Carbon sequestration.. the buzzword of the last few years, been thrown in here and there in various conversations..
Sometimes for good reasons, other times just for fancies..
let's start with the basics..
What really is Carbon sequestration?
First of all, let me clear some terms for the beginners out there, I am sure you have all heard a lot of it, but just to all be on the same page, by carbon sequestration I mean the long-term removal, capture or sequestration of carbon dioxide from the atmosphere.
Now, if we think about removal from the atmosphere: natural life on this planet (well on the surface of this planet, and not deep down in the oceans) is based upon photosynthesis. Plants do it. And with them other photosynthetic organisms such as micro and macro algae. What is photosynthesis? Just as a reminder for those who didn’t do well at school in biology: during the day, when light is available, plants take up co2 from the atmosphere and release o2 (At night they respire, so they release some co2, something to be mindful about - more on this later). Technically, though, also us animals sequester co2, not directly from the atmosphere, but from what we consume - but we would prevent it from going back out in the atmosphere. All ‘mass’ is basically a form or another of carbon atoms. Since, matter is neither created nor destroyed, the C atoms are bound to be coming from somewhere. If it’s in our mass it’s not in the atmosphere. So yes, when we take in O2 and release CO2 respiring we are respiring mass out (out of topic but yes, this is the principle behind losing weight - check this great and inspiring ted talk ) . And so on.. we read that whales are sequestering carbon ( and it’s also published on the IMF ) , or hear on the BBC podcast ‘people fixing the planet’ that also jellyfish have power to be carbon sequestering
And at that point.. I really want to scream that, if we follow this logic, then everything is and that perhaps we are just abusing this buzzword…
What are the problems with abusing carbon/CO2 sequestation?
Well, I am a scientist and I like theories like these. Moreover, I love nature, so really everything that can be done to preserve it.. I want it done.
But.. there is always a but!
And this ‘but’ is that we really don’t yet have a thorough, full, understanding of basic things
For example, as I mentioned before, plants also respire at night, and just a couple of years ago it was discovered that plants emit 30% more than previously thought during this process , this means, their carbon storing potential is lower (still high, but lower..).
And more. We need to stick to the definition and consider the ‘long term’ sequestration potential. For example, for whales there may be a point since they sink to the seabed..but.. most of it in reality is eaten, from the water column, to sediment surface to microbes.. and that goes for a lot of other things that lately we are starting to call as ‘sequestering’ organisms.. can we really consider it sequestration if it moves up in the food chain and likely leaking back in the atmosphere (through ‘breathing’ aka ‘catabolism’)
There are also other processes going on, with associated microbes contributing to fluxes of other green house gases (such as nitrous oxide and methane, which have much bigger green house gas effects compared to co2!) - and those are very location dependent and frankly we still don’t know that much about. There is plenty of research going on, but not enough, as most things in ecology are context dependent. And there is an argument that perhaps we should start studying these things following the same protocols, with the same timelines, same units of measurements if we want to come up with unifying theories. Otherwise, it's all wasted effort.
There is also a big debate on shellfish, and well here we are entering into my area of research and expertise - and also here we don’t know. It’s not that there is not enough research about it, it’s that once again, research, as such, might not have a global ‘fit all’ solution. So we know that shells are made of calcium carbonate, and that an animal makes quite a lot of shell, and so they have been deemed for a long time as a ‘carbon sequestration tool’, well, that was until some scientists challenged that and reminded everyone that to form the calcium carbonate there is also co2 being emitted. But it is not that simple, as the co2 emitted depends upon the chemistry of the surrounding water. Plus, they respire in their lifetime. I have been reading a lot of studies and most have discordant results. Aside that as scientists we ought to put more effort into being consistent with our calculations, as, once again, a lot of the discordance depends on how these fluxes are calculated.
The point I want to make is that the truth is that we are still miles behind knowing how to use nature to slow down the green house effect..
So why are we banking on it so much?
Simple, because it’s easier to keep going in the same direction and hoping for a magic solution
Sad truth. No magic solution exists!
Only positive outcome ? We will have more nature
And that can only be a good thing
Catch up on thecarbon market here
and the CO2 tax here
Definitely recommend watching this great video about the researchers who proposed the power of trees and reforestation as co2 sinks
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