As a farmer and grape grower, the effects of climate change are hard to miss, and the news is getting worse. Even the best-case projections regarding temperature, sea level rise, floods, fire, disease, and agricultural output are frightening. Partly due to changes in the climate, extinction rates among all species are about 1,000 times greater than they would be in the absence of human activity. Pulitzer prize winning author Elizabeth Kolbert has called this phenomenon The Sixth Extinction.
Ecologists and philosophers have started to wonder whether humans will survive the climate change experience, reminding me of a Tom Lehrer tune from the 1960s. Expecting that we will survive, my Christmas wish is that the resulting world will be the kind in which our grandchildren will still want to live.
The immediate cause of changes in the climate is an imbalance between carbon storage in soil and other reservoirs and its release into the atmosphere as carbon dioxide, trapping heat and acidifying the oceans. (You can learn more about the carbon cycle here.) While burning fossil fuels gets most of the attention, modern agriculture, through deforestation, mechanical and chemical disruption of soil, and confined livestock facilities, has contributed as much as 40% of the increase in atmospheric CO2.
It doesn’t have to be this way. Trees, grasses, and other plants carry out photosynthesis that uses the carbon from CO2 to produce sugars that are transported via the roots into the soil, feeding a diverse ecosystem of microbes, insects, earthworms, and even vertebrates. Agricultural approaches may thus be deceptively simple yet practical and potentially powerful methods to extract CO2 from air and store it as organic carbon in the soil. Research suggests that adding 0.4% more organic matter each year to agricultural land across the globe would sequester all the CO2 released by human activity.
Is 0.4% per year additional organic matter achievable? Absolutely. Using cover crops and advanced grazing techniques, North Dakota rancher and farmer Gabe Brown has added organic matter at about twice this rate for 25 years, providing proof of principle. University of California at Berkeley Professor Claire Kremen has done the design work, USDA’s Sustainable Agriculture Research and Education program has done field trials and created educational programs and tools, and organizations such as Future Harvest CASA and county agricultural extension offices offer support, education, and knowledge sharing among farmers and landowners in our region.
Put simply, while building soil organic matter may be only one part of an overall solution to global warming, it is literally “shovel ready.” The challenge now is spreading the word, creating the incentives, and putting on our boots. As we approach the start of the 2019 session of the General Assembly, there are several critical actions to take.
First, we should hold Governor Hogan and the Maryland Department of Agriculture accountable. In 2017, the General Assembly passed the Maryland Healthy Soils Act that requires MDA to provide incentives that would improve soil health, monitor progress, and help the state meet goals set by the Maryland Climate Change Commission. Despite the promise, no new practices or incentives have emerged. To reinvigorate this program and regain climate leadership for the state’s largest industry, Maryland could join California in committing to the Global Soil Health Challenge.
Second, state and county representatives should add a “carbon note” to all legislation. Proposed legislation in Maryland is always accompanied by a “fiscal note,” a brief description of the potential financial consequences of the bill. But fiscal notes don’t include other indirect costs to the taxpayers, such as the cost of global warming. In order to help legislators understand the benefits and risks of legislation on climate change, a similar “carbon note” could be required. The practice would help keep the issue front and center.
Third, we need to modify incentives so that farmers will implement methods that will add carbon to soil. Today’s agricultural methods were developed during the Green Revolution, in the aftermath of the great depression, the dust bowl, and World War II, when energy was cheap and plentiful and people around the world were hungry. Tax policy, agricultural programs, and business practices designed to support these systems now have entrenched interests behind them, making alternatives hard to implement. Difficult as it may be, revising tax policy to account for the climate-related costs of carbon use would accelerate the transition to “carbon farming.”
There are also a few things you can do at home to return carbon to the soil. First, you can let your grass grow. As it grows, the ratio of carbon to nitrogen in the blade increases. In contrast, short cuttings (those that result from weekly lawn mowing) have high levels of nitrogen that, because there is little carbon to hold it, then leaches into ground water and the Bay. Infrequent mowing, annually is best, has other advantages. Less fuel and labor are needed, long roots improve soil structure allowing better water infiltration, and over time a natural meadow of diverse plants, insects, and wildlife will develop.
Second, you can plant an edible landscape on even a small plot of ground. Americans often plant vegetable gardens during times of scarce resources. About 20 million households established victory gardens during World War II, and nearly half of all Americans grew their own vegetables during the early 1980s recession. The personal benefits include reductions in transportation (both from farm to market and market to home), better nutrition, and the sense of community that comes when everyone does their part. There are added benefits of incorporating these herbs and vegetables into the landscape in terms of soil health, reductions in pesticide use, and aesthetics.
Because they sequester twice as much carbon as forestland, vineyards represent an excellent way to add carbon to soil. When we started, average soil carbon was less than 1%, and unmeasurable in some areas. Through cover cropping, reduced soil disturbance, and compost additions, we are up to about 2.5%, about the norm for most vineyards in the world, but we think we should go higher. Although conventional wisdom says that vines should struggle, we believe that additional organic matter will result in healthier, more resilient plants that will resist disease, ripen earlier, and have more flavor. At least this is the experience of some of the best châteaux on the left bank in Bordeaux.
While storing carbon in soil is a simple tool to help solve the current climate challenge, the transition will not be easy. Agriculture is more perspiration than romance, and some of these methods are labor intensive. Farm labor is in short supply, and there will inevitably be a process of trial and error as we determine the right crops and cover crops for our environment and each agricultural product. In the short term, these factors could result in reductions in farm incomes. But long term, reducing CO2 and creating resilient landscapes is the best way to prevent, or at least mitigate, the catastrophes of climate change.And, of course, more carbon in the soil leads to more nutritious, flavorful food and wine, and that will also make our grandchildren’s world a better place to live.