Biochar and Climate Change

Piers Watson recently posted an estimate of biochar’s potential impact on climate change on biochar.io, the Google Group for the international biochar community.

We post this information because it’s important to be realistic about biochar’s contribution to solving the climate crisis.

Hello Nando Breiter, Ian McChesney, Benoit Lambert, and Matthew Mayers:
I'm so happy to have some feedback, thank you!

My calculation goes like this:

According to the Carbon Dioxide Information Analysis Center - Conversion Tables (that is footnote 1 in my original message):
"1 ppm by volume of atmosphere CO2 = 2.13 Gt C"

Converting C to CO2 I divide 2.13 by 27.27% (or 3.666) and get 7.81 Gt CO2
So 1ppm is approximately equivalent to 7.81 Gt CO2
If I'm being optimistic my biochar is 85% Carbon and my production efficiency is 87% so:
converting C now to biochar is: 2.13 C divided by 85% purity divided by 87% efficiency and I get
(2.13/85%)/87% = 2.88 Gt biochar (similar to Ian's reply below)

So It seems to me 1ppm = somewhere in the region of 3 Gt biochar (depending on just about everything, of course)

And then yes, if you extrapolate out to what is needed to get even to 350ppm let alone 280, the problem is, as you say, pharaonic indeed!

I now know when I ran a solar program in London in the early 2000's we were massively under estimating the problem. I can't help but think we still are.

Thank you for your replies!
PW

The “footnote 1” reference is https://web.archive.org/web/20170118004650/http:/cdiac.ornl.gov/pns/convert.html

Note that assumptions are included in this estimate due to variability in biochar feedstock and in the conditions under which it is produced (primarily temperature and residence time).

Clearly, biochar will not erase the impact of the Industrial Revolution. It should be seen as part of the climate solution, which also includes ending fossil fuel combustion and rebuilding biological carbon reserves (primarily vegetation and soil) globally.