Agriculture and livestock: Are they victims or perpetrators of climate change?

Though much of the world is focused on transitioning away from fossil fuels as a way to fight climate change, there are other often overlooked contributors to the conundrum resulting from climate change. Two of them are agriculture and livestock. Sure, they provide us with the food we eat every day. But cumulatively, they are also the second largest contributor to greenhouse gas emissions after fossil fuels.

While the majority of global warming activities give off carbon dioxide, the agricultural sector primarily releases methane, which is a greenhouse gas 28 times as potent as carbon dioxide over a 100-year period. The source is mainly rice that is grown on flooded fields with depleted dissolved oxygen. In the absence of oxygen, organic matter in the soil decomposes and produces methane that escapes into the atmosphere. Rising temperatures would cause rice cultivation to release even more methane.

Another source of methane is ruminants, particularly cows and goats. As part of their digestion cycle, they expel intestinal gases, mostly methane, via belches. Methane can also escape from stored manure and organic waste in landfills. If manure is stored as a liquid or slurry in ponds, tanks or pits, it decomposes anaerobically (in the absence of air) and emits a prodigious amount of methane. However, when handled as a solid or deposited naturally on grassland, manure decomposes aerobically and creates negligible methane emissions. Ruminants, manure and rice cultivation account for almost 25 percent of anthropogenic methane emissions.

One of the methods of reducing methane emissions from rice fields, as suggested by scientists at the World Resources Institute, is to plant rice in a raised bed and flood only the furrows. This method has the potential to cut methane emissions in half.

Controlling methane emissions from ruminants is more difficult than trimming or regulating methane emissions from fossil fuels. A large number of mitigation options—namely, diet manipulation, vaccines, chemical additives and genetic selection—have been proposed. They have different efficiencies in lowering production of intestinal methane.

Methane emissions from manure depend on temperature and storage duration. Results from typical Canadian farms indicate that use of underground manure storage tanks, maintained at lower temperatures, lessens methane emissions. Additionally, farmers found that if they clean the tanks regularly, it took longer for methane-producing organisms to grow back. Consequently, methane emissions decrease substantially.

As for agriculture, according to a report of the United Nations published last year, about 50 percent of the Earth's cultivable land is dedicated to growing crops for humans and roughly 30 percent is used to grow grain for livestock. Given how much land it takes to grow food to feed livestock, a very vocal segment of environmentalists insist that "meat is heat" and encourage consumers to go vegan.

Moreover, in line with the projected population growth, global demand for food is expected to grow by up to 70 percent in the coming decades. This substantial increase in demand would require clearing more space for agriculture and cattle grazing, so that the per capita threshold of land required for a nation to be self-sufficient in food production could be maintained. Vast swaths of the Amazon Rainforest, along with lands and forests in other places, are already being cleared for growing crops and grazing cattle. If current trends continue, most of our planet's remaining land and forests would need to be cleared to feed the world.

Deforestation and land degradation indirectly contribute to the negative impacts of atmospheric carbon dioxide. One of the main reasons for this is because forests are natural carbon sinks. They absorb carbon dioxide from the atmosphere and converts it into oxygen that we breathe in. Hence, by cutting down big areas of forest without replacing the trees that are removed, we are causing an inadvertent change in the amount of carbon dioxide in the atmosphere.

Several studies indicate that planting more than two billion acres of trees could remove two-thirds of all the carbon dioxide that human activity has pumped into the atmosphere since the Industrial Revolution. Trees also recharge the water table and create microclimates that increase local rainfall. In addition, deforestation puts biodiversity at risk, further undermining nature's ability to cope with the impacts of climate, for example absorbing heavy rainfall.

Clearly, agriculture in general, and livestock in particular, contribute considerably to climate change. Nevertheless, climate change is also a major threat to the sustainability of livestock globally. An increase in air temperature as a result of global warming directly affects milk and meat production, reproductive efficiency and health of the animals. Also, excessive heat would reduce their body size and fat thickness.

Agriculture is also highly vulnerable to climate change. It is affecting food security by raising the risks to food supply due to heat waves, drought, flood, storms, soil depletion and desertification. Over the coming dozen years or so, farmers in developing countries, especially in South and Southeast Asia, will be the ones to bear the brunt of global warming, as per a recent report of the Food and Agricultural Organization of the UN.

It could, therefore, be said that agriculture and livestock farming are caught in a vicious cycle that makes them both victims and perpetrators of the harmful effects of climate change. Most of the times when agriculture perpetrates its crimes, it is not even contributing to feeding the ever-increasing world population. Instead, a good portion of the agricultural products are consumed by livestock—mostly bovines—which demonstrates this paradox.

How do we solve this complex problem? The solution obviously requires a coherent and integrated approach to climate change, energy usage and food security. Faced with global warming, competition for scarce resources, and inaction by world leaders, we, the people, have to transform the entire global food system and make it much more resource-efficient while continuously curbing its environmental impacts, including its greenhouse-gas emissions.

We also have to increase yields while curtailing dependence on agrochemicals. Besides, we should minimise food waste, cut down consumption of resource-intensive and greenhouse gas-producing foods, notably meat, and switch to climate-friendly vegetables, such as the nutritionally rich seaweed kelp. Farming kelp is beneficial for the ocean.

Furthermore, employing sustainable practices, like organic agriculture, has enormous potential to help in the fight against global warming, whereas maintaining the status quo with widespread industrial agricultural practices will continue to be terribly detrimental to the climate. In short, making agriculture and livestock industries and all associated activities sustainable is the answer to win the battle against global warming, as well as accelerate the transition to a healthier and more just society.

Quamrul Haider is a Professor of Physics at Fordham University, New York.