Saturday, May 25, 2013

The Importance of Restoring Global Soil Carbon

(Global restoration of soil carbon is essential to reducing C02 parts per million in the atmosphere.)

Let's talk about first, why reducing greenhouse emissions to 0 today, isn't near enough to stop drastic climate change. This past month, research studies revealed we have surpassed 400 parts per million of C02 in the atmosphere. This is primarily due to human activity since the industrialization of our societies. If we were to completely stop all fossil fuel burning today, and be completely dependent on clean renewable energy sources, as nice as that sounds, we haven't dug ourselves out of the hole yet. While we bicker today over slowing the rise of parts per million, the reality is we must reduce the parts per million that are already in the atmosphere to effectively mitigate the effects climate change. To do that, we must sequester much more than we are emitting. So how do we go about sequestering, as we also reduce our emissions? View the biomes that we can restore in comparison of how much carbon they sequester on average, then reflect on what biomes are native to your region.

(In Eastern and Midwestern America Temperate Grasslands are carbon hoarders.)

Vegetation and soil ecosystems currently have over 2 trillion tons of carbon sequestered. This is more than 350 times the annual global green house gas emissions. But compared to historic conditions, soil carbon levels in most agricultural fields and many other human altered landscapes types are now reduced by 60 to 90 percent in reference to soil carbon remaining.

In Eastern and Midwestern American the dominant biome is Temperate Forest because of our ample to moderately high rainfall. Wetlands sequester the most. Preservation and restoration where they historically were is their best approach. This is because they only made up .5% of Ohio's original land and pose unique challenges with recreating where they weren't naturally. Grasslands survive where local or regional conditions have rainfalls that aren't adequate for trees to dominate. That doesn't mean that Grassland ecoystems, which once covered much of East in a hotter a drier time period, aren't maintainable within higher rainfall regions. It's a matter of installation techniques, maintenance, and design which truly  requires people in the know. In my opinion restoring native temperate grasslands within Midwestern and Eastern America when referring to specifically carbon sequestration, would be at this point more sustainable than the temperate reforestation and this is why....

Not only do temperate grasslands sequester more carbon on average than temperate forests (see above chart), I argue that because the majority of the carbon is stored in the soil, and not in above ground wood like that of a forest, it's much less susceptible to being re-released unless plowed. Thousand Canker Disease is wiping out the Walnuts (Juglans sp.) coming from the west, the Emerald Ash Borer is killing the Ashes (Fraxinus sp.), the Wooly Adelgid eradicating Spruce (Picea sp.) and Hemlock (Tsuga canadensis), Sudden Oak Death-Oak Wilt- and Gypsy Moths threatens the Oaks (Quercus sp.) and the Asian Long Horned Beetle has the potential to destroy many other species as a generalist pest. Don't forget the American Chestnut (Castanea dentata) and Elms (Ulmus sp.) have already been decimated and Beech (Fagus Sp.) Bark Disease is currently spreading in the Northeast.  What dominant American Temperate trees are currently safe, Hickory (Carya sp.)? And what's to say down the line foreign insects and pathogens don't threaten Hickories also?

Not to say the Eastern and Midwestern forest isn't worth reforesting, rather, in the conversation of sequestering the most carbon, with the most sustainable, and economically recoverable ecosystem, we need to consider the amazing abilities and resilience of American Grasslands.

(An American Tall Grass Prairie reaches it's carbon equilibrium between 20-100 Years)

When looking at a reforestation project, depending on the density of the initial planting and the maintenance, you can expect a closed canopy by as little as 10-30 years. But it won't reach a comparable level of carbon sequestration to a temperate prairie or grassland (same thing), until perhaps 70-100 years. Forest ecosystems store a significant majority of their carbon above ground in the form of wood and annual or evergreen foliage. Grasslands store the majority of their carbon in the soil through the annual break down of extensive root systems that reach 3'-9' feet into the soil depending on the site and plant. Literature states that temperate grasslands sequester soil carbon in a non-linear pattern and finally reach their equilibrium of soil carbon stabilization within 20-100 years. Let's say "carbon maturity" means that the biome has reached its maximum carbon sequestering capacity. Then what the this reveals is that grasslands mature in reference to sequestration, much faster than forests. Given the quicker "carbon maturity" timeline, the greater carbon sequestering ability, the resilience to drought, fire, and flooding, the resistance to foreign insects and pathogens, and the protection of the carbon once sequestered (underground), it has become obvious to me that temperate grasslands deserve a front row seat in the quest of carbon sequestration.

(The Earth Partners estimate that there are over 100 million acres of degraded land in U.S.)

Where do we start restoring our soil carbon? Agricultural lands are a huge source of green house gas emissions from the unsustainable management practices of modern farming we've adopted.  It has been estimated that there are 2.2 billion hectares (1 Hectare = 2.471 acres) of degraded agricultural lands acting as GHG emissions sources where soil carbon restoration could alleviate emissions and increase sequestration. Even then, there are an estimated 5 billion hectares of "under managed" or "improperly managed" grazing lands, grasslands, savannahs, and agricultural lands worldwide that can benefit from the soil methodology Earth Partners has developed. With every 1% increase in soil organic matter on that 5 billion hectares worldwide, we remove 64 parts per million of C02 out of circulation. Soil carbon is the elemental carbon contained within soil organic matter. Right now we are at 400 parts per million of C02 in the atmosphere, let's say we are heading 550 parts per million before we reach a point in time in which we've stopped raising the parts per million. To get from 550ppm back to 280ppm (pre-industrial levels), 270ppm must be removed. So globally a 4.2% increase in soil organic matter on those 5 billion hectares, would potentially reverse the expected situation. We know now that degraded, mismanaged, marginal agricultural lands are an excellent candidate for soil carbon sequestration, but how else can we....save the world?

(The Lawn Institute states that there are 46.5 million acres of lawn in America, 20-25 residential)

In a previous blog post I tried my hand at some improvised calculations using listed sources to estimate the carbon foot print of an acre of lawn. I factored mowing emissions, irrigation, fertilizer, and the sequestering abilities of turfgrass. The results were that the way we maintain our lawns in America, the net carbon footprint is around 6,000 pounds of C02 per acre, per year, conservatively. With 20-25 million located in the commercial and industrial sectors, that presumably do not utilize their large lots of lawn as much as the residential is used, we have an opportunity to sequester soil carbon while cutting emissions close to home. As I stated in the blog post, 5% of U.S. annual carbon emissions come just from lawn equipment. That's apart from the fact that we use potable water to irrigate, pumped into our house which has a large carbon footprint also. We potentially cut annual carbon emissions by well over 5% with the elimination of lawn, but lawn has valuable foot traffic resistant green space qualities for recreation within our metropolitans. So instead let's focus on the residential properties with homeowners that do not utilize their lawns and would like less, large lot owners with excess lawn, and the commercial/industrial lots that include schools, churches, and corporations.

The opportunity to restore different types of grasslands (depending on your region) to increase soil carbon sequestration while cutting into that large carbon foot print of lawn within our own neighborhood, is now. These type of restoration projects will reduce maintenance, save land owners mowing/irrigation costs/time, and strengthen local ecology when properly implemented along with the aforementioned sequestration benefits. When the design is well balanced with the prairie wildflowers, the aesthetic benefits and ecological benefits are also numerous. But even 100% grass prairies without wildflowers offer airy, wind animated textures that climax with excellent displays of fall color and winter structure. This post isn't about local agriculture/permaculture, but I'd like to acknowledge that our 20-25 million acres of residential lawn could also play an environmentally friendly role in localizing food sources when using sustainable practices.

Future carbon tax credits, and taxes along with the current cost reducing design of grassland restoration in lawn areas also make this an attractive economic prospect. Look what this church in Tennessee did to save money, and consequently the environment by installing acres of tall grass prairie in replacement of lawn.




(The science and techniques of creating a stable prairie/grassland community must be respected.)

Whether you're an school district looking to cut mowing costs, a farmer taking advantage of land preservation grants, or interested homeowner with an infatuation for butterflies, the principles and techniques of establishment and maintenance are paramount. Avoid landscaping companies as they will use seed mixes that often don't use all native species or have to many annuals that will yield to perennial weeds. Seek out a local specialist (shameless self promotion insert), or local company that specializes in prairie restoration and/or habitat restoration. If you'd like to try it yourself, I will list multiple educational sources that will start you on your way. But beware! Improper seedling identification, wrong seeding rates, and under or over management within the 1st 2 seasons can and will lead to a dysfunctional weedy mixed community of plants. Flawed installation and design may lead to lessened soil carbon sequestration, degraded aesthetics, and promote noxious weeds.

The focus of this blog post was to bring together my research on the published literature about soil carbon and its' climate change mitigation potential. Along with showing how environmental professionals, commercial/industrial land owners, and/or homeowners can do their part in reducing our parts per million of C02 in the atmosphere. Now I'd like end this post with a youtube video giving some more visual definition of prairies, followed by some additional resources and lastly an easy to understand soil carbon lecture video.




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17 comments:

  1. Soloman you will find this research interesting
    http://www.ofa.org.au/papers/JONES-Carbon-that-counts-20Mar11.pdf

    Cheers
    Mike Parish

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    1. Thanks for this pdf Mike, I will add it to my database of research papers for later reference.

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  2. You are ahead of the curve with this article, Solomon.

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    1. I hope so, I've got your fellow soil scientists, and climate scientists to thank for their publicly published research.

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  3. The soil component is so essential. Here in DC/Maryland, I see some areas that have been preserved...essentially temperate forest such as Rock Creek Park in DC and into the suburbs but the soil is so compacted from high traffic that it cannot do what it needs to do. The trees are tenuous b/c of having no undergrowth to hold the soil. Of course there are deer as well which cause a lot of denuding of anything understory. I heard a reference to 'bare soil being considered a pollutant' and it seems a good starting point for understanding both the value of forest and of meadows. Do you know if 'wetland' would include the riverbanks/creek banks?

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    1. Yes bare soil is a source of both sedimentation in waterways, and much of the time a source of carbon emissions because of the previously sequestered organic matter in the soil no longer being protected or recycled by plants and other organisms.

      Wetlands wouldn't include river/creek banks. The wetland ecosystems holds so much carbon because the high soil moisture doesn't allow organic matter to decompose quickly, so the soil carbon stabilizes at a much higher quantity of organic matter than all other soils. The reason the boreal forest holds so much is similar, there the soil temperature is so cold it restricts decomposition of organic matter so the quantity in the soil stabilizes at a high quantity also. River/creek banks should have some type of riparian forest or similar community around them in Eastern/midwestern and northeastern Usa.

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  4. Solomon, I'm writing a book on this exact topic. Would love to talk to you.

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    1. My email address is Carboncontrolfreak@gmail.com Kristin, I'd be happy to speak with you sometime.

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    2. Kristin, I did work in this area that I shared with Solomon some time back. http://etd.ohiolink.edu/view.cgi?acc_num=osu1187117113. Thanks for informing me about this blog Solomon.

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    3. Solomon, did you get my email? Would love to talk to you this week!

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    4. Mamta, I'd like to talk to you, too!

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    5. I emailed you back a while ago, It must not have sent.

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    6. Just emailed you again.
      If that doesn't work, I'm at kristin.ohlson@gmail.com

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  5. Thanks for the great blog post. I'm looking forward to your work on my landscape, wrightboulter dot com/site.

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    1. Everything's right on schedule for you, this has been a great spring for site preparation.

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  6. You are brilliant my friend! So well researched and presented, leading us to logical conclusions. Way past time to celebrate the prairie! (Also native to Florida I might add)Thank you!

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    1. Thank you for reading! I appreciate the kind remarks, these take a lot of time to write.

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