A Carbon Sweet Spot on Twitchell Island

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by Adobestock/Naj

Grass, Soil, Hope: A Journey Through Carbon Country (Chelsea Green Publishing, 2014) addresses a crucial question: What can we do about the seemingly intractable challenges confronting all of humanity today?  Build topsoil. Fix creeks. Eat meat from pasture-raised animals. Soil scientists maintain that a mere 2 percent increase in the carbon content of the planet’s soils could offset 100 percent of all greenhouse gas emissions going into the atmosphere. But how could this be accomplished? What would it cost? Is it even possible? Author Courtney White says it is not only possible, but essential for the long-term health and sustainability of our environment and our economy.

For a minute, I thought I had stepped into that scene from Lawrence of Arabia where Peter O’Toole, approaching the Suez Canal on foot, sees a ship sailing across the sand.

I had parked on an earthen levee at the eastern end of Twitchell Island, in the great Sacramento-San Joaquin River Delta, east of San Francisco. In front of me was prime farmland, and in the distance, just beyond a slight rise, I saw a big cargo tanker plowing its way slowly across a field à la Lawrence — plowing the middle of the San Joaquin River, of course.

I didn’t drive to Twitchell Island to see farmland, however. I wanted to see a carbon sweet spot in action. Sweet spots are where big things happen in small places for a minimum amount of effort and cost. On Twitchell, a whole suite of big things had happened on just 14 acres of wetland in only a few years. Thanks to a high density of plant matter and a low rate of decomposition, wetlands are the world’s best ecosystems for capturing and storing the carbon from CO2 in their soils. Their destruction, conversely, releases lots of CO2 into the atmosphere as these soils dry out and oxidize. Moreover, at least one-third of the world’s wetlands are composed of peat, a type of soil created by dead or dying plants that are permanently water-bound. Peatlands, which include bogs and fens, contain 30 percent of global terrestrial carbon but cover only 3 percent of the earth’s land surface (8 percent in the United States) — which is a lot of carbon bang for the buck.

Alas, of the approximately 200 million acres of wetlands that existed in the United States during the 1600s, more than half have been destroyed, mostly by draining and conversion to farmland or commercial and residential development. Although the rate of destruction has slowed considerably in recent years thanks to our understanding of the critical role wetlands play in ecosystem health, roughly 60,000 acres are still being lost annually.

  • Published on May 12, 2016
Tagged with: carbon, Carbon in soil, wetlands
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