Could better soil management reverse global warming?
Last week I attended the 3rd Annual Climate Adaptation for Farmers conference, hosted by Abundance North Carolina. The main focus, as the conference title suggests, was on how farmers can adapt and survive in a changing climate.
Time and again, however, speakers emphasized an interesting and powerful fact:
The very things we need to do to adapt to a changing climate are exactly the same actions we need to take to slow down, or even reverse, global warming in the first place.
During his keynote, Peter Bane—author of The Permaculture Handbook—made this astounding statement: Better farming could not just slow, but reverse, the buildup of atmospheric CO2. Noting that rock star farmer Joel Salatin of Polyface Farms has built up 6.5% of additional carbon in his soils, Bane argued that truly maximizing soil carbon sequestration across all the world's agricultural soils could literally soak up more carbon than we release each year.
Other estimates on soil carbon sequestration are more conservative, with acclaimed soil science professor Rattan Lan suggesting something closer to 10% of annual emissions may be a more realistic figure. Meanwhile a recent report from the Union of Concerned Scientists entitled Halfway There suggests that reforming the entire land use sector, including croplands, forestry, pastures and restoring degraded lands could deliver half of the emissions cuts needed to keep warming below 2 degrees centigrade.
I am by no means a soil scientist. (And neither is Peter Bane.) So I am not going to try to parse through the various projections, or determine the "true" amount of carbon dioxide we could sequester in the soil. Instead, I'll offer this very simple fact:
We could do a whole lot better than we are doing now. And doing so would be a win-win situation, even if we don't take carbon sequestration into account.
In cultivating our ability to "farm carbon," we would simultaneously be reducing our reliance on fossil fuels and chemical fertilizers, increasing our farm lands' ability to retain nutrients and hold water, we'd be mitigating flooding and protecting against drought, and we'd be enhancing biodiversity too. There's even some research to suggest that small-scale agroecology could increase yields compared to conventional farming.
What's not to like?
In fact, Peter Bane was so convinced of the role that soil will play in the fight against climate change, he offered this powerful—if probably controversial—proposal (I am paraphrasing from memory):
"As long as people are going to continue to drive big cars, live in big houses, and fly around the world, we have to tell them that eating organic and sustainable is not only advised. It's compulsory."
We do have to do something to clean up our own messes. And farming seems as good a place as any to start.
For folks who enjoyed my piece on gardens and carbon sequestration, Peter Bane offered this practical advice on enhancing carbon storage: engineer "soil climaxes", and lots of them—meaning we need to grow plants, be they cover crops, annual food crops, or perennials, trees and shrubs, and then we need to cut them back before they flower. As plants get cut back, their roots die underground, leaving packets of food for the underground food web. And that food turns into guess what? Soil carbon.
For more on the fascinating interaction between soil and climate, I highly recommend The Soil Will Save Us by Kristin Ohlson. And in the meantime, we'd probably best build some gigantic solar farms too.
Let's get to work.