Senate Majority Leader Harry Reid (D-Nev.) continued his crusade against Charles and David Koch on Wednesday, claiming that the billionaire brothers are one of the "main causes" of global warming.

During a speech on the Senate floor, Reid cited the new White House report detailing how climate change is already underway, describing the findings as "disastrous."

"While the Koch brothers admit to not being experts on the matter, these billionaire oil tycoons are certainly experts at contributing to climate change," Reid said. "That's what they do very well. They are one of the main causes of this. Not a cause, one of the main causes."

Reid referenced a 2013 study by the University of Massachusetts Amherst that found Koch Industries to be one of the country's top air polluters.

"Charles and David Koch are waging a war against anything that protects the environment. Now I know that sounds absurd, but it's true," he said. "These two billionaire oil barons are actively campaigning now, spending tons of money against anything that seeks to curb pollution, limit our dependence on fossil fuels or lower our energy costs for working families."

The Koch Brothers, whose Americans for Prosperity super PAC is set to spend millions on the midterm elections, have become a favorite topic of Reid's in recent months. In March, the Majority Leader accused Republicans of being "addicted to Koch."

Last month, Charles Koch responded to Reid's barrage of criticism in a Wall Street Journal op-ed, accusing Reid and other Democrats of "character assassination."