Science  03 Aug 2012:
Vol. 337, Issue 6094, pp. 508

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  1. Earth Keeps Sucking Up Greenhouse Gases

    Earth's oceans, plants, and soils suck up about half of the carbon dioxide humans put in the atmosphere by burning fossil fuels. Without these carbon sinks operating at their usual pace, the additional greenhouse gas would make global warming even stronger. But the warming itself could be throwing a monkey wrench in the works by stressing plants and slowing their uptake of carbon dioxide. Some researchers have in fact reported a worrying slowing of carbon dioxide uptake in one part of the globe or another.

    In this week's issue of Nature, however, a group reports that the planet's carbon sinks are on the whole doing just fine. The researchers calculated how much carbon has been going into sinks by subtracting the amount remaining in the atmosphere from the amount emitted over the past 50 years. In that time, global carbon uptake doubled to 5 billion tons per year—keeping pace with humans' growing input—so that about 55% of emissions continues to be stored. That's reassuring but says nothing about the future vitality of the world's carbon sinks.

  2. Flushing Out Drug Users

    During one week in March 2011, Kevin Thomas, a toxicologist at the Norwegian Institute for Water Research in Oslo, and colleagues collected daily samples representing 24 hours of sewage flow from 21 sewage treatment plants in 19 cities across Europe in order to find out how much of certain illicit drugs people in those cities consume. The samples were analyzed for traces of five different drugs.


    In the study, published in Science of the Total Environment, the researchers found that while cannabis consumption appeared to be similar throughout Europe, cocaine use per capita was highest in Belgium and other parts of west and central Europe, while methamphetamine levels per capita were highest in Scandinavian cities and Budweis in the Czech Republic.

    Some of the peaks may be due to drug production rather than consumption, Thomas cautions. Another source of uncertainty is that much is still unclear about drug metabolism in the body, says Fritz Sörgel, head of the Institute for Biomedical and Pharmaceutical Research in Nuremberg, Germany, who was not involved in the work. The authors assumed that on average, 38% of a cocaine dose is excreted. “How good that value really is still needs to be shown,” Sörgel says.