Global Warming Spreads Seeds of Change


With sea level rise at our doorstep and storms chomping away at the shoreline it's time to rethink an economy based largely on seasonal, coastal recreation. Why? Because as Ginny Jones, a lifelong Islander from a farming family muses so succinctly, "We can't eat tourists."

What we can eat is local food. Farms provide sustenance to the human Island population. As climate change disrupts the Island's natural environment it will fray the local economy. It will impact farming too, with more heat, rain, storms and drought, but farmers can reshape the way they farm more easily than the rest of us can hold back the sea. Producing more local food, as tenuous as farming can be, especially in light of climate change, may make better economic and social sense than selling beach balls or T-shirts.

The Martha's Vineyard Agricultural Society dates back to 1859. The Martha's Vineyard Commission's 2010 Island Plan notes that "Agriculture has been integral to the Island's culture and economy for generations and has shaped the landscape, though much of the Island's farmland has disappeared over the last century, transformed into subdivisions or allowed to revert to wooded areas."

At the Native Earth Teaching Farm in Chilmark, Rebecca Gilbert says, "We are not raising much of our own food and that makes me nervous. Our food supply is very tenuous."

And climate change won't help. Originally it was thought that increased levels of carbon dioxide would be a boon to agriculture by increasing plant growth. And while it is true that some crops will grow bigger and faster, there are other, negative impacts that may outweigh the positive - rising temperatures, ozone pollution, extreme weather events and increased threats from pests, weeds and crop disease.

Rising temperatures will allow some plants that need a longer growing season to thrive, like melons and sweet potatoes, tomatoes and peppers. But more heat will inhibit the growth of crops suited to cooler conditions including potatoes, lettuce, broccoli and spinach.

Plants that require long winter chills, such as blueberries and cranberries, may no longer be able to grow in Massachusetts. Higher temperatures can increase soil evaporation rates and require more water for plants to keep cool. Heat stress can affect milk production and animals' ability to gain weight and reproduce. More severe summer droughts are expected to reduce crop yields.

At Morning Glory Farm in Edgartown, Jim Athearn says he "worries every time it rains - is this the severe weather? It causes erosion and the leaching of nutrients put into the soil for the crops. The changes do bother me. The rain is not gentle anymore."

Caitlin Jones at Mermaid Farm in Chilmark says every time she goes to a conference farmers throw up their hands about the weather and say: "Who the heck knows anymore?"

Climate change makes farming more difficult, says Ms. Gilbert. "Things bloom earlier and are vulnerable to frost. Spring gets disrupted earlier. It is less and less predictable, and that is not a good thing for agriculture because a lot of it is about guessing what may happen in the next few months, and we're not able to predict very easily."

A report by the U.S Global Change Research Program states: "Extreme events such as heavy downpours and droughts are likely to reduce crop yields because excesses or deficits of water have negative impacts on plant growth ... One consequence of excessive rainfall is delayed spring planting, which jeopardizes profits for farmers paid a premium for early season production of high-value crops such as melon, sweet corn, and tomatoes. Field flooding during the growing season causes crop losses due to low oxygen levels in the soil, increased susceptibility to root diseases ... " The report adds:

"Another impact of heavy downpours is that wet conditions at harvest time result in reduced quality of many crops. Storms with heavy rainfall often are accompanied by wind gusts, and both strong winds and rain can flatten crops, causing significant damage. Vegetable and fruit crops are sensitive to even shortterm, minor stresses, and as such are particularly vulnerable to weather extremes ... "

Pests and disease are no small concern either. According to the same report, "Warming aids insects and diseases in several ways. Rising temperatures allow both insects and pathogens to expand their ranges northward. In addition, rapidly rising winter temperatures allow more insects to survive over the winter, whereas cold winters once controlled their populations. Some of these insects, in addition to directly damaging crops, also carry diseases that harm crops. Crop diseases in general are likely to increase as earlier springs and warmer winters allow proliferation and higher survival rates of disease pathogens and parasites. The longer growing season will allow some insects to produce more generations in a single season, greatly increasing their populations. Finally, plants grown in higher carbon dioxide conditions tend to be less nutritious, so insects must eat more to meet their protein requirements, causing greater destruction to crops."

More pests, weeds, invasives species, and crop diseases put pressure on farmers to use more herbicides and pesticides and at higher concentrations, though less so, perhaps, on small farms.

Ginny Jones explains why small family farms are more environmentally friendly than agribusiness. "Most are probably somewhat, if not totally, diversified; they use lower impact machinery, and appreciate the necessity of preserving biodiversity and habitat for wildlife. They are more likely to use manures and composting as soil amendments instead of trucked in material. In addition, they are more likely to be organic or using best practices if not totally organic. Some may be raising rare breeds which are more hardy or have other special characteristics, and need less medical intervention."

Mr. Athearn notes that "local farmers learn the lore and culture of what it takes to grow crops where they are, be it sub-Saharan Africa, the Rocky Mountains, or the Vineyard." He mentions no-till farming. "It leaves more crop residue, increases soil retention, and does great things for the field."

No-till farming involves planting crops without using a plow to turn the soil. It helps retain soil carbon and preserve soil nutrients. It involves selective herbicide use, herbicides that Mr. Athearn notes "may not be harmful, mayor may not leach anymore." The point, he adds, is that "there is a lot of good technological change. Biocontrols, beneficial insects, we're using them all the time, and they may be able to handle" climate change stress. He adds that if the climate changes slowly over 50 to 75 years farmers will be able to "adapt to accommodate."

Rattan Lal is director of the carbon management and sequestration center at Ohio State University and the lead author of a report on no-till farming. In the journal Science, he wrote: "If every farmer who grows crops in the United States would use no-till and adopt management practices such as crop rotation and planting cover crops, we could sequester about 300 million tons of soil carbon each year." He adds: "No-till is definitely a short-term fix, but it may buy us up to 50 years to find alternatives to fossil fuels."

Other adaptation measures also include changing planting dates, changing to crop varieties with improved tolerance for heat, drought and other weather extremes, as well as those adapted to longer growing seasons.

A report by the Northeast Climate Impacts Assessment notes that, "growers of raspberries and blueberries could potentially adapt to warmer winters by switching to varieties with lower chilling requirements, which were originally developed for production in southern and western states. For long-lived orchard crops such as apples, and varieties with no known substitute such as cranberries, options are currently far more limited."

As a farmer at a teaching farm, Ms. Gilbert feels responsible to "encourage people to grow more food, here and there, in bits, rather than buying it all from foreign countries and California and bigs farms somewhere else. Little home gardens, backyard chickens," she suggests, and "plants trees with edible fruits and nuts - even if not tended every year they still produce food."

A good resource for backyard gardeners is The Climate-Friendly Gardener; A Guide to Combating Global Warming from the Ground Up, by the Union of Concerned Scientists.

Ms. Gilbert says she sees a lot of interest in farming among young people. "Kids see more clearly, young people think toward the future. They need adult confirmation to empower them." Farmers, she adds, are perceived to be "much more cool than they were when I was a kid."

As an island, the Vineyard is a bull's-eye for climate change disruption. Yet as a resort community we are less of a national, economic priority than major cities and more populated regions.

In his book, The Flooded Earth Future in a World Without Ice Caps, author Peter D. Ward writes: "We could witness inundated cities and coastal communities that produce nothing and consume much, and that would put the brakes on their country's GNP. 'Recession' is too fine a word for what would ensue from storm surge alone; major economic depression would be probable."

On the Vineyard we need to plot our economic and environmental future now. Local food production, despite the climate change challenges - but also because of them - should be a priority.

(Sources: Confronting Climate Change in the U.S. Northeast, a report by the Northeast Climate Impacts Assessment; Global Climate Change Impacts on the United States, a report by the U.S. Global Change Research Program; and the U.S. Environmental Protection Agency).

This series of 14 essays about climate change was published in the Vineyard Gazette over a period of seven months in 2011. It appears here with permission. Copyright Vineyard Gazette. All rights reserved.