Illustration by Claudio Munoz

NOTHING about global warming is simple, alas. Meteorological models fry the circuits of the largest supercomputers. Feedback loops and anomalies turbocharge an ill-tempered debate about what will happen where and when. And don't even start on the politics of negotiating a global agreement on emissions or the intricacies of cap-and-trade.

Unfortunately, the technology of climate change is no simpler than anything else. A field that you may think is governed by level-headed, spreadsheet-wielding engineers is alarmingly prone to zealotry and taboos. Climate change is too important and too complex to yield to either.

It is seductive to think a new technology can solve your problems at a stroke. But zealotry has lately suffered a defeat. It used to be an article of faith in the motor industry that hydrogen-powered fuel cells were the green future, and companies spent billions of dollars on the technology. But it turns out that fuel cells have three Achilles heels (see article).

The first is the chicken-and-egg problem that, as there are virtually no hydrogen filling-stations, there are no hydrogen cars—and hence there is no reason to build the filling-stations. Then comes the cost of hydrogen-based vehicles. Just the platinum for the catalyst inside a fuel cell costs as much as an internal-combustion engine of equivalent power, according to a recent study. And producing hydrogen from natural gas creates a lot of carbon dioxide—about double what a small, petrol-based car emits. One day hydrogen may be produced from the electrolysis of water. But it would have to be transported and stored, which would require a new infrastructure.

So, for the next few decades, at least, technological pragmatism will rule motoring. More efficient internal-combustion engines will wring out mileage from every drop of fuel, and hybrid powertrains will combine an electric motor with a conventional engine. Soon there will be “plug-in” hybrids, which can be recharged from the mains and call on a petrol-powered generator when needed. The plug-ins, in turn, are a bridge towards all-electric vehicles. The plan mapped out by the car industry may not be as technologically elegant as the fuel cell, but it has the merit that it is based on technology that works, is not expensive and can use existing infrastructure.

Fire up the Bunsen burner

Elsewhere, however, the taboos still rule. Nowhere more so than in geo-engineering, the idea of combating global warming by altering the climate by, say, absorbing carbon dioxide in the oceans, or reflecting sunlight back into space (see article). This involves fantastic sounding schemes, such as fertilising the oceans with iron (to cause a bloom of planktonic algae, thus sucking carbon dioxide out of the atmosphere) or ejecting carbon from the poles using lasers. Scientists and policymakers have been reluctant even to discuss the subject—much less research it, because they worry that it could cause more problems than it solves and that it will give politicians an excuse to avoid curbing carbon emissions.

Both fears are reasonable. The farmer who introduced rabbits into Australia said the bunnies would do “little harm and might provide a touch of home, in addition to a spot of hunting.” The rabbit went on to become a devastating pest. And the world's politicians, they may well negotiate with less commitment if they feel that they may one day be let off the hook.

But neither reason should stop research as insurance. Some forms of geo-engineering may in fact turn out to be easier and cheaper than widespread global curbs on climate emissions—though they may still be unacceptably risky. Only research can tell. As for the politics, geo-engineering cannot just be put back in its box. And because research creates new information, it is as likely to disabuse those who think they can avoid climate-change agreements as it is to offer them false hope. Just ask the people who have given their lives to the fuel cell.

The solution to climate change will probably involve an array of technologies, from renewables, nuclear, carbon sequestration, public transport to energy conservation. It is too early to say whether geo-engineering or anything else will be part of this mix. Geo-engineering may turn out to be too risky, however much is spent on researching it. Then again, there may come a time when it is needed. The world needs to be ready—and research is the only way to prepare.