This post has been updated.

Billionaire environmentalist Tom Steyer announced Monday that his super PAC will spend $25 million this year to mobilize young voters in battleground states, hoping to harness climate change as a galvanizing political issue on college campuses.

The campaign represents a new focus for NextGen Climate Action, which spent $74 million in the 2014 midterms to support Democratic congressional candidates, including $19 million on ads. But its top two Senate targets — Republicans Cory Gardner of Colorado and Joni Ernst of Iowa — prevailed.

NextGen Climate has not ruled out running a media campaign again in the fall, but it is currently devoting its resources to a seven-state effort to register millennials on 203 college campuses and get them to the polls, officials said.

"This generation is super smart, incredibly passionate, and strongly prefers candidates who embrace clean energy solutions,“ Steyer said in a statement. “That’s why I’m so excited to support the next generation in making sure their voices resonate at the ballot box.”

The campaign will focus on young voters in Pennsylvania, Iowa, Ohio, New Hampshire, Nevada, Illinois and Colorado — states that could be pivotal to the Democrats' efforts to win the White House and retake control of the Senate. An early training effort for organizers will provide them with digital and data tools to help identify and mobilize college students, the group said.

Just 41 percent of 18- to 29-year-olds voted in 2012, down from a record high of 48 percent in 2008, according to the U.S. Elections project. Overall turnout in 2012 was 59 percent.

Steyer, who made his fortune as a hedge fund executive, gave $17 million to NextGen Climate through the end of February, making him the top super PAC donor of 2016 so far. He told The Washington Post earlier this year that he plans to spend more this cycle than the $70 million he put into his super PAC in 2014.

Scott Clement contributed to this report.