Brian Rudman: White roofs are good for society

In 50 or 80 years, when Auckland's low-lying sewage treatment plant is engulfed by inexorably rising tides, our grandchildren, hastily digging backyard long-drops, will not be praising this generation's equivocation over global warming.

John Key and his Cabinet colleagues obviously accept the scientific argument that global warming, caused by human activity, is threatening the planet's existence. Otherwise why, on Monday, did they set a target of 10-20 per cent reduction in carbon dioxide emissions by 2020?

But having accepted the science, they then decided their political careers were more worthy of saving than life on earth as we know it. Instead of following the scientific case to its logical conclusion, they've chickened out, calling for a special dispensation for little old New Zealand.

We're an insignificant dot at the bottom of the map overrun by millions of sheep and cattle who won't stop farting. Pretty please. Give us some slack. It's their fault, not ours.

Of course the Key Government is not alone. A recent article in New Scientist noted how it's 44 years since United States President Lyndon Johnson's scientific advisers warned that greenhouse gas emissions could generate "marked changes in climate". Author George Marshall noted that since then, $4.4 billion a year had been spent on research, conferences and learned articles on the issue, but still, 40 per cent of Britons and 50 per cent of Americans resolutely refuse to accept that emissions are changing the climate.

Marshall blames the scientists for failing to sell their compelling story to the public, noting how the prestigious, United Nations-backed Intergovernmental Panel on Climate Change "has no human face at all". He has a point. But it's not just the scientists. The politicians pushing the cause are doing an appalling PR job as well.

Fancy pinning the future of the planet on a process labelled "emissions trading". What a marketing nightmare. Getting buy-in for something with emissions in its title is bad enough. But after the past two decades, anything associated with global trading of paper credits has an uphill struggle too, triggering images of fat cat brokers in Zurich or London laughing all the way to their private bank vaults.

Of course, reducing greenhouse gas emissions by up to 40 per cent, and quickly, is what the scientists argue is required to give the earth's climate a chance to stabilise.

But there are also proposals being advocated, for ways of buying more time. The simplest, and one most likely to get buy-in from the public and politicians alike, is to paint your house - and in particular the roof - a reflective white or grey.

US President Barack Obama's Nobel prize-winning Secretary of Energy, Dr Steven Chu, is a fan, saying that this roof painting, and making pavements and roads white or light-coloured, would be the equivalent of taking all the cars in the world off the road for 11 years.

Done worldwide, this whitening of the environment would offset about 44 billion tonnes of carbon dioxide. That's roughly the equivalent of 18 months' emission of carbon dioxide into the atmosphere worldwide.

The State of California has already latched on, following a campaign by prominent scientist Hashem Akbari, and in 2005 passed a building standard requiring the builders and retro-fitters of flat-top buildings to first consider cool colours for the roofs.

Akbari, a senior scientist at the Lawrence Berkeley National Laboratory, was triggered by memories of the white houses of his boyhood in Tehran. He calculates that in a densely packed urban heat island like the Los Angeles Basin, temperatures would drop as much as 5C if all black surfaces were converted to white. Every 10sq m of black rooftop converted to white could offset around a tonne of carbon dioxide.

Earlier this year he told the San Francisco Chronicle, painting your roof white "will be good for you, it will be good for your neighbours, and it will be good for society".

This is what the Government should be encouraging to get buy-in from a sceptical public. Give away the paint, perhaps, in exchange for the carbon credits.

On a much grander scale is the proposal for a fleet of cloud-making ships, which the London Times recently claimed the Royal Society was about to endorse. Rival teams of British and US scientists are working on schemes involving a fleet of 1900 wind-powered ships, unmanned and satellite-controlled, out in the mid-Pacific, pumping a fine spray of seawater up into the sky to reflect sunlight back into the atmosphere.

With someone called Professor Stephen Salter being one of the ideas men for pumping salt water into the sky it deserves to succeed. Based on a design dating back to 1926, the ships would drag propeller-like turbines behind them to generate the electricity needed to pump the spray into the air.

The clouds would reflect 1 to 2 per cent of the sun's heat, which would be enough to cancel out the greenhouse warming caused by carbon dioxide emissions. It's been estimated it would cost $22 billion over 25 years to trial and launch the fleet. Given that the United States plans to spend around $250 billion on the wars to save democracy in Afghanistan and Iraq this year, and the Stockholm International Peace Research Institute says total world military expenditure in 2007 was $1.981 trillion, a mere $22 billion to try to save the planet hardly seems excessive.