Thursday, September 18

Uh-Oh: Heat Waves Reduce Carbon Uptake

Turns out carbon sinks don't work so well in hotter weather, and woops: isn't that just what's in our planetary forecast?


In research published in Nature on Wednesday, scientists have found that plants and soil can take up to two years to recover from heat-waves, greatly reducing their carbon uptake.

The scientists carved out miniature eco systems in chambers about 8 feet by four feet with their plant communities and soil intact,in such a way that light, darkness, temperature and rainfall could be carefully controlled and levels of CO2 monitored.

They based the experiment on data from 150 years of weather history at the site, to duplicate heat-wave years, when temperatures had been between 2 and 7 degrees hotter, but without drought.

Over the next four years, two of the four plots were exposed to a sudden rise in temperature during the second year of the experiment, a hike of almost 8 degrees Fahrenheit. The other two were the control group, and programmed to reproduce the weather conditions of the original site based on data recorded over the previous seven years.

Arnone's team found that during this anomalously warm year and the year that followed, the two plots in the simulated heatwave conditions sucked up two-thirds less carbon than the ones that had been exposed to normal temperatures.

This is bad news for us, coming on the heels of related study published last year, one finding that carbon is no longer being stored by soil and the other, finding that the ocean's carbon sink is in decline.

This study reverses earlier findings published in 1999, that warming stimulates carbon storage at the ecosystem level, that were the basis for international carbon offset projects.

As a result, these findings throw in a new factor for calculating the value of natural sinks, which play a critical role in offsetting carbon emissions.

This is critical information, as this kind of calculation is used in deciding whether to fund forestry projects for use as carbon offsets rather than new clean energy projects such as wind farms. It is good news for wind farm funding, and that's great, but still, it is more scary news for our species overall.

Photo by TexasFinn
Via Terra Daily

For Matternetwork