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6 | NewScientist | 14 August 2010 SUPERSTOCK CRUNCH time for the Kyoto protocol is fast approaching. 2012 marks the end of the two- year period during which rich nations must prove that they have cut emissions from 1990 levels. That may be an impossible task. The problem lies with error bars. Matthias Jonas at the International Institute for Applied Systems Analysis in Laxenburg, Austria, has calculated that countries can only report their emissions to within 5 to 10 per cent of what they actually emitted (Climatic Change, DOI: 10.1007/ s10584-010-9914-6). This is because there is no direct way of measuring how much carbon dioxide, say, a country emits. Instead, nations must estimate their emissions indirectly, by totting up the amount of coal and oil that was burned to power their industry and transport Kyoto count up sectors, for instance. Each of these estimates necessarily comes with big uncertainties. Yet the European Union, which promised the biggest cuts by 2012, must reduce its emissions by 8 per cent relative to 1990 levels. That’s less than the error bars, so it will be near impossible to say whether it, or any other nation, have met their commitments. “The significant uncertainty in greenhouse gas emissions needs to be tackled,” says Euan Nisbet of Royal Holloway, University of London, who coordinates the EU’s methane monitoring programme. Miscarriage delay HOW long should a woman who has had a miscarriage wait before trying to conceive again? The World Health Organization suggests six months, but it seems women might be better off trying again as soon as they want to. The WHO guidance is based on a South American study that found more adverse outcomes in women who conceive early. Now Sohinee Bhattacharya at the University of Aberdeen, UK, and colleagues have analysed Scottish hospital records of 30,000 women who miscarried between 1981 and 2000. Those who became pregnant again within six months were less likely to experience another miscarriage or an ectopic pregnancy than those who waited more than six months (BMJ, DOI: 10.1136/bmj.c3967). The new study suggests there is no physiological reason to delay pregnancy after miscarriage, says Bhattacharya. Cicely Marston of the London School of Hygiene and Tropical Medicine, who co-wrote the WHO guidelines, describes the study as exciting. “The guidelines are due for a revision,” she says. Chemical concern LEVELS of a controversial anti- bacterial additive present in the urine of people in the US jumped by over 40 per cent in two years. Last week the Centers for Disease Control and Prevention published data on the levels of 212 chemicals in 2400 volunteers in the US. The average amount of triclosan, a chemical added to soaps and toothpastes to kill fungi and bacteria, had increased from 13 micrograms per litre of urine –If the loggers don’t get you…– –Sensible, but is it safe?– Forest double whammy BY THE end of the century, up to 82 per cent of today’s tropical forests could be damaged by a combination of climate change and local destruction. Gregory Asner of Stanford University in California, and colleagues, tried to calculate where the effects of climate change, logging and other causes of deforestation will impact upon forest ecosystems. They ran 16 different climate models up until the year 2098 and used a vegetation model to work out which types of plants could survive in each area. The team assumed that deforestation and logging would continue at a rate similar to that between 2000 and 2005. In some areas, the effects work separately. For example, in South America, climate change strikes hard in the north-east while deforestation hits the south-east. But in the central Amazon, both effects combine to devastate forests (Conservation Letters, DOI: 10.1111/j.1755-263X.2010.00133.x). Asner says these patterns present both a challenge and an opportunity. “In regions with a lot of land-use change but low projected climate change, new protected areas could be established,” he suggests. “The basic method is very sound,” says Yadvinder Malhi of the University of Oxford, though he is cautious about the numbers coming out of the model. He also worries that if people think a region is doomed by climate change, they might decide to go ahead and log it. “There’s a danger of a perverse reaction,” he warns. “Countries can only report their emissions at best to within 5 to 10 per cent of what they actually emitted” PATRICK DE WILDE/JACANA/EYEDEA/CAMERA PRESS UPFRONT
