative note, signing an emergency declaration and appearing with Brown and California Gov.-elect Gavin Newsom (D).

Trump acknowledged in a “Fox News Sunday” interview that aired on Sunday that climate change may contribute “a little bit” to the fires, but insisted that forest management plays a larger role.