Excerpt: "We think of climate change as a consequence of burning fossil
fuels. But a third of the carbon in the atmosphere today used to be in the
soil, and modern farming is largely to blame."
The Round Barn Farm, Waitsfield, VT. (photo: Mad River Valley)
A Secret Weapon to Fight Climate Change: Dirt
By Michael Pollan and Debbie Barker, The Washington Post
17 December 15
When Will Allen is asked to name the most beautiful part of his Vermont
farm, he doesn't talk about the verdant, rolling hills or easy access to the
Connecticut River. Though the space is a picturesque postcard of the
agrarian idyll, Allen points down, to the dirt. "This precious resource not
only grows food," he says, "but is one of the best methods we have for
sequestering carbon."
We think of climate change as a consequence of burning fossil fuels. But a
third of the carbon in the atmosphere today used to be in the soil, and
modern farming is largely to blame. Practices such as the overuse of
chemicals, excessive tilling and the use of heavy machinery disturb the
soil's organic matter, exposing carbon molecules to the air, where they
combine with oxygen to create carbon dioxide. Put another way: Human
activity has turned the living and fertile carbon system in our dirt into a
toxic atmospheric gas.
It's possible to halt and even reverse this process through better
agricultural policies and practices. Unfortunately, the world leaders who
gathered in Paris this past week have paid little attention to the critical
links between climate change and agriculture. That's a huge mistake and a
missed opportunity. Our unsustainable farming methods are a central
contributor to greenhouse gas emissions. Climate change, quite simply,
cannot be halted without fixing agriculture.
The industrialization of farming has allowed farmers to grow more crops more
quickly. But modern techniques have also wreaked havoc on the earth, water
and atmosphere. Intense plowing, for example, has introduced more oxygen
into the soil, boosting the microbes that convert organic matter into carbon
dioxide. The quest to wring every last dollar out of fields has put pressure
on farmers to rely on chemical fertilizers. This often leaves fields more
bare between growing seasons, allowing carbon to escape into the air.
Scientists estimate that cultivated soil has lost 50 to 70 percent of its
carbon, speeding up climate change.
That loss has significantly degraded soil health, reducing our ability to
grow food. Median crop yields are likely to decline by about 2 percent per
decade through 2100, according to the U.N. Intergovernmental Panel on
Climate Change. At the same time, the world's population is projected to
jump from 7 billion to 9 billion by 2050.
Water availability is also at risk. Currently, 1.6 billion people live in
regions facing severe water scarcity; that number is expected to rise to 2.8
billion by 2025. Agriculture accounts for a whopping 70 percent of all water
consumption. That's in large part because degraded soil doesn't absorb water
efficiently. Instead, water sits on top of the ground and runs off (along
with farm chemicals) into nearby waterways, creating toxic nitrogen "dead
zones."
Remarkably, though, restoring carbon to the soil is not nearly as
complicated as rethinking our transportation systems or replacing coal with
renewable energy. Innovative farmers such as Allen already know the recipe.
He and his team place "cover crops" in their fields, planting things like
oats, rye and beans between rows of vegetables. This practice keeps carbon,
nitrogen and other organic nutrients in the soil. "Keeping as much ground
covered with plants as long as possible allows photosynthesis to draw down
atmospheric carbon into soils," Allen says. A bare field, in contrast,
represents a waste of photosynthetic potential. Allen also composts, limits
plowing and avoids synthetic chemicals like nitrogen fertilizers. In
combination, these efforts have increased soil organic matter by 3 to 4
percent in just three years. Allen also sells some of his cover crops,
adding farm income.
Allen's results are not unusual. Studies have shown that cover cropping,
crop rotation and no-till farming could restore global soil health while
significantly decreasing farms' carbon footprint. Some scientists project
that 75 to 100 parts per million of CO2 could be drawn out of the atmosphere
over the next century if existing farms, pastures and forestry systems were
managed to maximize carbon sequestration. That's significant when you
consider that CO2 levels passed 400 ppm this spring. Scientists agree that
the safe level of carbon dioxide in the atmosphere is 350 ppm.
Regenerative farming would also increase the fertility of the land, making
it more productive and better able to absorb and hold water, a critical
function especially in times of climate-related floods and droughts.
Carbon-rich fields require less synthetic nitrogen fertilizer and generate
more productive crops, cutting farmer expenses.
So why aren't we instituting policies to encourage this kind of "carbon
farming"? For one thing, the science is new and not yet widely disseminated.
Additionally, most of the incentives built into America's agricultural
policies are based on maximizing yield, often at the expense of soil health.
Current federal policy, for example, limits the growing season for cover
crops on the theory that they waste farmers' time and resources on products
that can't be sold. Thus, farmers are denied full crop insurance, price
supports and subsidies if they grow cover crops beyond a specified period of
time. But viewing cover crops as a benefit instead of an impediment to cash
crops would be the kind of climate-smart policy we need. And, as farmers
such as Allen have learned, some cover crops can also be commercialized.
Giving farmers incentives to switch from synthetic nitrogen fertilizers to
organic fertilizers could also lead to healthier soil. Scientists at the
University of California at Berkeley working with Marin County ranchers have
found that applying a single layer of compost, less than an inch thick, to
rangelands stimulates a burst of microbial and plant growth that sequesters
dramatic amounts of carbon in the soil - more than 1.5 tons per acre. And
research has shown that this happens not just once, but year after year.
This is a win-win strategy, both for the climate and the food system, since
the additional carbon in the soil means more grass for cattle and more
profit for ranchers. If the practice were replicated on half the rangeland
area of California, it would sequester enough carbon to offset 42 million
metric tons of CO2 emissions.
The possibilities are endless. What if our farmers received federal
subsidies not just for bushels per acre, but for carbon sequestered or acres
of cover crops planted? Many such changes could be made tomorrow at the
agency level; they would not require congressional action. Incentives for
carbon farming could also bridge the political chasm between ranchers,
farmers and environmentalists. Even those farmers and ranchers who don't
believe in climate change desire healthy soil, high productivity and lush
grasslands. There is a rich opportunity here to completely realign the
politics of agricultural and environmental policy.
America is not there quite yet, but other countries are pointing the way.
This year, the French government launched the 4 Per 1000 initiative, the
first international effort to restore carbon to the soil. Under the
proposal, nations would commit to increasing the carbon in their cultivated
lands by 0.4 percent per year. The French calculate that this would halt the
annual increase in carbon dioxide emissions. Some emerging soil science
estimates that we could store 50 to 75 percent of current global carbon
emissions in the soil.
In the United States, when the Dust Bowl crisis of the 1930s literally blew
soil across the country, our government responded by implementing
agriculture policies to ameliorate the problem. With the stakes even higher
today, our politicians can once again enact policies to reward practices
that rebuild soil carbon.
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The Round Barn Farm, Waitsfield, VT. (photo: Mad River Valley)
https://www.washingtonpost.com/opinions/2015/12/04/fe22879e-990b-11e5-8917-6
53b65c809eb_story.htmlhttps://www.washingtonpost.com/opinions/2015/12/04/fe2
2879e-990b-11e5-8917-653b65c809eb_story.html
A Secret Weapon to Fight Climate Change: Dirt
By Michael Pollan and Debbie Barker, The Washington Post
17 December 15
hen Will Allen is asked to name the most beautiful part of his Vermont
farm, he doesn't talk about the verdant, rolling hills or easy access to the
Connecticut River. Though the space is a picturesque postcard of the
agrarian idyll, Allen points down, to the dirt. "This precious resource not
only grows food," he says, "but is one of the best methods we have for
sequestering carbon."
We think of climate change as a consequence of burning fossil fuels. But a
third of the carbon in the atmosphere today used to be in the soil, and
modern farming is largely to blame. Practices such as the overuse of
chemicals, excessive tilling and the use of heavy machinery disturb the
soil's organic matter, exposing carbon molecules to the air, where they
combine with oxygen to create carbon dioxide. Put another way: Human
activity has turned the living and fertile carbon system in our dirt into a
toxic atmospheric gas.
It's possible to halt and even reverse this process through better
agricultural policies and practices. Unfortunately, the world leaders who
gathered in Paris this past week have paid little attention to the critical
links between climate change and agriculture. That's a huge mistake and a
missed opportunity. Our unsustainable farming methods are a central
contributor to greenhouse gas emissions. Climate change, quite simply,
cannot be halted without fixing agriculture.
The industrialization of farming has allowed farmers to grow more crops more
quickly. But modern techniques have also wreaked havoc on the earth, water
and atmosphere. Intense plowing, for example, has introduced more oxygen
into the soil, boosting the microbes that convert organic matter into carbon
dioxide. The quest to wring every last dollar out of fields has put pressure
on farmers to rely on chemical fertilizers. This often leaves fields more
bare between growing seasons, allowing carbon to escape into the air.
Scientists estimate that cultivated soil has lost 50 to 70 percent of its
carbon, speeding up climate change.
That loss has significantly degraded soil health, reducing our ability to
grow food. Median crop yields are likely to decline by about 2 percent per
decade through 2100, according to the U.N. Intergovernmental Panel on
Climate Change. At the same time, the world's population is projected to
jump from 7 billion to 9 billion by 2050.
Water availability is also at risk. Currently, 1.6 billion people live in
regions facing severe water scarcity; that number is expected to rise to 2.8
billion by 2025. Agriculture accounts for a whopping 70 percent of all water
consumption. That's in large part because degraded soil doesn't absorb water
efficiently. Instead, water sits on top of the ground and runs off (along
with farm chemicals) into nearby waterways, creating toxic nitrogen "dead
zones."
Remarkably, though, restoring carbon to the soil is not nearly as
complicated as rethinking our transportation systems or replacing coal with
renewable energy. Innovative farmers such as Allen already know the recipe.
He and his team place "cover crops" in their fields, planting things like
oats, rye and beans between rows of vegetables. This practice keeps carbon,
nitrogen and other organic nutrients in the soil. "Keeping as much ground
covered with plants as long as possible allows photosynthesis to draw down
atmospheric carbon into soils," Allen says. A bare field, in contrast,
represents a waste of photosynthetic potential. Allen also composts, limits
plowing and avoids synthetic chemicals like nitrogen fertilizers. In
combination, these efforts have increased soil organic matter by 3 to 4
percent in just three years. Allen also sells some of his cover crops,
adding farm income.
Allen's results are not unusual. Studies have shown that cover cropping,
crop rotation and no-till farming could restore global soil health while
significantly decreasing farms' carbon footprint. Some scientists project
that 75 to 100 parts per million of CO2 could be drawn out of the atmosphere
over the next century if existing farms, pastures and forestry systems were
managed to maximize carbon sequestration. That's significant when you
consider that CO2 levels passed 400 ppm this spring. Scientists agree that
the safe level of carbon dioxide in the atmosphere is 350 ppm.
Regenerative farming would also increase the fertility of the land, making
it more productive and better able to absorb and hold water, a critical
function especially in times of climate-related floods and droughts.
Carbon-rich fields require less synthetic nitrogen fertilizer and generate
more productive crops, cutting farmer expenses.
So why aren't we instituting policies to encourage this kind of "carbon
farming"? For one thing, the science is new and not yet widely disseminated.
Additionally, most of the incentives built into America's agricultural
policies are based on maximizing yield, often at the expense of soil health.
Current federal policy, for example, limits the growing season for cover
crops on the theory that they waste farmers' time and resources on products
that can't be sold. Thus, farmers are denied full crop insurance, price
supports and subsidies if they grow cover crops beyond a specified period of
time. But viewing cover crops as a benefit instead of an impediment to cash
crops would be the kind of climate-smart policy we need. And, as farmers
such as Allen have learned, some cover crops can also be commercialized.
Giving farmers incentives to switch from synthetic nitrogen fertilizers to
organic fertilizers could also lead to healthier soil. Scientists at the
University of California at Berkeley working with Marin County ranchers have
found that applying a single layer of compost, less than an inch thick, to
rangelands stimulates a burst of microbial and plant growth that sequesters
dramatic amounts of carbon in the soil - more than 1.5 tons per acre. And
research has shown that this happens not just once, but year after year.
This is a win-win strategy, both for the climate and the food system, since
the additional carbon in the soil means more grass for cattle and more
profit for ranchers. If the practice were replicated on half the rangeland
area of California, it would sequester enough carbon to offset 42 million
metric tons of CO2 emissions.
The possibilities are endless. What if our farmers received federal
subsidies not just for bushels per acre, but for carbon sequestered or acres
of cover crops planted? Many such changes could be made tomorrow at the
agency level; they would not require congressional action. Incentives for
carbon farming could also bridge the political chasm between ranchers,
farmers and environmentalists. Even those farmers and ranchers who don't
believe in climate change desire healthy soil, high productivity and lush
grasslands. There is a rich opportunity here to completely realign the
politics of agricultural and environmental policy.
America is not there quite yet, but other countries are pointing the way.
This year, the French government launched the 4 Per 1000 initiative, the
first international effort to restore carbon to the soil. Under the
proposal, nations would commit to increasing the carbon in their cultivated
lands by 0.4 percent per year. The French calculate that this would halt the
annual increase in carbon dioxide emissions. Some emerging soil science
estimates that we could store 50 to 75 percent of current global carbon
emissions in the soil.
In the United States, when the Dust Bowl crisis of the 1930s literally blew
soil across the country, our government responded by implementing
agriculture policies to ameliorate the problem. With the stakes even higher
today, our politicians can once again enact policies to reward practices
that rebuild soil carbon.
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http://e-max.it/posizionamento-siti-web/socialize
