KEY POINTS:
"Something remarkable is beginning to stir, something revolutionary, historic and transformative," Arnold Schwarzenegger told UN heads of state.
"California is mobilising technologically, financially and politically to fight global climate change."
By 2006, the specialist consultancy Next 10 says, California was already employing 22,000 people in clean technology and
had claimed more patents than any other state in the field.
And the sector is growing fast.
Last year, by some estimates, venture capital into "clean technology" in California doubled to nearly US$1.8 billion ($2.26 billion).
Many, including Schwarzenegger, believe clean tech will prove the next big driver of California's economy.
"The brightest scientists ... and smartest venture capitalists are racing to find new energy technologies and the solution to global warming," Schwarzenegger said.
"Do not believe doom and gloom and disaster are the only outcomes. Humanity is smart and nature amazingly regenerative. I believe we can renew the climate of this planet."
William Reilly, affiliated to venture capitalists Texas Pacific Group, thinks California's Governor sees climate change as an opportunity for investment, for innovation.
"He speaks of broad new horizons in solar, low-carbon fuels, and energy-saving, not of lowering thermostats, putting on sweaters or turning off lights, which would play into the negative stereotype of conservation."
Examples of this "can do" outlook are easy to find. Texas Pacific Group led the US$45 billion buyout of energy firm TXU - then axed eight planned coal-fired power stations, promising efficiency savings and wind farms.
Google.org, also in California, made clean tech account for two parts of its five-point plan for tackling global problems.
Last month, German engineering firm Siemens chose California for the launch of its rebranded Mobility division, offering to solve environmental and economic problems simultaneously.
"We see a growing need for what we call complete mobility solutions," said division CEO, Hans-Jorg Grundmann.
The optimism could be the key to success as the world aims to cut greenhouse gas emissions by 60-80 per cent.
"If you can make this into a politics of opportunity, you're winning; if it's a politics of cost and burden sharing, you're not," said John Ashton, the UK Foreign Secretary's climate change spokesman.
What business and politics want to know is whether clean technology is the solution, and, if so, how nations can emulate California.
HSBC reports that globally more than US$100 billion was invested in clean energy last year, and firms in the field showed average returns on investments of more than 26 per cent in the first three quarters.
The Stern report from the UK Government in 2006 suggested global calls for low-carbon products and services would reach US$500 billion a year by the middle of this century.
Drawing the investment is a consensus on the science of global warming, with governmental pressure and consumer and business demands, finds a Lehman Brothers report.
Little sense of opportunity is apparent in much of the European debate on climate change, dominated by targets, limits, and rows on emissions.
A looming recession, budget deficit in California, falling R&D funding in the US, and warnings of a tech bubble, do not help.
Others say tech solutions distract green policy makers from cutting emissions or rely on polluting manufacture.
Yet consultant McKinsey estimates that clean technologies could deliver up to half the emission cuts required. Innovation and future technologies could deliver the other half, thinks Mindy Lubber, director of Investor Network on Climate Risk.
According to Tom Burke, founding director of E3G, clean tech must take the lead.
"If you think 6.5 billion people are going to arrive at a stable planet by voting for voluntary simplicity, you're in the religion business, not the environment business."
* PIONEERING SPIRIT TAKES THE LEAD
California's lead in clean tech is down to several factors: Arnold Schwarzenegger's leadership, tough carbon laws, solar tech investment, a vast reservoir of venture capital, entrepreneurial vigour, and a supportive, rich population.
This was shaped by history: the pioneers, a political system which empowers governors to go it alone, and the success of draconian energy efficiencies in response to the 1970s oil crises.
Oliver Hauck, head of Siemens' US transport division, believes you cannot discount California's natural beauty, which sustains public support. For the UK, the most frequent call for change looks at long-term carbon limits that force firms to invest or pay for emissions, plus standards for buildings and vehicles, and support for R&D. These policies need bold political leadership.
Tom Burke of E3G says: "If you have a clear political leader, sooner or later you'll come across one who's green too."
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