Muddying the waters

system, " read Daily Mirror's account. " Scientists say up to 80 per cent of cases could be prevented by those at risk living in warmer areas. The UK and Canadian team found that vitamin D controls the gene known to increase MS risk. " The most prudent account was by Robin McKie in The Observer. He alone pointed out that the significance of vitamin D for health, and especially calls for more sunbathing, were controversial matters. On the one hand, he reported Gillie as advising people to sunbathe " far more frequently than currently advised ". But McKie also cited opposition from Cancer Research UK on the grounds that careless sunbathing was already leading to 9,000 new cases of melanoma, and 2,000 deaths, in Britain each year. The Observer article included a caution that the link between vitamin D deficiency and MS remained to be proven. " People with low vitamin D may be more likely to have MS, but this might happen simply because their condition makes it difficult to get out in the sunshine and make vitamin D in their bodies, " it quoted Cambridge nutritionist Inez Schoenmakers as saying. " We have yet to distinguish cause and effect in many of these cases. " George Ebers and Oliver Gillie may well be right. The evidence is persuasive. But whether a campaigner should be an anonymous author in this context is a disturbing question. We wouldn't be at all happy if a pharmaceutical industry lobbyist played such a role. The Severn estuary, which divides England from southern Wales, has the second largest tidal range in the world, so it seems a natural target to try to harvest tidal energy there, in one of the biggest potential projects to exploit renewable energy and help meet the UK's pressing renewable energy targets. But which way is best, and how seriously will it affect the environment of the estuary? The British government is currently canvassing views on such projects, in a consultation exercise running until April 23 (http:// severntidalpowerconsultation.decc. gov.uk), based on a shortlist of five possible projects — three barrages and two tidal lagoons connected to the shores. The maximum power could be gained from blocking off the delta near the cities of Cardiff and Weston-Super-Mare. The Cardiff–Weston barrage could generate around 8.6 GW of energy and contribute 5 per cent of the UK's current electricity consumption. The cost …