Summer 2008 Climate Alert
Climate Change & Food Security [ PDF ]
In this Newsletter:
Reducing Our Food's Impact on Climate Change
On the global scale, food production,
the fundamental activity of civilization,
is obviously a massive undertaking. It is
no wonder that these processes account
for over 30% of greenhouse gas emissions.
As we have now recognized the
deleterious effects of global warming
and endeavor to reduce, or mitigate, the
emissions fueling it, the food production
system must come under close scrutiny.
This section will provide an overview
of the situation and introduce a series of
articles to further elucidate some of the
specific complexities of the problem, as
well as efforts now being undertaken in
order to dull the impact that food production
has on climate change.
Contributors to Climate Change
Our food production system produces sizable emissions of three primary greenhouse gasses: carbon dioxide, methane, and nitrous oxide. Specific activities related to growing, raising, or harvesting food that have particularly large impacts on global warming include enteric fermentation, manure, fertilizers, deforestation & soil disruption, and fuel consumption. Fortunately, there are solutions to move forward and reduce our food's impact on climate change.
- Enteric Fermentation to top
In the process of digesting plant matter, bacteria in the guts of ruminants produce and emit large amounts of methane gas. Some amount of mitigation may be achieved by modifying the diet fed to these livestock or by using medical science to alter the bacterial content of their digestive tract. However, the only realistic way to substantially mitigate these emissions is to cut our demand for meat. The article, “Moving Down the Food Chain” explores this issue in greater detail.
- Manure to top
Livestock also produce manure which emits greenhouse gasses as it decomposes. If the waste is allowed to degrade in the open air, such as in a pasture, aerobic bacteria will dominate the digestion and produce nitrous oxide in the process. In instances where the animal waste is instead pooled or submerged, as it is at feedlots or in rice paddies, the oxygen available to bacteria is limited. Here anaerobic bacteria break down the material in a process that produces methane emissions.
With the right infrastructure, the methane emitted from the anaerobic decomposition of manure can be captured and used as a fuel. In cases where methane capture is not carried out, aerobic decomposition is generally seen as having a smaller greenhouse warming impact than anaerobic digestion of manure.
- Fertilizers to top
Artificial fertilizers are used in massive quantities throughout our modern global agriculture system. Many of these chemicals are manufactured from natural gas in a process that produces nitrous oxide. These emissions can best be mitigated by using less chemical fertilizer overall. One way this is being achieved is through the use of better technology and agricultural science that allow for more precise application of these chemicals. Another approach is seen in organic farming, which eschews industrial fertilizers entirely. This process, however, is not without its own problems, for some techniques of organic fertilization of rice can lead to high levels of nitrous oxide and methane emissions. To learn more about how one country is coping with this dilemma, read “Thailand Case Study."
- Deforestation & Soil Disruption to top
Throughout the world, forests (which act as carbon sinks by absorbing atmospheric CO2 in the process of producing biomass) are being cleared, and often burnt, in order to make room for cropland and pastures. In this process, much the carbon content of these habitats, which may have accumulated over hundreds of years, is deposited into the atmosphere in a matter of hours or days. It is important to note that in some areas, the soil itself, not just the living biomass above ground, contains a high level of sequestered greenhouse gasses that can be released into the environment if disrupted.
The most important way to mitigate
greenhouse emissions from deforestation
is to simply stop the process. Doing
so would require that food producers
make better use of the land that is already
devoted to agriculture. According to
this thinking, wasteful practices such as
growing inefficient biofuel feedstocks
or promoting meat intensive diets must
be limited. Other efforts are being made
to not only help reduce emissions from
soils (by using practices such as no-till
farming) but even boost their capacity
as carbon sinks (by using products like bio-char).
- Fuel consumption to top
Our complex
world-wide food economy burns tremendous
amounts of fuel (and therefore
creates large amounts of emissions)
in the process of transporting requisite
input materials and food products. As our article “Cutting Food Miles” explains, one way to mitigate
these emission is to discourage the
purchase of non-local, out of season, or
heavily processed and packaged foods.
Moving Forward to top
In contrast to other aspects of our
food/climate relationship, the situation
involving efforts to reduce this sector’s
negative contribution to climate
change is rather straightforward and
well-understood. Furthermore, much of
the necessary mitigation can be carried
out with existing, relatively inexpensive
technology. The major hurdles, therefore,
are not so much technical as they
are socioeconomic.
Until now, mitigation practices have not been carried out largely because there has never been an incentive or mandate to go through the extra trouble. The “costs” that these practices would have offset (like having a degraded environment and warming planet) were instead simply externalized. Many people believed that the Earth had a nearly endless capacity to absorb the burden of producing cheap food without limit. The reality of climate change and the specter of even larger environmental collapse are now proving that assumption false. The fact that policy makers throughout the world are now considering the implementation of various schemes to put a price on the emission of greenhouse gases is proof that we now know that it is untenable to simply coast into the future with same attitudes and technologies that worked in the past. However, overcoming both inertia and our sense of entitlement will not be easy. As we move forward, we should be reminded that we can still produce good, nutritious, satisfying food for the world’s population while also mitigating greenhouse gas emissions. That goal is attainable. But we can not do so without making serious commitments to restructuring our economic systems, partaking in large scale collaborative efforts to develop and implement new food technologies, and adjusting our cultural assumptions about the role of food in daily life.
Other Articles in this Newsletter:
Climate Change & Food Security
A Message from the President: Fishes, Loaves and Foresight
The Challenges of Producing Food on a Warming Planet
Focus: Moving Down the Food Chain
Case Study: Agriculture in Thailand
The Biofuel Debate: Food vs. Energy?