President Barack Obama's climate change policy is in crisis amid a barrage of US lawsuits challenging goverment directives and the defection of major corporate backers for his ambitious green programmes.
The legal challenges and splits in the US climate consensus follow revelations of major flaws in the UN Intergovernmental Panel on Climate Change (IPCC) report, which declared that global warming was no longer scientifically contestable.
Critics of America's Environmental Protection Agency (EPA) are now mounting a series of legal challenges to its so-called "endangerment finding" that greenhouse gases are a threat to human health.
That ruling, based in part on the IPCC's work, gave the agency sweeping powers to force business to curb emissions under the Clean Air Act. An initial showdown is expected over rules on vehicle emissions.
Oil-rich Texas, the Lone Star home state of Mr Obama's predecessor George W Bush, is mounting one of the most prominent challenges to the EPA, claiming new regulations will impose a crippling financial toll on agriculture and energy producers.
"With billions of dollars at stake, EPA outsourced the scientific basis for its greenhouse gas regulation to a scandal-plagued international organization that cannot be considered objective or trustworthy," said Greg Abbott, Texas's attorney general.
"Prominent climate scientists associated with the IPCC were engaged in an ongoing, orchestrated effort to violate freedom of information laws, exclude scientific research, and manipulate temperature data.
"In light of the parade of controversies and improper conduct that has been uncovered, we know that the IPCC cannot be relied upon for objective, unbiased science - so EPA should not rely upon it to reach a decision that will hurt small businesses, farmers, ranchers, and the larger Texas economy."
Mr Abbott’s comments follow the controversy over the work of the University of East Anglia’s Climate Research Unit, whose research was at the heart of IPCC findings. Leaked emails indicated that the freedom of information act was breached and that data was manipulated and suppressed to strengthen the case for man-made climate change.
A series of exaggerated claims, factual mistakes and unscientific sourcing have subsequently been uncovered in the 2007 IPCC report - such as the alarming but unjustified warning that Himalayan glaciers might disappear by 2035. Scientists insistent that humans are causing climate change have said the mistakes do not overturn an overwhelming burden of proof backing their case.
The case brought by Texas is one of 16 challenging the IPA over its data or procedures. They have been lodged variously by states, Republican congressmen, trade associations and advocacy groups before last week's cut-off to file court actions.
The pro-market Competitive Enterprise Institute (CEI) and US Chamber of Commerce are also mounting high-profile battles to overturn the EPA decisions through petitions filed with the US Circuit Court of Appeals in Washington.
"The Clean Air Act is an incredibly flawed way to regulate greenhouse gas emissions and the findings on which it is based are full of very shoddy science," said Myron Ebell, director of energy and global warming policy at the CEI.
"Many policies and proposals that would raise energy prices through the roof for American consumers and destroy millions of jobs in energy-intensive industries still pose a huge threat."
Among those he listed were the EPA's decision to regulate greenhouse gas emissions using the Clean Air Act, efforts to use the Endangered Species Act to stop energy production and new power plants, the higher fuel economy standards for new passenger vehicles enacted in 2007, and bills in Congress that require buildings to use more renewable electricity and introduce higher energy efficiency standards.
The EPA, a federal agency which is increasingly key to Mr Obama's green agenda as his legislative policies become bogged down in Congress, refuted the charges.
"The evidence of and threats posed by a changing climate are right before our eyes," said Catherine Milbourn, EPA spokeswoman. "That science came from an array of highly respected, peer-reviewed sources from both within the United States and across the globe."
The Environmental Defence Fund is leading the defence of the EPA's findings, arguing that critics are deliberately ignoring science to set back efforts to tackle climate change. "The EPA's decision is based on a 200-page synthesis of major scientific assessments," said the Fund, denying the work was simply attributable to the IPCC.
Also last week, the United States Climate Action Partnership, a grouping of businesses backing national legislation on reductions of greenhouse gas emissions, suffered a major blow when oil firms BP America and Conoco Phillips and construction giant Caterpillar left the group.
The two oil firms, the most significant departures, walked out on the industry-green alliance protesting that "cap and trade" legislation would have awarded them far fewer free emission allowances than their rivals in the coal and electricity industries.
Last week also saw the United Nation's top climate official, Yvo de Boer, announce his resignation after the failure of the recent Copenhagen climate conference to agree to more than vague promises to limit carbon dioxide emissions.