Fredreka Schouten

USA TODAY

WASHINGTON — Billionaire environmental activist Tom Steyer will target Republicans in seven Senate and governors' races this year, as he pushes to make climate change a top issue in November's elections, his political aides announced Wednesday.

His campaign — which will include television ads and on-the-ground efforts to persuade women, young adults and minorities to vote in traditionally low-turnout midterm elections — will hit Republicans in competitive Senate contests in Colorado, Iowa, Michigan and New Hampshire.

Those seats, all currently held by Democrats, are crucial to Democrats' efforts to retain their Senate majority in November. They also are key to the party's chances of holding the White House in 2016.

Steyer also will spend heavily to shape governor's races in Maine, Pennsylvania and Florida, another presidential swing state, where Gov. Rick Scott has said he is not convinced that climate change is caused by human activity.

"The issue of climate change has become much more real to folks on an everyday basis," said Chris Lehane, chief strategist for Steyer's political arm, NextGen Climate Action. He said the group will brand Republicans in these contests as "anti-science."

The NextGen team also will work to tie climate change to voters' health and economic concerns, such as rising flood-insurance rates in Florida and crop-killing droughts in the Midwest, officials told reporters at a briefing.

Steyer, who made more than $1.5 billion from his time running Farallon Capital Management, already has pledged to spend $50 million of his own fortune on 2014 races. He plans to raise another $50 million from other donors.

Lehane said Steyer's team still is talking with other potential donors about their financial commitments, but said Steyer may opt to spend more than $50 million. "Tom has not been shy about opening up his pocketbook," he said.

Steyer's political investment stands to make him one of the biggest outside players in this year's elections and the largest Democratic rival to the conservative political operation funded by billionaire industrialists Charles Koch and David Koch. A Koch-affiliated group, Americans for Prosperity, already has spent more than $35 million to attack vulnerable Senate Democrats for their support of the Affordable Care Act and has indicated it could spend $125 million this year.

"We are spending a drop in the big oil bucket," Lehane said.

Republicans have hit back on Steyer. Earlier this month, the Republican National Committee released a memo that portrayed him as a hypocrite, saying he had made money from a fund that invested in oil and gas — even as he advocated to reduce carbon emissions. Steyer is one of the nation's most vocal opponents to the Keystone XL pipeline that would take carbon-heavily oil from the tar sands of Alberta, Canada, to Gulf Coast refineries.

'I don't think that Americans who are struggling to buy gas for their cars ... are going to take lessons in civic virtue from a billionaire environmentalist," said Tim Phillips, president of Americans for Prosperity.

Steyer's aides said he has divested his interests in coal and tar sands since his 2012 retirement from Farallon. His remaining investments in clean-energy interests are held by charitable foundations and trusts that donate those earning to non-profit organizations, they said. "He does not personally benefit financially," spokeswoman Heather Wong said.

In picking the seven races, Steyer has opted so far against targeting vulnerable Democratic senators up for re-election who support the pipeliine, such as Louisiana Sen. Mary Landrieu.

"We want to see the Senate remain in Democratic control," Lehane said.

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