Trees. A few comments to this blog have championed them as the easy (and sometimes only) answer to our greenhouse gas problem. Unfortunately, the burning of fossil fuels puts much more carbon dioxide into the the air each year than the Earth's current stands of trees and plants and swaths of algae take in for photosynthesis.
Making trees even less likely as a sole climate change solution is that we cut them down a lot; more than 50,000 square miles of forest each year, according the the UN Food and Agriculture Administration.
But what if we began growing trees genetically modified to absorb and store more carbon dioxide?
That's what an article published last week in the journal BioScience asks. The authors, from Lawrence Berkeley and Oak Ridge national laboratories, haven't exactly determined how to genetically engineer these trees, but offer strategies for doing so.
For instance, they roughly estimate plants could sequester 2 gigatons of carbon if they were genetically engineered to absorb more sunlight, store more carbon in their root systems, or send more carbon to the forest soil for sequestration.
Hypothetically, let's say these future photosynthetically-enhanced trees are ecologically sound, not invasive Frankentrees with blue trunks and purple leaves. Then what? Convince nations to replant entire forests they've already cut down or find new land currently not in use? Perhaps a desert? (One strategy the scientists propose is strengthening a tree's ability to survive in places or conditions it normally couldn't, such as making it more drought-resistant.)
The researchers don't suggest GMO trees as a global warming cure-all but as one of many tactics. Part of an issue devoted to assessing the potential for sequestering carbon biologically, the article also discusses improving the biomass quality of plants used for biofuels. They write that engineering the plants to synthesize more lignin, tannins, and other compounds in their roots than in stems and leaves would sequester more carbon while lessening the processing involved in preparing the above-ground plant matter needs for biofuel production.
While some of the study's strategies may lead to more promising solutions than others, the practical considerations over GMO forests are significant. Makes better sense to focus on keeping the natural ones we have.
Images: Flickr_Tim Proffitt-White and SeaWiFS Project, NASA/Goddard Space Flight Center/ORBIMAGE