"Crutzen proposed a method of artificially cooling the global climate by releasing particles of sulphur in the upper atmosphere, which would reflect sunlight and heat back into space. The controversial proposal is being taken seriously by scientists because Professor Crutzen has a proven track record in atmospheric research.
"A fleet of high-altitude balloons could be used to scatter the sulphur high overhead, or it could even be fired into the atmosphere using heavy artillery shells
"In his forthcoming scientific paper, Professor Crutzen emphasises that the best way of averting global climate disaster is for countries to cut back significantly on their emissions of greenhouse gases, notably carbon dioxide produced by burning oil, gas and coal. But in the absence of such measures, and with the average global temperature expected to rise more than 3C this century, there may soon come a time when more extreme measures have to be considered, he said."