FRESNO, Calif. (AP) — An environmentalist billionaire who has pledged to spend tens of millions of dollars targeting Republicans who reject climate change announced Friday that he is now creating a fund to help victims of extreme weather disasters, starting with wildfires in the American West.

Tom Steyer and his wife, Kat Taylor, launched the Climate Disaster Relief Fund that will draw on the couple's personal profits from investments in Kinder Morgan, one of the largest energy companies in North America.

Climate change leads to warming temperatures, drought and insect outbreaks, which exacerbate costly wildfires, Steyer said in a statement.

"Climate change is the defining issue of our generation," he said. "We can no longer afford to wait to address this very real threat."

A retired hedge fund manager and longtime Democratic donor, Steyer has pledged to spend up to $100 million this year in political campaigns nationwide to shape climate policy — half his money and the rest raised from likeminded donors. The money will be used to back Democrats and attack Republicans running for Senate in New Hampshire, Iowa, Colorado and Michigan, and for governor in Pennsylvania, Florida and Maine.

Steyer's group, NextGen Climate, did not immediately respond to requests for comment, but the San Francisco Chronicle reported that the disaster fund will start with up to $2 million. The statement did not elaborate on the funding.

Steyer cited studies that predict climate change could double the threat of wildfires in the southern Rockies and increase that threat by 74 percent in California.

Firefighters and nurses on the front lines of these disasters will be among the first to receive money from Steyer's fund to be managed by the San Francisco Foundation. The fund will also provide relief to victims of oil spills, droughts, floods and other disasters related to extreme weather or climate change, Stayer said.