#Sow The Change

august, 2016

“Forged in the heart of aging stars, carbon is the fourth most abundant element in the Universe. Most of Earth’s carbon is stored in rocks. The rest is in the ocean, atmosphere, plants, soil, and fossil fuels.  Carbon flows between each reservoir in an exchange called the carbon cycle…. Any change in the cycle that shifts carbon out of one reservoir puts more carbon in the other reservoirs. Changes that put carbon gases into the atmosphere result in warmer temperatures on Earth.”

NASA Earth Observatory

I think our society struggles with the concept of “cycles”.  

Yes, cycles, and I don’t mean cycling, even though it’s an exciting sport especially now that everybody is well into the Olympic spirit.   

The Cambridge dictionary defines cycles as “a group of events that happen in a particular order, one following the other, and are often repeated”.

There are the cycles of life for example which take us a bit of time to get used to: adolescence, adulthood, older age, etc.).  Or the cycles in the garden that for the novice gardener are the first thing to get his/her head around: preparing the soil, planting, feeding, harvesting, preparing the soil again.  And of course there is the food cycle which is central to the mission of ZEA Hungry Goods:  soil, food, food waste, soil again.

But the cycle that is the purpose of this blog is the carbon cycle, which has been the central point and argument of some of my most recent discussions, especially from a climate change point of view.

This is an attempt to answer a question that many people have asked me in the last few weeks: “if we put carbon back into the soil can we ensure that it stays permanently there?”.        

The origin of this question comes from the concept of “permanence” which is a common concept in climate change projects specially when comparing “carbon sequestration projects” (e.g. reforestation or soil carbon projects) to “greenhouse gas emission avoidance projects” (e.g. renewable energy replacing fossil fuels). 

Although there is a debatable issue of “permanence” even in “emission avoidance projects”, that is not the purpose of this blog (e.g. the fact that we don’t burn a ton of fossil fuels today doesn’t guarantee that we may not still mine it and burn it later).  

The fact of the matter is this. 

Carbon sequestration projects, most of the time, rely on “living systems” (e.g. forests, soils, oceans, etc.). These systems operate in cycles rather than black and white inputs and outputs easily measured over the years.   By doing so, these projects have the enormous capacity to address climate change challenges in a more holistic fashion. 

For example, in the case of re-establishing the food cycle through composting by converting our food waste into fertile soil we are preforming the two types of projects mentioned above:  emissions avoidance and carbon sequestration.   The avoidance of greenhouse gas emissions is in the form of the avoided methane that the food waste would have released if it ended in a landfill instead of composted.  That is a settled argument and one that nobody would disagree with (although after seeing some of the most recent political debates on climate change here in Australia I wouldn’t be surprised if someone argues that sending food waste to landfills is actually “good for humanity”).

Now, “where the pig twists the tail” (as we say in Mexico), is with the issue of permanent storage of carbon when we use the compost to fertilize soils.   

Every living being on this Earth at some point is either a source or a sink of carbon.  Plants for example, store carbon through their biomass and release carbon through plant respiration. 

The soil, in this case, assists in the sequestration of carbon through the photosynthesis of plants which contributes to plant growth and microbial activity in the soil.  In turn, one day, plants will decay returning some carbon to the soil and some to the atmosphere which then will be used again by plants through photosynthesis.

Wow!  Hold on!  Oh! Oh! My head hurts!  It’s complicated! No, not really. 

The carbon cycle is not much different than the other great cycles that sustain life on this Earth.  For example, the Water Cycle.   If we put a drop in the ocean and give it a serial number, can we ensure that the ocean will forever capture that particular drop of water (and the hydrogen and oxygen in it)? Permanently?  Of course not.  That drop of water will eventually be evaporated, turned into a cloud, rain over a mountain, become ice, be melted in spring, come down as a river and get back to the ocean.    

Both, the carbon and water cycle, which are central cycles for life on Earth, maintain a constant exchange of elements shared between all living beings on this planet.   These elements are not “permanently” fixed in one place.  For these cycles to work they have to be in constant motion.  The problems begin when cycles come out of balance.  

To restore the balance of the carbon cycle is the most important issue here, at least from the Earth’s perspective.  The issue of “permanence” is helpful for us humans because we like to measure and quantify the impact of our actions.   

However, we have hit the carbon cycle very hard.  On the one hand we are producing enormous amounts of carbon by burning the fossil fuels pool while at the same time, by halving the topsoil in the world (the fertile part of our soils) during the last 150 years, we have limited the capacity of the soil to perform its function as a carbon pool.  Too much carbon in the atmosphere and too little capacity for the soils to capture this carbon.   

By returning the fertility to our soils with techniques such as composting, we contribute to bringing the carbon cycle back into balance and allow the soils to perform the magnificent function they were meant to perform as the second biggest carbon pool on Earth.  

Please watch the fantastic video from the organisation Kiss the Ground: The Soil Story.