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The Compost Pile, Issue #004 -- Soil Carbon, CO2, and a Movie
September 21, 2020
Too much Carbon in the Air and Too Little in the Soil
“If you have not discarded a firmly held belief in the past 12 months … check your pulse. You may be dead…” from South Africa via Dr. Christine Jones
Well we are certainly living in interesting times. And to be honest some of the things I thought I knew for sure I now think are perhaps not completely wrong but neither are they completely right.
“It may be that when we no longer know what to do - we have come to our real work and that is when we no longer know which way to go we have come to our real journey.” Wendell Berry Let’s start with the looming crisis of climate change. And let’s see how soil plays a part here.
Watching the saw toothed climb of CO2 levels in the atmosphere coupled with rises in temperatures and an explosion of extreme hydrological events - I’m talking droughts, floods, hurricanes, wild fires etc. - is scary.
Here’s something extra scary. CO2 is a very long lived greenhouse gas. Like 500 - 1000 years long lived. Were we to completely eliminate all fossil fuel emissions today - and that would take a very magical set of circumstances given the global squabbles over who commits to what and who doesn’t - CO2 levels would continue to rise for a decade or two.
It’s enough to send a girl to bed in a deep depressed funk.
“95% of the heat dynamics of the blue planet are governed by water.” Walter Jehne, Soil Microbiologist
As depressing as that might be sometimes you just need to view the whole chaotic climate issue and debate from a new perspective. Walter Jehne, a soil microbiologist from Australia really helped me reframe our climate problem in a new way that actually gives us something we can do that actually will help.
The big greenhouse gases are CO2, methane, and NOx (nitrous oxides). Of these CO2 and NOx are very long lived while methane is much shorter lived. However the elephant in the room, the greenhouse gas that accounts for 80% of the greenhouse effect, is actually water vapour.
In fact according to Walter, he calls it Climatology 101, 95% of the heat dynamics of the planet are governed by water. And the issues we are experiencing related to climate are to a large extent water related.
The thing is water vapour is so variable it’s pretty much impossible to model. It varies from season to season, day to day and place to place. Carbon Dioxide is way easier to measure and we can clearly see that as CO2 levels rise things run amuck. Ergo CO2 levels, particularly fossil fuel emissions are the root cause of our problems.
But maybe we need to shift a tiny bit here. Maybe the issue is less the rise of CO2 levels in the air, and more the fall of Carbon levels, specifically the destruction of the soil carbon sponge, in the soil.
Since agriculture began we’ve been busy using methods that tend to reduce the carbon levels in our soils. And with industrialization of agriculture we’ve gotten faster at tilling the soil, using synthetic fertilizers, and biocides, soil carbon losses have accelerated. In fact we’ve lost as much as 70% of the soil carbon from our agricultural soils. And guess what. Soil carbon is critical to the water cycle.
So as carbon levels have been rising in our air they’ve been falling in the soil. And as soil loses its carbon, it loses what is known as the soil carbon sponge. Without the sponge it has trouble both infiltrating water into the soil and storing it in the soil. In other words the small water cycle is damaged.
When water can’t soak into the soil it runs off into streams, rivers and eventually to the sea. Aquifers don’t recharge. The soil dries out. And we have a vicious cycle.
Hope by Restoring the Soil Carbon Sponge
We’ve focused almost exclusively on eliminating and reducing fossil fuel emissions in our attempt to fight climate change. And trying to get the whole global community to commit to reducing those emissions seems to erupt in fights country to country, economy to economy and willingness to really double down is faint.
And truth be told it isn’t going to have an effect in the short term. It sends us down a black hole of despair as we watch our leaders squabble over the economy as the planet alternately floods and burns.
What if we focus as citizens, as individuals and small groups on restoring the soil carbon sponge. It’s very possible to do on just about any scale. Compost helps but it’s not the linchpin I thought it was. The linchpin appears to be green plants doing their thing with photosynthesis.
A new movie comes out tomorrow, that’s September 22, on Netflix. Kiss the Ground. I have not yet seen it but it promises to be good and I believe it will give us all something to think about, a few cherished beliefs to retire. A bonus it’s narrated by Woody Harrelson. Let me know what you think.
And Happy Composting Cheers Leslie
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