The silver bullet solution to climate change in many people's book is to simply 'plant a tree'. A recent study indicates that it might not be quite that simple...

The ability of forests to soak up man-made carbon dioxide is weakening, according to an analysis of two decades of data from more than 30 sites in the frozen north.

The finding published today is crucial, because it means that more of the CO2 we release will end up affecting the climate in the atmosphere rather than being safely locked away in trees or soil.

The results may partly explain recent studies suggesting that the amount of CO2 in the atmosphere is increasing faster than expected. If higher temperatures mean less carbon is soaked up by plants and microbes, global warming will accelerate.

... The surprise rethink concerns abundant evidence from around the world that winter is starting later and spring earlier. In northern latitudes, spring and autumn temperatures have risen by 1.1C and 0.8C respectively in the past two decades. That means a longer growing season for plants, which scientists thought should be a good thing for slowing warming....

The team focused particularly on the date in autumn at which the forests switched from being a net sink for carbon into a net source. Instead of moving later in the year as they had expected, this date actually got earlier - in some places by a few days, but in others by a few weeks. -- Guardian

If the report is correct, this is a major additional feedback loop that has the potential to greatly accelerate climate change.

The most obvious solution in the battle against global warming, of course, is to significantly reduce the amount of fossil fuels getting pulled out of the ground and burnt (i.e. reduce greenhouse gas inputs into the atmosphere). Another is to utilise more powerful carbon sinks (i.e. increase greenhouse gas extraction from the atmosphere). There is one change we can make in our way of working that would accomplish both! Although trees might not be keeping up, there are still armies of plants and organisms waiting to lend a hand -- if only we'd utilise them. I'm referring, in particular, to moving towards more sustainable agriculture.

Twenty-three years of ongoing research at The Rodale Institute Experimental Farm already provides strong evidence that organic farming helps combat global warming by capturing atmospheric carbon dioxide and incorporating it into the soil, whereas conventional farming exacerbates the greenhouse effect by producing a net release of carbon into the atmosphere.

The key lies in the handling of organic matter (OM): because soil organic matter is primarily carbon, increases in soil OM levels will be directly correlated with carbon sequestration. While conventional farming typically depletes soil OM, organic farming builds it through the use of composted animal manures and cover crops. -- New Farm

The world's soils are the earth's second largest carbon sink (next to the oceans). As we've shared before, proper soil management is a powerful and highly effective method of removing carbon from the atmosphere, as well as reducing fossil fuel use, reducing toxic chemical use and runoff, improving plant (and thus human) health, and more (actually, a lot more if we also simultaneously incentivise the relocalisation of our markets).

A couple of fast facts on this to drive the point home:

• Converting the U.S.'s 160 million corn and soybean acres to organic production would sequester enough carbon to satisfy 73 percent of the Kyoto targets for CO2 reduction in the U.S.
• U.S. agriculture as currently practiced emits a total of 1.5 trillion pounds of CO2 annually into the atmosphere. Converting all U.S. cropland to organic would not only wipe out agriculture's massive emission problem. By eliminating energy-costly chemical fertilizers, it would actually give us a net increase in soil carbon of 734 billion pounds. - Portland Independent Media Center