The hosts of ABC's The View praised former vice president Joe Biden for promising to cure cancer if he’s elected in 2020, but they expressed worry that global warming could stop him.

Co-host Meghan McCain, whose father Sen. John McCain (R., Ariz.) passed away from brain cancer last year, said cancer research should be central to candidates' platforms. After the audience applauded, co-host Joy Behar said they shouldn't be too enthusiastic about the prospect of ending cancer because global warming makes it "much more difficult."

"To that statement I would say that curing cancer is going to be much more difficult when there's so much climate change and pollutants in the environment because a lot of cancer is environmentally caused and this president rolls back anything that will clean the air," Behar said, without citing any particular policies. "They're working against each other if they don't also clean up the emissions."

McCain hopped back in to clarify that there's no evidence global warming causes brain cancer.

"They don't know what causes brain cancer, for whatever it's worth," McCain said. Behar conceded that was true.

Concurring with the group's belief that cancer should be stopped, co-host Whoopi Goldberg said the problem with such initiatives is that people don't believe they're possible. She said Biden should not give up on the dream, comparing his ambition to that of Polish scientist Marie Curie, the only person to win the Nobel Prize in two different scientific fields (physics and chemistry).

"I think of Madame Curie, I think of all the great scientists who said, ‘You know what? I know this sounds crazy, but I'm going for it anyway.' So you know what, Joe? If you can get us to the point where we eradicate cancer, that would be fantastic. I would love that," Goldberg said before changing the subject to Pride month.