• Dick writes about Earth and planetary science for Science magazine.

ScienceShot: Earth Keeps Sucking Up Greenhouse Gases

1 August 2012 1:00 pm

To the planet's benefit, Earth's oceans, plants, and soils suck up about half of the carbon dioxide we humans put into 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 into the works—by stressing land plants and slowing their uptake of carbon dioxide, for example. Some researchers have in fact reported a worrying slowing of carbon dioxide uptake in some parts of the globe. But in a study published online today in Nature, a group finds that the planet's carbon sinks are on the whole doing just fine. The researchers calculated how much carbon has been going into sinks (black line) by subtracting the amount remaining in the atmosphere (blue line) from the amount emitted (red line) over the past 50 years. During that time, global carbon uptake (a negative value here) doubled to 5.0 billion tons per year. That growing uptake by sinks kept pace with humans' growing input so that about 55% of emissions continue to be removed from the atmosphere. That's reassuring, the team reports, but it says nothing about the future vitality of the world's carbon sinks.

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