Climate change and food — what you don’t know about what you eat — Part 1
The global food system accounts for between 21–37% of all anthropogenic (human driven) GHG (greenhouse gas) emissions. Let’s dig into why, and what that means for the climate, for humans as a whole, and for us as individuals.
Introduction
In a previous post, we encouraged you to calculate what your carbon footprint looks like. If you haven’t, no matter, but if you have, and you are like me, you came away thinking “Well, that’s informative! But now what?”.
Well the purpose of this article is to take a step down that road. Over the next few articles, we will talk about food. More specifically, the impact our consumption of food has on the climate, and, more insidiously, the effect the climate has on food.
We’ll dive in to understanding the interaction between our diets and the environment better, the relative benefits of different diets, and what we can do to improve both food/water security, and lessen the impact on the climate.
Historical Context
It is a well known fact that the human population has been increasing exponentially. Reaching 1 billion people took us 200,000 years, but reaching our current 7.8 billion took us just over 200. What is less known, is that the calories consumed per capita has also increased dramatically, up an astonishing 33% since just 1961. Since 1961, consumption of meat and vegetable oils has doubled. What does this mean for supply? Production of meat has more than quadrupled in the same time.
Moreover, every UN projection of future human growth, consumption patterns and population change between now and 2050 results in even more increased demand for food, feed and water.
These changes in consumption habits have left 2 billion people overweight, with a steady increase since the 70s. Despite this, 821 million people remain malnourished, although this has dropped nearly 50% since the 70s.
Why does any of this matter? Because the global food system (all the way from farming/livestock rearing, to production, packaging, retailing and consumption) is responsible for approximately 26% (between 21%–37%) of all anthropogenic greenhouse gas emissions.
Moreover, 50% of global habitable land is currently being used for agriculture (with the rest being forests and shrubland), with agriculture accounting for 70% of global fresh water use. This has implications beyond climate change, with major consequences for future food and water security.
How is this possible? Where do these come from? Why does land use matter? Let’s dig in.
Land Use, the AFOLU Sector, and Sustainability
The global food system isn’t itself well defined. Instead, the UN groups all agriculture related activities under the Agriculture, Forestry and Other Land Use (AFOLU) sector, which is responsible for the global supply of food and other land-based raw materials.
Land is the critical resource for the AFOLU sector. It provides food and fuel to our species, and livelihoods for billions among us. Why does use of land matter in climate change? Firstly because the AFOLU sector emits 13% of all anthropogenic CO2 emissions, 44% of methane emissions (from livestock, rice cultivation, etc.) and an astonishing 81% of nitrous oxide (a GHG 298 times more powerful than CO2, from manure storage, agricultural soils, biomass burning, etc.). These emissions are intimately linked to how the AFOLU sector uses the land, which is driven by our demands as consumers.
Land is also a finite resource, and more importantly one whose rate of renewal is much, much slower than our current rate of use. With the changing trends in consumption and towards meat consumption, not only are we rapidly running towards the maximum capacity our land can support, we are also losing habitable land to degradation and desertification pressures, intensified even further by climate change. So not only is land a finite resource, it’s a shrinking resource and climate change increases the rate of shrinkage.
Between 2007 and 2016, the UN estimates that a net of 5.2 GtCO2eq/yr occurred, largely caused by deforestation activity stemming from increased agricultural demand and demand for raw materials, equivalent to ~12.5% of total anthropogenic emissions.
Critically, land is also the second largest sink of greenhouse gases (after oceans). The natural response of land to anthropogenic activity has caused a sink equivalent to 29% of global CO2 emissions, but the persistence of this sink is uncertain due to land degradation and climate change. The degradation of this capacity could have severe implications on the fight on climate change. For example, forests are a critical part of the sink. They are a colossal store of carbon; called the forest carbon stock, forests sequester carbon from the atmosphere and store it within themselves. Deforestation contributes to the release of this stock back into the atmosphere, causing climate change, and afforestation does the opposite, taking carbon from the atmosphere and storing it away.
More than 1/4 of land currently undergoes degradation (the decline in it’s capacity to sustain life). This has serious implications for food security (lessening of arable land), and also emissions (since less land is acting as a sink for greenhouse gas emissions).
This increased stress on land is due to a number of different factors, including:
- Population growth
- Changes in consumption habits to favour more land intensive commodities (like meat)
- Climate Change
Response Options
We will delve deeper into potential mitigations in the second part of this article. However, the UN produced a very comprehensive and digestible summary of what we can do to improve our use of land, reduce emissions and increase our future food security.
Up Next
In the next article, we will dig into each of the 3 components, population change, consumption habits, and climate change, in turn and examine how they affect our climate, and our venerable food system.
