In the world of greenery, no good deed goes unpunished

though it be, sulphur is, from one point of view, a pretty green product as well. Its principal source, providing more than 80% of the total made, is compounds derived from refining oil and gas, which would otherwise go to waste. Left , these would gum up catalysts and also burn to form sulphur dioxide, a notorious pollutant that causes acid rain. Instead, their sulphurous contents are used in the vulcanisation of rubber, to make preservatives for foods and as ingredients of soap. They are also turned into sulphuric acid, a chemical of great industrial importance that is used, among other things, in the manufacture of fertiliser.The irony of all this, pointed out in a paper just published in the by Mark Maslin and his colleagues at University College, London, is that, as demand for oil and gas drops in response to the climate-change-induced energy shift currently going on, sulphur produced this way will become less available. Yet this is happening at a moment when demand for the element is increasing.