Exploring biocarbon: The road less traveled in climate policy

Guest Blog | November 26, 2013 | Energy Policy

This blog is the first in a series on biocarbon tools and strategies for climate mitigation.

How are we going to repair the changed climate?

Seriously, how are we going to un-do the damage already done? The amount of carbon dioxide (CO2) in our atmosphere (400 parts per million or ppm) is well beyond the 350 ppm that scientists agree is needed “if humanity wishes to preserve a planet similar to that on which civilization developed and to which life on Earth is adapted.” (Dr James Hansen, 2008.)

Why is 400 ppm a concern? Why must we get back to 350 ppm? Read more here.

We’ve already overshot, which means not only must we stop emitting greenhouse gases (GHGs), but we must also begin actively removing CO2 from the atmosphere and putting it somewhere safe.

A simplified version of the carbon cycle in vegetation and soil. Plants take CO2 from the atmosphere to synthesize tissue (plant biomass). As long as biomass is growing it accumulates carbon. During decomposition of dead biomass and humus the carbon is released as CO2. Image credit, Christoph Steiner, 2008.

How about the soil?  That’s a safe place for carbon.  This is the advice from Dr. Rattan Lal of Ohio State University.  He points out, since we humans began the agricultural revolution, world soils have lost between 25% to 75% of their original soil organic carbon (SOC).  What many of us do not sufficiently recognize is that we can put that carbon back.

And fortunately, when we put carbon back in the soil, other good things tend to happen: Erosion slows, drought resistance improves, nutrients tend to remain in the soil, and net plant productivity increases, allowing for more food production for a growing global population.

So how do we do it?

We all know we’ve got to stop burning coal and petroleum and other dirty fuel sources. Yes, we’ve got to radically improve efficiency and reduce waste of energy. Yes, we must continue to grow solar and wind and other renewables. But these measures cannot remove the carbon pollution already put in the air by our parents and grandparents.

In April of 2012, volunteers with Green Forests Work helped plant new trees on the site of the crash of Flight 93.

Let me be clear: To get back to 350 ppm, we’ll have to run the whole carbon-spewing machine backwards, sucking carbon out of the atmosphere and storing it somewhere safely. Typically, energy and climate policy analysts suggest afforestation and biomass carbon capture and storage (BECCS).

But these are only two of many tools available in the toolkit to restore carbon to the biosphere.

Hmm, biosphere plus carbon. Let’s call it biocarbon, shall we?

Thankfully, there are many more biocarbon strategies than just afforestation and CCS that can help suck up excess carbon pollution and bring CO2 in the atmosphere back down to an acceptable level.

Agriculture in the Southeast plays a huge role on the landscape, and in emissions of greenhouse gases (like nitrous oxide from cropland, or methane and ammonia from animal manure). Different ways of farming (sometimes called “sustainable agriculture” or “carbon farming”) can actually reduce these emissions while also improving the soil – in part by increasing the amounts of carbon stored in soils.

Another tool is careful forest management.  By growing more forests, growing more trees, and better managing all our forests, we Southerners can seize the advantage of our long growing season to soak up carbon in safe and useful ways.

A modified carbon cycle using biochar for carbon sequestration. Biochar is recalcitrant against decomposition and remains in the soil for centuries or millennia. Thus pyrolysis can transfer 50% of the carbon stored in plant tissue from the active to an inactive carbon pool. The remaining 50% of carbon can be used to produces energy and fuels. This enables carbon negative energy generation if re-growing resources are used. Image credit, Christoph Steiner, 2008.

A third tool is bioenergy systems that also produce biochar. For example, Cool Planet Energy Systems is re-purposing a plant in Alexandria, LA to make cellulosic biofuel while co-producing a charcoal-like soil amendment. The plant will make 10 million gallons per year of biomass-based gasoline from a variety of renewable biomass sources. “The process also generates value through biochar production, which can be returned to the soil, enabling fertilizer and water retention for increased crop productivity, and more robust plant health.”

(Look for an upcoming blog on the recent North American Biochar Symposium.)

These practices that restore soil are sort of a “road less traveled” in climate policy.  For example, in President Obama’s Climate Plan released earlier this year, there was almost zero mention of biocarbon measures – no mention of no-till, composting, cover crops, perennial crops, permaculture, or biochar – but I guess that’s not sexy.

What was mentioned in the plan is better management of forests – recognizing the great need for better management and protection of the forests we already have. However, Obama’s plan focuses solely on Western forests, while there are huge swaths of forests in the Southeast that need similar treatments and policies to lower the risk of runaway wildfires, to strengthen the trees’ resistance to pests and disease, or to offset the pressures to convert to sprawl. Sustainable, residue-sourced biomass energy can help by providing markets for the low-value materials that must be removed to make the remaining trees more healthy.

Even city-dwellers can help pull carbon from the atmosphere: Green roofs, urban gardens, tree planting, backyard composting, etc., are great ways to enrich our lives, improve the places we live, while also storing carbon.

The Earth’s soils hold more than double the carbon of our atmosphere. So how much more might they hold?

“The technical potential of carbon sequestration in world soils may be 2 billion to 3 billion metric tons per year for the next 50 years. Thus, the potential of carbon sequestration in soils and vegetation together is equivalent to a draw down of about 50 parts per million of atmospheric CO2 by 2100.” Dr. Rattan Lal, Ohio State University, 2009.

In short, with broad effort and careful management of biocarbon, we might actually reverse the rise from 350 to 400 ppm.

It is understandable why this subject is frequently overlooked or underestimated. It’s complex: As the authors of the IPCC 4th report noted “There is no universally applicable list of [agricultural] mitigation practices; practices need to be evaluated for individual agricultural systems and settings,”

However, this road less traveled may make all the difference, because these biocarbon approaches deliver multiple value streams:

  • Wise forest management enhances water quality and quantity by strengthening the hydrologic cycle.
  • Sustainable food production reduces water pollution and improves human health with greater nutrient density in food.
  • Soil building practices increase the amount of food we can grow while saving the farmer money on chemical inputs.
  • Growing an energy crop like switch grass on margins around cropland can result in significant soil carbon accumulation, enhanced wildlife habitat, and protection of streams from agricultural runoff.
  • Bioenergy systems that produce fuel, electricity or heat, while co-producing biochar will result in soils having more microbial and mycorrhizal activity (thus more fertility), and greater resistance to drought.

We should consider taking this road less traveled and recognize the massive carbon sequestering potential of soils.  In doing just that, we are launching a Southeast Biocarbon Initiative to highlight and promote these measures in our region.  Stay tuned!

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