A Super PAC funded by liberal billionaire and environmentalist Tom Steyer has announced it will spend as much as $100 million this election season attacking Republicans in seven key states who it says are climate-science "deniers."

"I think the climate is changing, but I don't believe humans are causing that change to the extent that's been in the news."
Colorado Rep. Cory Gardner

The Republicans being targeted by Steyer's political committee, NextGen Climate Action, include Govs. Rick Scott of Florida, Paul LePage of Maine and Tom Corbett of Pennsylvania, as well as GOP Senate candidates Cory Gardner in Colorado, Joni Ernst and Mark Jacobs in Iowa, Terri Lynn Land in Michigan and Scott Brown in New Hampshire.

These states – all of which President Barack Obama won in both 2008 and 2012 – also play an important role in 2016, given that Iowa and New Hampshire are early presidential nominating contests, and that Colorado and Florida are top general-election battlegrounds. 

"Our goal is very clear – to impact the politics as it relates to climate change," Chris Lehane, Steyer's political adviser, told a group of reporters in unveiling NextGen Climate's campaign strategy.

The effort is intended to turn out Democratic-leaning voters (such as minorities and young adults) and to paint targeted Republican candidates as anti-science. That, Lehane said, is "a tough brand to win elections around."

NextGen Climate also will highlight the campaign contributions these Republicans have received from oil interests, Lehane added.

The campaign by Steyer – a former hedge fund manager who has become a prominent opponent of the Keystone XL Pipeline – comes after Florida Sen. Marco Rubio, a potential Republican presidential candidate, expressed doubt over scientists' claims that humans are responsible for climate change. "I do not believe that human activity is causing these dramatic changes to our climate the way these scientists are portraying it," he said in an interview with "This Week" host Jonathan Karl. "I do not believe that the laws that they propose we pass will do anything about it, except it will destroy our economy."

NextGen Climate argues that the Republicans it has targeted have said something similar. "I have not been convinced," Gov. Scott said of global warming when he was campaigning in 2010.

"I think the climate is changing, but I don't believe humans are causing that change to the extent that's been in the news," Colorado Rep. Gardner said in 2010.

Former Massachusetts Sen. Scott Brown, who is running for the Senate in New Hampshire this year, has said he believes in climate change and that it's caused by a combination of man-made and natural factors. But he has been a proponent of building the Keystone XL Pipeline.