Last month, SciDev.Net reported on a study highlighting the need for international regulation of geoengineering field trials, which said that scientists around the world conduct this research in a legal vacuum.
It’s easy to see why geoengineering is attractive to scientists. Finding a technological fix for climate change is a nice, big, juicy project, with lots of scope for lucrative research applications and the chance of a place in the pantheon of scientific greats or even a Nobel Prize. And from the point of view of diplomats too, at a time when climate talks are in trouble, it is tempting to hope for a solution that avoids excessive negotiations.
As an illustration, a study published last week by researchers from the University of Reading, UK, suggests that large geoengineering efforts could have side effects that would disproportionately harm the globe’s poorest people.  It argues that a massive injection of sulfate particles into the upper atmosphere may well lower average global temperatures by reflecting sunlight, but this could also cause huge changes to rainfall patterns around the equator — with potentially devastating impacts for poor people.
Andrew Charlton-Perez, the lead author of the study, said in a statement: “We have shown that one of the leading candidates for geoengineering could cause a new, unintended side effect over a large part of the planet. A reduction in tropical rainfall of 30 per cent would, for example, quickly dry out Indonesia so much that even the wettest years after a man-made intervention would be equal to drought conditions now.”
Here is an example of where society should employ the precautionary principle, the basis of European legislation regarding environmental protection.
According to one definition, “the essence of the principle is that, in the absence of firm scientific evidence as to the effect of a particular substance or activity, the protection of the environment should be the first concern. There is no need to wait for conclusive scientific proof before preventive action is taken. The environment as a whole should be given the benefit of the doubt.” 
The work of Charlton-Perez and his colleagues shows how science can be a double-edged sword, with potential to solve problems, but also to do great harm. So rather than hope for a high-tech solution to climate change, I would invoke the precautionary principle, concentrate on sustainable development for the poor and the negotiation of robust climate change agreements.
Roger Williamson is an independent consultant and visiting fellow at the Institute of Development Studies at the University of Sussex, United Kingdom. Previous positions include organising nearly 80 international policy conferences for the UK Foreign Office and being head of policy and campaigns at Christian Aid.
 Angus J. Ferraro and others Weakened tropical circulation and reduced precipitation in response to geoengineering (Environmental Research Letters, 2014)
 Jeremy Stranks The A-Z of the environment (Thorogood, 2007)