Bluefin fears

need to investigate the possibility of catastrophic side effects. At plan B level, there are several options that might help to remove CO 2 from the atmosphere. The idea of fertilising the oceans with iron in order to produce algal blooms gets poor marks. The results of Lohafex, a recent fertilisation experiment in the South Atlantic (Curr. Biol. 19, R143), have also suggested that the carbon removal effect would not be as significant as desired. MIT researcher Sallie Chisholm and colleagues have argued in a recent opinion piece in Nature (17 September 2009 issue, p. 347) that this option should be dropped. " We already know enough about how ocean systems function to say that iron fertilisation on large scales will be disruptive to ocean ecosystems and is unlikely to be effective for climate mitigation, " the authors conclude. Of the other carbon removal options assessed, the Royal Society report says, " none has yet been demonstrated to be effective at an affordable cost, with acceptable side effects. " However, the outlook for options like carbon capture and storage and enhanced weathering may improve if research and development efforts are upgraded. One essential ingredient that all climate management options (other than planting trees) have in common is the need for international agreement and governance. The report highlights this requirement as a challenge that is possibly even greater than the scientific and technical difficulties. Seeing that governments have so far failed to agree on a global strategy to reduce CO 2 emissions, what are the chances of agreement on removing CO 2 or blocking out sunlight? The report recommends that the political challenges involved with such measures " should be explored in more detail by an international body such as the UN Commission for Sustainable Development. " This, the report concludes, should happen simultaneously with improved international collaborative research to further evaluate the more promising options available to mitigate climate change. Michael Gross is a science writer based at Oxford. He can be contacted via his web page at www.michaelgross.co.uk Attempts to save the bluefin tuna from extinction suffered a serious setback last month when the European Union dropped its demand for commercial fishing of the species to be banned. Pressure from Mediterranean fishing nations, including Spain, Italy and France, blocked moves to get the European Union to support a worldwide ban, proposed by Monaco. The proposed ban had got the …