SACRAMENTO -- The Big Six automakers today put the ball back into California Attorney General Jerry Brown's court over a contentious auto emissions lawsuit.

The car manufacturers' attorney today asked Judge Martin Jenkins to dismiss a federal lawsuit against them brought by Brown's predecessor, Bill Lockyer. The case is being heard in U.S. District Court in Sacramento.

The suit requested unstated damages, estimated at many millions of dollars, from the Big Six (General Motors, Ford, Chrysler, Toyota, Honda and Nissan) for their vehicles' greenhouse gas (GHG) emissions.

Lockyer's suit alleged that the global warming these GHGs - mostly carbon dioxide - cause represents a "public nuisance" to California. This could include damage caused by phenomena like fires and flooding that some experts predict could rise in California in the future.

But attorney Ted Boutrous told Jenkins that car makers can't be held solely responsible for a widespread problem like global warming. He also stressed that the issue requires an international political solution.

Lockyer's action has been called "the state's most frivolous lawsuit" by Sacramento-based Pacific Legal Foundation (PLF), quoted in a recent LegalNewsLine, because of uncertainty over how to define "public nuisance." If successful, warned the PLF, the suit would cripple the state's economy.

Brown had long hinted that he was prepared to ditch the lawsuit and early last month made statements implying he was prepared to talk to auto manufacturing executives. Observers believed then that Brown was preparing the ground for a settlement offer, but none has emerged yet.

Jenkins indicated in today's hearing that he is uncertain about several aspects of the attorney general's case. These include at what point carbon dioxide emissions begin to cause damage and how to measure car makers' responsibility to reverse the rise.

The judge was also concerned about the suit's potential impact on the U.S. government's ability to negotiate international global-warming treaties.