Climate change and food — what you don’t know about what you eat — Part 2
What factors in the global food system drive climate change? In the last article we identified 3 factors that have driven climate change and land degradation/desertification: population growth, changing consumption habits and climate change itself. In this article, we’ll dig into each of these by understanding the historical context, the current state, and what we can do going forward.
Population Growth
This is easy to understand. More humans mean more resources need to be utilised to feed, bath, cloth, and house them. More cities need to be built, more land needs to be converted into agricultural land, more freshwater needs to be used to create and sustain lifestock and crops.
Before the 1900s, each individual required approximately 1.7ha of agricultural land for their own sustenance. Let’s do the math:
- There are ~100 million square kilometers of habitable (i.e. potentially agriculutral) land
- If the population in 1800 was 1 billion, then they required 17 million square kilometers of land to be dedicated to agriculture.
- Right now, the human population is 7.8 billion people.
- This means, using the same agricultural tools as as the 1900s, we’d need 132 million km2 of land dedicated to agriculture, i.e. more than the total habitable land available to us on our planet
How have we managed to sustain ourselves? Through a multitude of agricultural innovations such as GMOs, fertilisers and pesticides, antibiotics for livestock along with the use of biological tools to increase yield per livestock.
Each of these innovations was necessary to resource the growing human population, and each of these had the effect of squeezing out every last drop of productivity from a unit of land, and livestock animal.
What was the consequence of this? The amount of agricultural land needed per person more than halved in the last 100 years.
What effect has this had on land? Land degradation rates are astonishing. The UN estimates that soil erosion rates are between 10–100 times more than soil reformation rates on agricultural fields. As a consequence, there is more desertification as land becomes unable to sustain life, and so more deforestation to access more arable land. In fact, in 2015, ~500mm people lived in areas that experienced desertification between the 80s and 00s.
Consumption Habits
We mentioned before that 50% of habitable land is used for agriculture, but 77% of this land is used to rear livestock vs. only 23% of land used for crops.
This difference is particularly stark when looking at the difference between the total global calories coming from livestock vs crops. Only 16% of all calories consumed globally come from consuming 77% of agricultural land. Moreover, this difference has been increasing dramatically since 1961.
As the total population increases, land used for agriculture has also increased dramatically. However, with the trends in meat production and consumption, land use for livestock has far outstripped land used for crops in the last 50 years.
Now, although only 16% of calories, and 37% of proteins come from livestock, the segment produces more than half of all emissions that stem from food.
In particular, beef and lamb (i.e. mutton) contribute the biggest portion of emissions from the animal group. Part of the reason behind this is simply how inefficient they are in terms of the land they need, requiring more than quadruple the land that pork needs per gram of protein.
Breaking down the UN’s estimate of 21–37% of anthropogenic emissions coming from the global food system:
- 9–14% come from crop/livestock activities
- 5–14% come from land use (deforestation, degradation, desertification)
- 5–10% come from the supply chain
In total, this accounts for 11.1 GtCO2eq/yr of emissions including land use. Without intervention, the UN estimates this will likely increase by 30–40% by 2050 based on continually changing diets, population growth, and income growth.
Income growth in particular is a very interesting facet. The amount of meat consumption per capita is very strongly correlated to the GDP of a country. The causes of this aren’t straightforward, but the implications are: as we become wealthier, without conscious intervention from each individual, we are likely to continue a destructive trend that over-consumes a finite resource, reducing our ability to fight climate change in the future, and disproportionately contributes to climate change now.
Climate Change: The Land Degradation Feedback Loop from Hell
As a quick aside, I wanted to point out that climate change itself worsens land degradation through natural phenomena such as changing precipitation patterns, heat stress, extreme events (like the Australian bush fires), etc.
As land becomes degraded, it’s potential for agricultural use drops, leading to more emissions and a smaller sink, leading to more climate change.
What’s worse? Higher CO2 levels in the atmosphere increase crop yields (and so put more strain on land) but also decrease the nutritional value per unit. Therefore to provide the same nutrition it may be necessary to increase the number of crops produced, leading to more land degradation, leading to more climate change, leading to less nutritional value and more land degradation, etc.
Food Waste
About 25–30% of all food produced is wasted. The terrible implication of this is is that up to between 5–10% of global emissions comes from food that is not even utilised. Remember that while malnourishment rates are decreasing, there are still an estimated 800 million people suffering from malnourishment now.
Food waste varies by type of food; the biggest contributors by proportion are cereals (30% of supply is wasted), vegetables and fruit (50%), oil seeds, meats and dairy (20%) and fish (35%).
Why does this waste occur? It varies depending on the country and it’s rate of development. In developed countries, the majority of food waste occurs during distribution (food doesn’t reach the consumer in time, or isn’t sold in time), and in the consumers refrigerator or through the consumer simply not consuming all the food they have purchased. In contrast, food waste from developing nations stems mostly from production an retailing.
The UN estimates that reductions in agricultural waste, from more efficient farming methods and supply chain improvements, to more refridgeration and less wasteful behaviour (buying more than you need and throwing away the rest) could save between 1–4.5 GtCO2eq by 2050.
Mitigation
The global food system can essentially be broken down into 2 components: supply side (the agricultural industry) and demand side (us). Effort and innovation are needed from both sides in order to mitigate the impact of this industry on the climate.
The UN estimates that supply chain reductions can reduce between 2.3–9.6 GtCO2eq by 2050 through:
- Soil carbon sequestration (essentially act to decrease land degradation rates below regeneration rates)
- Reduce N2O from fertilizers
- Reduce CH4 from improved manure management techniques, and improved farming practices
- Better grazing systems and more efficient feed for livestock
- Improved harvesting techniques to reduce food waste
The demand side, i.e. us as individuals, can reduce between 1–8 GtCO2eq by 2050 through our own collective actions:
- Improve availability of refrigeration
- Reduce wasteful behaviour
- More efficient diets and mindfullness of what we eat
Next Steps
I will delve into supply chain mitigations in more detail in future articles. For now, the next article will be a detailed analysis of our diet and what we can do improve our impact on the climate.
Diets (and I mean in general our choice of what to eat, not Keto or anything like that) are full of contradictions. I have been stumped for a long time on how to balance eating:
- Food that is healthy but also delicious (delicious and healthy overlap but not entirely, let’s be honest)
- Food that is consistent with my ethical values but also full-fills my nutritional wants and needs
- Practices and behaviours around food that minimize waste but without requiring too much deviation or thought from my day to day activities.
If you’re interested — stay tuned! This will be coming shortly.
