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Operation Sunblock
After all our dilly-dallying about reducing our carbon emissions, it looks as though it may be time to hit the technological panic button. But Leonie Joubert wonders if new ideas about how to turn down the global thermostat might be the Frankenstein monster that finally does us in.

There’s a buzz in the corridors of science – science, mind you, not science fiction. Maybe, they’re saying, just maybe it’s time to throw a titanic sunscreen up into the atmosphere, to guard against continued rises in temperature. They’re talking about putting a field of mirrors up into orbit above Earth to reflect some of the sun’s rays away from us. Or pumping the atmosphere with the fine airborne crystals of sulphate which will block inbound heat, simulating what volcanoes do naturally. Or spraying mists of seawater up over the oceans to force cloud formation and shield us from some of that solar energy.

Here’s another one: dump tons of iron filings into the ocean – this will force plankton to grow, which will strip some of the carbon dioxide out of the atmosphere.

As bizarre as they sound, these ideas are popping up in the pages of the most reputable scientific journals in the English speaking world. And even Barack Obama’s chief science adviser John Holdren is bringing the matter up in White House meetings. It’s called “geo-engineering” and it’s a last-ditch attempt to stave off some of the worst case scenarios of climate change which loom larger than ever.

It’s not a way of avoiding the painful task of weaning ourselves off carbon – that must happen anyway – but it might buy us a bit of extra time, say the geo-engineering proponents.

It’s going to take decades to roll out the kind of green technologies

needed to replace our fossil fuel dependence, but we’re probably already committed to a dangerous 2°C rise in temperature, given how much accumulated greenhouse gases there are in the atmosphere at the moment.

The problem is that efforts to geo-engineer (basically retrofitting the over-heated ocean-atmosphere system) could unleash a beast as mean and uncontrollable as the one it was created to stop.

Shunting sulphate aerosols into the atmosphere – a “reversible” technique since they will work their way back out of the atmosphere after about a year – might keep some of the sun’s energy at bay, but it could also trigger a suite of other undesirable consequences.

“The sulphates would slow or reverse the recovery of the ozone layer,” reported Scientific American late last year, “they might also reduce global rainfall, and the rain that did fall would be more acidic.”

Worse still, many fear that any actions like this from one or more nations which trigger drought in another nation could be seen as tantamount to a declaration of war.

An article in the New Scientist points out that orbiting mirrors are less reversible and would need to be maintained for at least two centuries before being dismantled. By then, emissions would have to have been brought significantly down; otherwise runaway global warming would start as soon as the mirrors were gone.

As for super-fuelling the oceans with nutrients (iron filings), who knows what the consequences might be for marine systems? It is probably true that most fish don’t have much use for iron filings.

New Scientist magazine goes on to say that Geo-engineering, as sci-fi as it sounds, is not an excuse to continue business-as-usual with our wholesale emissions production. They’re calling it the world’s “Plan B”. And we only need a Plan B when Plan A isn’t working.


 
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