The Union of Concerned Scientists is organizing a series of house parties across the state at 7 p.m. next Thursday, Sept. 23, to rally opponents of Proposition 23, the measure on November’s ballot that would roll back California’s landmark greenhouse gas emissions law.

“The Valero and Tesoro oil companies of Texas and Koch Industries of Kansas want to stifle competition from clean energy industries and protect their profits by continuing to pollute our state with their dirty fossil fuel emissions,” the news release says. “A broad coalition is working to defeat the dirty energy proposition in order to protect California’s air quality and new jobs and companies in the burgeoning cleantech sector, and to promote energy security.”

Partygoers will watch the premiere of a mini-documentary about Prop. 23, “learn why defeating it is so important for California and the rest of the nation, and share tools for increasing voter turn-out to defeat the dirty energy proposition at the polls,” the release says.

Parties are planned all over the Bay Area, according to the UCS website; there’ll be a big one at the Chabot Space and Science Center, 10000 Skyline Blvd. in Oakland, which is free and includes refreshments but requires an RSVP.

I don’t see that the “Yes on 23” committee has any similar events scheduled. UCS is part of the coalition behind the main “No on 23” committee, but I hear there’s a new coalition about to take shape against the measure as well; watch for an announcement Monday.