Should we scorch the sky to save ourselves?

I couldn’t resist the reference to The Matrix! In the film, we learn that the humans of the early 21st century “scorched the sky” to block out the sun’s light. The aim was to defeat their rebellious robot creations, who depended on solar energy to power themselves. It doesn’t work out well for the humans in the movie – but perhaps we should be considering using the same weapon against ourselves.

In the version of the early21st century that we live in, we also face a deadly enemy: climate change. It may be that, like the robots, this is an enemy we created ourselves – all credible scientific opinion says so. Some people still claim that humanity’s actions are not to blame – that there are other causes. It doesn’t matter. Even these people cannot deny that the world’s temperature is rising.

Working with the scientific consensus, we need to dramatically cut our carbon emissions. It seems that this is going to be harder than we hoped. The news from the Bali Conference on climate change was widely regarded as disappointing; even if we could suddenly cut our emissions, the effects of what we have already done would continue for decades.

So what can we do? I keep thinking of an op-ed article from the International Herald Tribune that appeared a few weeks ago: How to cool the sky, by respected environmental scientist Ken Caldeira. Caldeira suggests seeding the upper atmosphere with sulphates, which would reduce the amount of solar energy absorbed by the atmosphere. This would effectively create a man-made volcanic winter – or, if you like, a less apocalyptic nuclear winter. The result would be a global cooling for a period of decades – which would give us a breathing space in which to change our lifestyles and energy usage.

It’s certainly not a mainstream opinion and, as far as I can see, that column didn’t generate any significant discussion. The more I think about it, though, the more sensible it seems. According to Caldeira, the technology is relatively available. We’ve been through volcanic winters before, and the science of it seems pretty well understood – so there would seem to be little risk of catastrophically getting it wrong.

How likely is it to happen? I can’t see the US or Europe getting behind it – too many interest groups would be affected, and at the very best it would be tied down for too long by debate and wrangling.

On the other hand… I could imagine the rising Asian powers, especially the Himalayan ones, looking at this seriously. As I wrote recently, as things stand regional drought currently seems inevitable, given that Himalayan glaciers are vanishing. This affects China, India, Pakistan, Vietnam, Cambodia, Burma, and every other country whose main water sources originate in the Himalayas. Water shortages are already leading to disputes over water rights, and I can’t see how conflict can be avoided once water shortages really start to bite.

Is it unlikely that China and India, both Asian powers with space technology programs, might decide to follow this course of action? Perhaps it’s not impossible. It would without doubt be in their best interests… Of course, if they were to do it unilaterally, there would be a global outcry – but would the western, developed, countries, whose actions have caused global warming, have any moral case for complaint if developing nations took such a step to counteract it?

And, following the debate on global warming, and the technological developments being proposed as a result, I don’t find any other solution to be quite as convincing.

Update 23 December 2007:

I’ve just noted this Guardian article, which points out that if current development trends continue, the Himalayan glaciers will be gone in 40 years. An argument for drastic action…