Opinion - Taking the long view on the world's energy supplies

            BACK in 1896, the Swedish scientist Svante Arrhenius realised that by burning coal we were adding carbon dioxide to the air, and that this would warm the Earth. But he mentioned the issue only in passing, for his calculations suggested it would not become a problem for thousands of years. Others thought that the oceans would soak up any extra CO₂, so there was nothing much to worry about.

That this latter argument has persisted to this day in some quarters highlights our species' propensity to underestimate the scale of our impact on the planet. Even the Earth's vast oceans cannot suck up CO₂ as quickly as we can produce it, and we now know the stored CO₂ is acidifying the oceans, a problem in itself.

Now a handful of researchers are warning that energy sources we normally think of as innocuous could affect the planet's climate too. If we start to extract immense amounts of power from the wind, for instance, it will have an impact on how warmth and water move around the planet, and thus on temperatures and rainfall (see "How clean is green?").

Just to be clear, no one is suggesting we should stop building wind farms on the basis of this risk. Aside from the huge uncertainties about the climatic effects of extracting power from the wind, our present and near-term usage is far too tiny to make any difference. For the moment, any negative consequences on the climate are massively outweighed by the effects of pumping out ever more CO₂. That poses by far the greater environmental threat; weaning ourselves off fossil fuels should remain the priority.

Even so, now is the time to start thinking about the long-term effects of the alternative energy sources we are turning to. Those who have already started to look at these issues report weary, indifferent or even hostile reactions to their work.

That's understandable, but disappointing. These effects may be inconsequential, in which case all that will have been wasted is some research time that may well yield interesting insights anyway. Or they may turn out to be sharply negative, in which case the more notice we have, the better. It would be unfortunate, to put it mildly, to spend countless trillions replacing fossil-fuel energy infrastructure only to discover that its successor is also more damaging than it need be.

These climatic effects may even be beneficial. The first, tentative models suggest that extracting large amounts of energy from high-altitude jet streams would cool the planet, counteracting the effects of rising greenhouse gases. It might even be possible to build an energy infrastructure that gives us a degree of control over the weather: turning off wind turbines here, capturing more of the sun's energy there.

We may also need to rethink our long-term research priorities. The sun is ultimately the only source of energy that doesn't end up altering the planet's energy balance. So the best bet might be to invest heavily in improving solar technology and and energy storage - rather than in efforts to harness, say, nuclear fusion.

For the moment, all of this remains supposition. But our species has a tendency to myopia. We have nothing to lose, and everything to gain, by taking the long view for a change.

http://www.newscientist.com/