Two Texas-based refinery giants have pledged as much as $2 million to fund signature gathering for a ballot initiative to suspend California’s landmark global warming law, according to Sacramento sources.

The companies, Valero Energy Corp. and Tesoro Corp., own refineries in California that would be forced under the law to slash emissions of heat-trapping greenhouse gases.

Campaign workers began collecting signatures Tuesday for the initiative, which would delay regulations to implement the nation’s most comprehensive climate legislation until California’s unemployment level drops to 5.5% for at least a year.

The current jobless rate is more than 12%.

Gov. Arnold Schwarzenegger, a strong supporter of AB 32, the global warming law, had asked businesses not to support the ballot measure, which was launched by a coalition of Republican politicians and conservative activists.

California companies, according to a source close to the administration, “are more tolerant of California’s environmental leadership. But these Texans don’t want to pay to cut their emissions in California if the federal government is not going to pass climate legislation. They can throw a few mill- ion dollars into” fighting the law.

A federal climate bill, passed by the U.S. House last June, has stalled in the Senate in the wake of intense lobbying by coal and oil companies, which would be forced to cap their emissions. Scientists say carbon dioxide and other gases are trapping heat in the atmosphere and disrupting the planet’s climate.

Meanwhile, the recession and high unemployment rate have pushed environmental issues far down the list of public concerns, at the same time that conservative groups have latched onto global warming as a way to attack the Obama administration.

A Tesoro spokesman did not respond to inquiries. But the company’s website invites visitors to lobby Congress to ensure “fair” climate legislation and fight any effort by the Environmental Protection Agency to regulate greenhouse gases under the Clean Air Act.

Bill Day, a Valero spokesman, declined to confirm or deny the company’s involvement, saying that “any contributions would come out in normal disclosures” under California’s campaign laws. He referred a reporter to Goddard Claussen, a Sacramento political consulting firm, which is handling the ballot campaign.

However, Day added in an e-mail that Valero had set up a website, www.voicesforenergy.org, “to educate consumers about the federal cap-and-trade legislation. Valero has been very outspoken about the dangers of these proposals and the fact that they would badly damage the economy while having no effect on climate change.”

The initiative sponsors, including Assemblyman Dan Logue (R-Marysville), Rep. Tom McClintock (R-Granite Bay) and the People’s Advocate, a Sacramento-based anti-tax group, have until April 24 to gather 433,971 valid signatures to qualify it for the November ballot.

margot.roosevelt@latimes.com