At the Ecological Society of Australia Conference this week, I watched a talk about a study measuring the above and belowground biomass of some low-rainfall tree species. They touted the importance of this research as vital for the wider aim of carbon sequestration. This got me wondering... How valid a solution carbon sequestration is for approaching climate change?
A quick description for those unfamiliar with this concept. Carbon sequestration is the idea that atmospheric CO2 can be removed by capturing it in newly growing plants (or possibly other ways, but this is the most popular). So, the idea is, that if we plant enough trees, we could help to curb the dramatically increasing concentration of CO2 warming the Earth.
How feasible is this? So after some dredging of the internet, I came across a paper that quantifies the amount of carbon sequestered in a Manchurian Ash forest. This is a hardy, easily cultivated tree from northern China, and out of the species covered in the paper, it seemed to suck up the most carbon, quickly. Then I dug up this cool figure showing a variety of carbon emission ‘scenarios’ from the IPCC report for policy makers. And yes, you're reading that axes correctly. The unit on the y-axis is gigatonnes. Yes, freaking, gigatonnes (aka. the weight of one billion elephants according to the old, analogy used by your elementary school teacher to conceptualize a ton).
After some huge assumptions and shoddy calculations, the best case scenario provided by the IPCC (the green section on the graph) could be offset if every one of the 7 billion people in the world were to plant about 100 trees and make sure to keep them alive for at least 20 years before cutting them down. Of course, don’t burn them or let them rot... Then the CO2 will be back! Well, that level of action would just about do it. But let’s be honest… that’s pretty improbable considering the fact that most of the world's population lives in cities, and thus doesn't have space to plant 100 trees.
Well, that brings me to my second dodgy calculation. Is there enough room for all these trees? If you use the same Manchurian Ash data, you would estimate that about 2 billion hectares of land need to be transformed to mature ash forest over about 50 years to bring atmospheric CO2 back to 1990 levels. Wellllll.... considering that most of the earth is water... ice.... desert... cities... or already a forest, this also starts to look not-to-feasible. However, according to this old National Geo article almost 6 billion hectares are dedicated to agriculture, over half of which is purely for livestock. So, this leads me to the extreme conclusion that if everybody became a vegetarian, or actually, if we just cut our livestock rearing in half, we would have enough free land for forest conversion to significantly reduce our carbon footprint.
Ok, there's a lot of flaws in this logic, like... many locations on earth will not support the types of forest that would sequester this much carbon, this is assuming that we are already following a huge reduction in our carbon dioxide production ("good" IPCC scenarios), and actual growth of many forests (not to mention economic market reactions or international collaborations) would take many years to reach maturity, possibly too late to mitigate many consequences of climate change.
HOWEVER, fact of the matter is, on a large scale, changes in human behavior could have a significant impact on this seemingly unsolvable problem. So, you know, go out... plant a tree... or 10. And try to cut your meat intake by at least half. Then tell all your friends to do the same.
Australian vocab:
stubbie holder: not as dirty as it sounds, this little guy holds a stubbie (a fat beer bottle). You may know it as a beer coozy. (ex: "I snatched up a few of those free stubbie holders at the conference to keep my Coopers cold this weekend. I hear it's gonna be 37!")
budgy smuggler: as dirty as it sounds... a speedo. A budgy, for the record, is a little parakeet. (ex: "You should never try to use a budgy smuggler as a stubbie holder, or vice versa")
Yay, less meat! Oh and more trees!
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