The millions of dollars in TV ads that liberal environmentalist Tom Steyer plans to spend in the midterms begins today – with the release of his NextGen Climate’s multi-million-dollar campaign in Iowa against GOP Senate nominee Joni Ernst.

Interestingly, the focus of the ad isn’t on the environment and climate change; it’s on being tied to GOP special interests like the Koch Brothers and Grover Norquist.

NextGen Climate says this ad is the first of a series in ads about Ernst’s ties to GOP special interests. It’s a $2.6M buy over five weeks in Des Moines, Cedar Rapids, and the Quad Cities markets.

Here’s some background on Steyer’s campaign.

Mark Murray is the Senior Political Editor at NBC News, where he covers politics for the network, writes and edits its popular “First Read” blog, and appears daily on MSNBC and Washington DC’s NBC affiliate to discuss the latest political news.