Climate change campaigners should not have fixated on carbon dioxide

If climate negotiations 20 years ago concentrated on low-hanging fruits, the fight against global warming would have been more successful, argues Geoffrey Lean.

By Geoffrey LeanPublished: 7:45PM BST 18 Sep 2009
Here's a heretical thought, one that might even further inflame the great global-warming slanging match. Has the world set out to tackle climate change in the wrong way? It's not, I admit, the most tactful moment to put the question. On Tuesday the heads of the world's governments meet in New York for the first universal climate summit. This is just the most important of a series of high-level get-togethers addressing the issue, which started on Thursday with a meeting of ministers from the most polluting countries, and continues to the G20 summit in Pittsburgh at the end of the week. But it has to be asked. For more than 20 years the world has been trying to negotiate agreements to reduce emissions of carbon dioxide from burning fossil fuels and felling forests. But they have gone on growing: indeed, their rate of growth has been accelerating.
Concentrating on carbon dioxide was understandable. It is, after all, the biggest single cause of climate change. Scientists have known for more than 180 years that it warms up the atmosphere, and – for more than 110 – roughly what the effects of increasing its concentration would be.

But CO2 is only responsible for about half of the problem. The rest is caused by other pollutants. No worldwide attempt has been made to control some of them, even though doing so would be much less contentious and would reduce global warming far faster.
Take black carbon, which gives soot its colour. It is now accepted to be the second biggest contributor to climate change, responsible for between 10 and 25 per cent of it. Formed through incomplete combustion of wood, vegetation and fossil fuels, it lands a unique double whammy.
While in the air, it absorbs and releases solar radiation, helping to heat up the atmosphere. When it falls out on ice and snow, on mountains or at the poles, it darkens them, causing them to reflect less sunlight and melt more rapidly. And as they disappear they expose more dark land or water, which absorbs even more heat and so further warms the world.
A study by the United Nations Environment Programme concludes that the pollutant has played a major part in shrinking Himalayan glaciers, and helped disrupt the South Asian monsoon.
Then there's tropospheric ozone – the gas when it is relatively near the ground rather than in the protective layer in the stratosphere miles above our heads. Largely formed as a result of emissions from car exhausts, it is thought to contribute between six and 15 per cent of the problem.
There's compelling reason to tackle both, quite apart from climate change. Black carbon is one of the world's greatest killers, largely responsible – in smoke from inefficient woodburning stoves – for at least 1.6 million deaths annually, mainly of children, in the Third World. And, together with ozone, it helps cause 800,000 more each year worldwide from urban air pollution.
Introducing better stoves, or solar cookers, dramatically cuts emissions of black carbon, as does cleaning up emissions from diesel vehicles. And boosting vehicle fuel efficiency – and reducing pollution from other sources, ranging from oil refineries to dry cleaners – will cause less ozone to form.
Taking such steps could have an immediate effect on climate change, as both pollutants disappear almost immediately from the atmosphere – as opposed to carbon dioxide, which lasts for centuries. And they should be comparatively uncontentious. Even Senator James Inhofe, the most outspoken global warming sceptic in the American Congress, has supported a Bill on black carbon, beating Al Gore to it by a few days.
Similarly, George W. Bush helped lead a successful bid to speed up the phasing out of hydrochlorofluorocarbons – up to 1,700 times more potent than carbon dioxide in heating up the planet – under the Montreal Protocol for protecting the ozone layer. Just this week, the American, Canadian and Mexican governments have called for this treaty to be extended to tackle yet another group of greenhouse gases.
This provokes my initial question. If the climate negotiations had set out 20 years ago first to pick these low-hanging fruits, surely we would have got very much further in bringing global warming under control, while building trust to tackle carbon dioxide.
Such a strategy is no longer an option. So much time has been lost and climate change has now progressed so far that big cuts in carbon dioxide are already overdue. But attacking black carbon and the other pollutants would have an immediate impact, and could buy us some desperately needed time.
As Durwood Zaelke, the president of the Institute for Governance and Sustainable Development, puts it: "It's essential to cut carbon dioxide, but we can't win if we only target half the problem."