Environmentalists are unimpressed with George Bush's pledge to develop alternative sources of energy - accusing him of failing to confront the real issues driving climate change.
In his address on Tuesday, Mr Bush called for a large boost in the production of alternative fuels, along with an increase in efficiency standards for petrol-engine vehicles. "These technologies will help us be better stewards of the environment, and they will help us to confront the serious challenge of global climate change," he said.
Mr Bush recommended a five-fold increase in the production of ethanol and other alternative fuels. He said that increase in production - up to 35 billion gallons by 2017 - would replace about 15 per cent of annual petrol use. Taken with other reforms, including an annual4 per cent increase in vehicle efficiency standards starting in 2010, Mr Bush said his plan could reduce petrol consumption by 20 per cent over the next decade.
But activists said yesterday that however impressive Mr Bush's plans may have sounded - especially given his reputation for intransigence over issues such as the Kyoto treaty - they offered little in substance.
"There is no revolution in global warming policy in anything the President is proposing, no matter how the White House tries to spin it," said Philip Clapp, the president of the National Environmental Trust. " The numbers are calculated to sound big and impressive but the President is being just as intransigent on global warming as he is on Iraq, ignoring Congress, major business leaders, and the public, who have called for action. "
He added: "The President's proposals will contribute almost nothing to stopping global warming. They will allow our carbon emissions to grow by 14 per cent over the next 10 years."
Others welcomed Mr Bush's acknowledgement of the threat of global warming but warned that some of his proposals could do more harm than good.
"Wrongheaded approaches would prove counter-productive - we could end up with somewhat more efficient vehicles running on much dirtier fuels that further accelerate global warming," said Frances Beinecke, the president of the Natural Resources Defence Council. "Turning coal into liquid transportation fuel, for instance, would generate nearly twice the amount of global-warming pollution that today's petroleum-based fuels do.
"Similarly, producing alternative fuels such as ethanol from wood chips that come from endangered forests could inflict widespread ecological damage. "
Environmentalists remain sceptical of the benefits of ethanol production, which would provide a boost to US corn growers but which may do little to ease carbon emissions. While burning ethanol produced by corn is " carbon neutral" - it releases the carbon it has stored during its growth - production of ethanol requires fossil fuels. "Transportation of the fuels, processing of the fuels - all that requires energy which is currently driven by a fossil-fuel economy. So all these biofuels projects currently add to the greenhouse-gas effect," said Jan Kowalzig of Friends of the Earth Europe.
Campaigners said it was of equal importance that Mr Bush failed to talk about a cap on carbon emissions - something his administration has always opposed, despite calls for such a limit both inside and outside the US. "He remains delusional," Greenpeace's Steve Sawyer told the Agence France Presse news agency.
Others welcomed Mr Bush's comments. Sir Nicholas Stern, the chief economic adviser to the British Government and the author of a report that warned of the rising costs of climate change, said at the World Economic Forum in Davos, Switzerland: "There is a recognition of the link between climate change and human activity. You have to recognise what everyone is doing."
The idea behind biofuel is that you are exploiting a sustainable source of energy in the form of the carbohydrates stored within a cereal crop - in this case, maize.
Plants are able to convert the energy of sunlight into carbohydrates by the process of photosynthesis, which also led to fossil fuel production hundreds of millions of years ago.
The carbohydrates of biofuel crops are fermented into ethanol, that can be burnt in car engines converted for the task. It produces less pollution than petrol but still emits greenhouse gases.
In theory, the process should not add to the overall level of atmospheric CO2 - subsequent biofuel crops would absorb most of the emissions when they are growing. But industrialised countries rely on fossil fuel to farm arable crops.
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