The Not-So-Visible Climatic Cost of Feeding the World.
How does the food we eat affect the climate?
This is part 1 of a series of posts I plan to write on food and its relationship with the changing climate.
Back in 2015, on the platform that was once called Twitter1, I came across a tweet that mentioned that the food we eat impacts the climate. Reading that made me wonder how something as simple as the food we consume every day for sustenance can affect the climate, an external phenomenon that indicates the long-term weather pattern of a region. For me, food nourishes the soul and is something to be relished and cherished—how can this damage the environment? So, I promptly replied to the tweet posing my question, and the author of the tweet replied with a link to an article in The Guardian that explained (somewhat) the connection between food and climate. I couldn’t quite grasp the entire picture, so I decided to dig deeper on my own. As I researched the topic further, I gradually began to comprehend the complexity of the entire food system.
Over the past few years, I have read numerous articles, books, and listened to many podcasts on this topic. However, I still struggle to explain in simple and understandable terms how the food we eat impacts the climate, especially human-induced climate change. That’s why I decided to write about it, both to deepen my understanding2 and help you, dear reader. Whether you’ve heard about this issue before and find it confusing, or if you’re already an expert, I invite you to read along.
Since the topic is complex, I will break it down into a series of posts, explaining different aspects—from the effects of food on climate to whether changing our diet matters, and clearing some commonly held misconceptions around the topic. Before I start blurting out some facts on how the entire lifecycle of food production impacts the climate, I want to briefly discuss why it is difficult for us humans to wrap our heads around this complicated issue.
Why is it so darn hard to understand?
The human psyche is complex. For hundreds of thousands of years, we were hunter-gatherers, living in a rather less predictable environment, hunting for meat and frequently foraging for plant food. Over these years, our brains evolved to sense immediate and visible dangers in our surroundings and respond to them accordingly.
Only in the last 10,000 years have humans decided to settle down and engage in subsistence farming, which led to the development of agriculture. Consequently, our threats to survival have reduced because food has become more accessible and readily available on our plates. This also resulted in population growth, which, in turn, increased the demand for food. Over the last few hundred years, particularly with the rise of the Industrial Revolution, the demand for food has been soaring, and it has begun to have a significant impact on the climate.
However, on an evolutionary timescale, the agricultural and industrial eras are tiny blips—agriculture has existed for 5% and the Industrial Revolution for 0.1% of our species’ time on this planet3. Evolution is slow and messy, and our brains are still attuned to how we used to react to immediate and tangible threats to our surroundings for most of human history. On the contrary, climate change is gradual, invisible, and abstract, which our minds just cannot comprehend. In evolutionary biology, this is referred to as an evolutionary mismatch.
Evolutionary mismatch refers to the adaptive lag that occurs if the environment that existed when a mechanism evolved changes more rapidly than the time needed for the mechanism to adapt to the change.4
This makes it difficult for people to connect everyday behaviors, like eating habits, to global consequences like changing climate patterns.
Our intuitions are usually different from reality. When asked what behaviors are most effective at reducing their footprint, most people said recycling and eating locally, and underestimate other high-impact choices, such as high-carbon foods (which I will come to shortly). This is intricately tied to the social lens of how an individual in a community considers their eating habits. We cannot deny the fact that food habits are incredibly personal, often attaching them to one's identity and cultural beliefs.
Food production is highly complex, involving indirect variables like deforestation, emissions from livestock, and the supply chain. Often, we are unaware of all the processes behind the scenes to bring food to our plates. We just visit a supermarket nearby, buy our food, and rarely consider how it got there. This lack of awareness and transparency increases people's resistance to changing their behavior, thinking it doesn’t affect them imminently. As a result, they tend to delay their actions until far into the future. As George Marshall in his book Don’t Even Think About It puts it,
…. dealing with climate change requires that people accept certain short-term costs and reductions in their living standards in order to mitigate against higher but uncertain losses that are far in the future.
Not to mention, politics plays a pivotal role in shaping people’s beliefs on climate change through group identity and cultural affiliation. Political policies drive systemic changes that could address climate issues in a top-down manner. However, if the political environment is not receptive to the seriousness of the problem, the people may perceive the claims as exaggerated and view the issue with skepticism. People also tend to view these complex issues through a cultural lens rather than scientific facts. Cultural identity and its portrayal in the media can further increase people's prior biases, such as confirmation and availability biases.
These are some of the primary reasons why it is so difficult for our brains to comprehend this behemoth of a topic. Now that we have some sense of how such complex issues play out in our minds, we can perhaps be more curious by asking more questions, learning from them, and being more mindful about our choices, instead of outrightly believing and accepting what we hear.
Why is the climate changing? A brief aside.
Climate change—specifically human-induced climate change—is undoubtedly a part of our lives today. It is primarily caused by the emission of Greenhouse Gases (GHGs), such as carbon dioxide, methane, and nitrous oxide, among others, into the atmosphere. These gases have lopsided molecules where the heat gets trapped in their molecular bonds and then reemitted back into the atmosphere, thus increasing the temperature.
Every natural process in the universe requires energy to sustain itself. The GHGs mentioned above have been part of the planetary ecosystem for millennia, which has sustained itself through natural processes and feedbacks over geological timescales. The Earth’s climate has undergone cycles of warming and cooling, which were gradual and influenced by natural events. Only in the last three centuries, specifically since the advent of the Industrial Revolution, have humans emitted unprecedented levels of GHGs, which have profoundly altered the balance of these natural events, with temperatures rising rapidly at rates not seen for millions of years.
This warming is only a part of the problem when it comes to climate change. Since the climate is composed of various interconnecting systems, the warming can further drive significant changes in sea level, sea ice and glacier balances, rainfall patterns, and affect the biodiversity of our planet.
Although the Industrial Revolution was a significant turning point in the changing climate, the cumulative effects of earlier human activities, especially farming and agriculture, gradually transformed the climate at slower rates. The Industrial Revolution, coupled with technological and scientific progress, considerably accelerated agricultural practices. This food fed more people, leading to a population surge, which in turn meant more people to feed, resulting in the growth of agriculture and farming, and thereby emitting more greenhouse gases5.
How do agricultural practices change the climate?
There are two aspects to the problem of the impact of agricultural practices on our environment: one, the GHG emissions arising from agriculture, and the second is the overall impact of agriculture on the environment, which includes the former, along with land and water usage, and the impact on the biodiversity of wildlife. I will only address the first here6.
Agriculture, which includes animal farming, encompasses food production (both plant and meat products), food processing, and distribution. The GHGs emerge from all these steps, which overall amount to approximately one-fourth of the total global GHG emissions. The chart below sums it all up7.
Let’s start from the bottom of the graph. Land use accounts for almost a quarter of the food emissions. The emissions here mainly come from deforestation and the subsequent use of that land for food production. Forests act as a carbon sink, meaning that the ecosystem within the forest can store carbon both in the trees themselves and in the soil in which they grow. Disrupting this ecosystem leads to the release of carbon that was previously stored. Currently, half of the habitable land8 is used for agriculture, out of which 80% is used to grow food just to feed farm animals and for grazing. Only 20% of the remaining land is used to grow food for human consumption. My mind almost exploded when I saw these numbers. I will return to this point in my subsequent post, as I have a lot to discuss on this topic.
Next is the crop production itself, which involves agricultural practices such as the use of fertilizers and manure, resulting in the release of nitrous oxide, methane emissions from rice cultivation, and carbon dioxide emissions from agricultural machinery.
Livestock emissions account for emissions from raising animals for human consumption. This includes meat, dairy, eggs, and seafood. The grazing animals, mainly raised for meat and dairy, have a specialized compartment in their digestive system called the rumen9, which, with the help of in-house bacteria, helps them break down tough plant materials such as grass and cellulose, making it easier to digest. This process is called enteric fermentation. A by-product of this process is methane, which is a potent GHG10 that these animals burp out, causing the majority of emissions in this category. The remaining emissions originate from the fuel used for trawlers in fishing, as well as in pasture and manure management.
The remaining emissions from food come from the supply chain, which includes food processing, transport, and packaging combined. One of the side effects of an efficient supply chain is food waste that can occur during any of the stages mentioned above. Surprisingly, about one-fourth of the food produced goes wasted. This food waste, when left untreated, can rot and release methane into the atmosphere. This is in addition to the emissions required to produce the wasted food in the first place.
I have attempted to summarize the topic of climate change and its relationship to food production to the best of my ability. Each of the topics discussed could be a blog post on its own, but I tried to spare the technical details and focused more on how food is contributing to the problem. I hope you took something helpful from this post. I’m not done with this topic (yet)—in the subsequent post, I will strive to answer if changing our diets can really make a dent in this mammoth of a problem. Until then!
I still call it Twitter and refuse to call it X; whatever a post on the platform is now called, I still call it a tweet.
What better way to learn than writing about it?
Another useful analogy for some perspective of timescale: if you compress human history down to a 24-hour day, we were hunter-gatherers for 23 hours, 40 minutes (the vast majority of our tenure), started agriculture in the last 20 minutes, and the Industrial Revolution began in the last 35 seconds (about 250 years).
Li, Norman P., Mark Van Vugt, and Stephen M. Colarelli. "The evolutionary mismatch hypothesis: Implications for psychological science." Current Directions in Psychological Science 27.1 (2018): 38-44.
I want to clarify that food is one of the significant sources that affect the climate. Other sectors, such as industry, electricity, and transport, also contribute to climate change, but I will not address them here.
For a deeper understanding of the overall environmental impact of food production, I highly recommend reading this article in Our World in Data.
Hannah Ritchie (2019) - “Food production is responsible for one-quarter of the world’s greenhouse gas emissions” Published online at OurWorldinData.org. Retrieved from: 'https://ourworldindata.org/food-ghg-emissions' [Online Resource]
Habitable land excludes glaciers and barren areas, such as deserts, beaches, and dunes.
Animals that have a rumen are also known as ruminants.
Methane is a short-lived gas, meaning it stays in the atmosphere for a shorter period compared to carbon dioxide. Although it is short-lived, it is more potent as it can trap more heat than carbon dioxide. To give an idea, Methane is 34 times more potent at trapping heat than carbon dioxide over a 100-year time horizon, but it is 86 times as potent over 20 years.
The population of the planet has more than doubled in less than a hundred years. Yet aside from a short period in the 80s, nearly no one is talking about it. Degrowth is a mandatory minimum for human survival for numerous reasons, of which population size is the major factor.