In the US, oil billionaires David and Charles Koch have decided to try to end California’s global warming law with a large money contribution.

The pair, who own the nation’s second-largest private company with oil refineries and pipelines, have made a $1 million contribution to the campaign against Proposition 23.

They have joined with two other oil companies from Texas, Valero Energy Corp and Tesoro Corp, in adding their support to making the proposition fail.

The proposition, lauded by environmental groups and California governor Arnold Schwartzenneger, seeks to reduce greenhouse gas emissions statewide to 1990 levels over the next decade.

The company associated with the Koch brothers said they believed the law would cause significant job losses and higher energy costs.

The Koch brothers are known for the stance on what they view as excessive government regulation.

They have helped finance efforts to develop arguments against global warming.