The last decade has seen superstorms, forest fires, heat waves, and droughts, to the point where the effects of climate change have been impossible to ignore. And between greenhouse gas emissions, erosion, and crops and livestock in general, farms endlessly and (seemingly) unavoidably contribute to this changing climate. But there are solutions to reduce carbon emissions that farmers could employ. Joseph Romm has written an up-to-date, comprehensive examination of the science behind climate change, what these environmental issues mean for the future, and possible clean energy solutions. Climate Change: What Everyone Needs to Know (Oxford University Press, 2015) is a presentation of how the changing environment will impact nations, families, and you. This quest to decrease global warming might begin on the farm, but, as Romm points out, it ends with the consumer, forcing everyone to step back and consider the morality issues at stake and the health of the world we live in.
The agriculture and livestock sector is a major contributor to greenhouse gas emissions. There are three basic ways that the sector can reduce emissions. First, it can cut its direct emissions of GHGs, including carbon dioxide released from the combustion of fossil fuels. Second, it can alter its practices so as to keep more carbon in the soil. Third, food providers can change what food they produce, because the production of some crops and livestock generate considerably more GHGs than others.
First, like most other sectors of the economy, the agricultural sector can cut CO2 emissions by using more efficient pieces of equipment and by using cleaner energy. Farmers have some options most others do not. For instance, because wind turbines are so tall, farmers have been able to put a large number of them on their land while still being able to farm underneath them. As a result, many farmers have been able to augment their earnings by harvesting the wind. In addition, farmers that raise livestock often have considerable animal waste that emits methane, which can also be harvested and used onsite for power and/or heat generation.
Second, some forms of agricultural land management practices store and preserve more carbon in the soil than others. Modifying tillage practices has been shown in some instances to increase soil carbon storage, but more research needs to be done to identify the optimal strategies and exactly how much carbon could be stored. Similarly, biochar, which is animal and plant matter that has been transformed into charcoal to store carbon in the soil is another option that may be able to remove carbon dioxide from the atmosphere. A 2012 report reviewed the literature on the subject, including 212 peer-reviewed studies. The authors point out that biochar would be an effective carbon reduction strategy only if it were stable in the soil for a long time. Otherwise, it would decompose and release its stored carbon back into the air. Their review “found that the data do not yet exist to accurately estimate biochar stability over time” and so “it is too early to rely on biochar as an effective climate mitigation tool.” The 2014 Intergovernmental Panel on Climate Change report reviewing the literature on mitigation found that biochar might be able to remove substantial CO2 from the air—if there were enough available biomass and if further research and field validation were able to verify high levels of long-term biochar stability in the soil.
The U.S. Congressional Budget Office has identified a variety of other practices that could increase the carbon stored in farmland. For instance, “as farmers rotate which crops they grow on which parts of their land from year to year, they can foster sequestration through frequent use of cover crops—particularly those, like hay, that do not require tillage and that fix carbon in the soil through their extensive root systems.” Other practices that could help store more carbon in farmland include preventing erosion by “planting grasses on the edges of cropland and streams.” Also, grazing management strategies, which includes grazing areas rotation and improved plant species, can help reduce carbon loss on rangeland and pasture.
Third, some crops and livestock produce lower amounts of total GHG emissions per calorie delivered than others. In particular, a December 2014 literature review by the Chatham House, the Royal Institute of International Affairs based in London, points out that “greenhouse gas emissions from the livestock sector are estimated to account for 14.5 percent of the global total.” That means the full life-cycle GHG emissions of meat and dairy are comparable with the direct emissions from the global transport sector. Beef and dairy, which are the most emissions-intensive of livestock products, generate 65 percent of the total GHGs emitted by livestock. Globally, the GHG emissions from producing beef is on average more than a hundred times greater than those of soy products per unit of protein.
Although strategies to reduce those emissions can play a substantial role in reducing their emissions, shifting dietary trends could play a much bigger role. The 2014 IPCC mitigation report has a chapter on “Agriculture, Forestry and Other Land Use.” It concludes that dietary changes are critical to achieving a 2 degrees C target. The IPCC noted that studies have estimated “agricultural non-CO2 emissions (CH4 and N2O) would triple by 2055 to 15.3 GtCO2eq/yr [billion tons of CO2-equivalent a year] if current dietary trends and population growth were to continue.” In terms of reducing that unsustainable increase, the IPCC noted that the “decreased livestock product” scenario would achieve double the emissions reductions that “technical mitigation options on the supply side, such as improved cropland or livestock management” could achieve. The two together could bring future emissions down to 2.5 GtCO2eq/yr.
The IPCC looked at studies that compared business-as-usual GHG emissions in the sector with options that included reduced meat and dairy consumption. They found that “Changed diets resulted in GHG emission savings of 34–64 percent compared to the ‘business-as-usual’ scenario.” Adopting the Harvard Medical School’s “healthy diet” — in which meat, fish, and egg consumption are no more than 90 grams per capita a day — “would reduce global GHG abatement costs to reach a 450 ppm CO2eq concentration target by ~50 percent compared to the reference case.” Of course, the authors quickly add, “Considerable cultural and social barriers against a widespread adoption of dietary changes to low-GHG food may be expected.”
Dietary changes, like all behavior changes, are likely to be some of the slowest type of mitigation strategies to be adopted. Usually a major change in behavior requires a broad societal realization that the behavior is harmful to both the individual and society. In the case of GHG emissions from the food sector, it may simply be the reality of climate change that ultimately drives dietary change. If some of the business-as-usual projections discussed in this book occur, then the world will lose some one third of its most arable land to near-permanent drought and Dust-Bowlification post-2050. At the same time, acidification, along with saltwater infiltration to rich agricultural deltas from sea-level rise, will threaten more sources of food. In addition, this all happens just when we are projected to add another 3 billion people to feed. There is unlikely to be sufficient arable land and fresh water available to sustain all those people on a Western meat-intensive diet. Some combination of rising food prices and government policy and societal pressure to avoid mass starvation could well bring about dietary change.
Finally, it is precisely because the world will likely have to devote so much of its arable land and fresh water to feeding its population post-2050 that it is difficult to see how the agricultural sector will be able to devote significant resources to biofuels. Certainly, our current generation of land- and water-intensive crop-based biofuels are unlikely to be tenable. For there to be substantial bioenergy production after mid-century — other than through agriculture and food waste — would require a commercially viable next-generation biofuel to be developed that can be grown at large scale on nonagricultural land with minimal water input.
Energy conservation is reducing energy consumption through behavior change. Just as dietary change on a large scale could be a very big reducer of greenhouse gas emissions, so could simply changing personal behavior, if it were done on a large scale. Energy conservation could potentially be one of the largest, if not the largest, sources of GHG reductions. However, figuring out how motivated people might be to voluntarily conserve energy in the future is exceedingly difficult, because it requires imagining how people in, say, 2030, will look at their responsibility to the future as it becomes more and more painfully clear that not changing behavior will have catastrophic impacts for billions of people, including their own children and grandchildren.
For the majority of the biggest GHG emitters in the world, especially those in the developed countries, how many of the energy-intensive activities we do every week and every year are truly vital, something we could not live without? How big a house is vital? How much driving is discretionary? How much flying? These are not questions that can easily be answered today.
The physicist Saul Griffith has calculated one of the most comprehensive personal carbon footprints ever done. He did not just examine how much energy is consumed by his commuting and his flying and the appliances in his home, he also calculated in detail the energy needed to manufacture and transport all of the stuff he uses, such as his catamaran, which he uses so much he has to replace it every couple of years. His scientific conclusion is as follows: “A quarter of the energy we use is just in our crap.” How much of our crap can we live without?
As with dietary change, energy conservation is likely to be adopted relatively slowly until there is broad societal realization that carbon pollution is harmful to both the individual and society. However, there are signs that society is beginning to make that realization. For instance, in November 2014, Pope Francis wrote a letter to world leaders saying, “There are constant assaults on the natural environment, the result of unbridled consumerism, and this will have serious consequences for the world economy.” In June 2015, the Pope issued his powerful 195-page Encyclical statement on climate change, which spelled out why it is the transcendent moral issue of our time. As more moral leaders speak out about the potentially catastrophic consequences of our current behaviors, more people may be willing to consider changing them.
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