Is CO2 the only carbon we should be focused on?
Is CO2 the only carbon we should be focused on? The food and agriculture declaration recently signed by more than 130 world leaders at the United Nations COP28 meeting in Dubai is long overdue recognition of agriculture as a component of addressing climate change. While it’s no surprise that the declaration, which for the first time formally addressed the climate change contributions and vulnerabilities of this sector, was announced in a desert nation that imports approximately 80 percent of its food, why did it take 28 of these meeting to recognize something so fundamental?
Some of this may be due to agriculture’s complex relationship with carbon. The sector consumes atmospheric carbon (CO2) through photosynthesis, contributes about one-third of greenhouse gas emissions, and is a major source of crucial new carbon (food) for all life on earth. The most difficult complication, however, may be yet to come: the ongoing supply of this “new” agricultural carbon is more constrained than fossil fuels ever were. Much of the world still seems to be acting like there is an endless supply of affordable plants that will not only feed us but also help us counter climate change.
Nowhere is this dissonance clearer than in the continuing attempts to expand the use of agriculture as a direct “decarbonizing” substitute for fossil fuels, such as biofuels and so-called green petrochemicals. Even most of the new genetically engineered refining technologies, which feed sugar to bacteria to make end-products, assume a stream of plant-based feedstock. The growing issue is that much of this innovation involves new uses for plantbased carbon, not new sources. And the earth’s capacity for generating new plant supply may be as limited as its ability to absorb all the excess CO2 that has been released by burning their fossilized ancestors.
Why hasn’t this looming supply crisis gotten more attention? Before we worried about oil and gas emissions, we mostly worried about their supply. A popular theory, known as “peak oil,” even postulated that we had identified all the economical oil we would ever be able to find. In the end, the more mainstream view that “the stone age did not end because we ran out of rocks” held true for oil. In agriculture, however, there is a reasonable chance we could run out of land.
Unlike oil and gas, agriculture is a manufacturing process, not a treasure hunt. It relies on a scarce resource — land — to capture free sunlight and water. A giant agricultural reserve will not be suddenly discovered in the same way we used to unearth “super-giant” oil fields. We have been able to meet our growing needs mostly by clearing more land (often at the expense of CO2-eating forests) and applying more fossil fuel-based fertilizers to increase yields. Neither approach is sustainable, and while there has been progress in finding substitutes for petrochemical fertilizers, land is another thing entirely.
Experts have cautioned that the clock is running out on the 10,000-year-old agricultural approach. The World Resources Institute estimates we need additional land equivalent to nearly the area of Australia, while reducing emissions by about twothirds, just to meet both the world’s expected food requirements and CO2 reduction targets by 2050. And this is before the use of plants instead of oil to make sneakers and gasoline — not to mention it takes much more land to generate the same amount of carbon from plants than to produce oil.
In addition, several other decarbonization efforts in energy, such as wind and solar, also may require additional land and agriculture and solar both seek land with superior access to sunshine.
So where will we get all this new and affordable plant-based carbon? Supply security for crude oil has been a cornerstone of geopolitics since World War II. How do we even begin to think about supply security for plants?
In many ways, in much the same way. Solutions are already being identified that are thematically similar to those in energy, such as increasing the efficiency, resiliency, and yields of existing agricultural supply or reducing demand through better distribution, storage, waste reduction, and changing personal habits (like eating less meat).
And while there is precious little new arable land currently unoccupied by people or forests, technology is rapidly advancing in concentrated indoor agriculture, which can “create” land by stacking it vertically, like a skyscraper, is insulated from climate change, and can be deployed in most any geography, provided its energy-use shortcomings can be solved.
Like the rest of the COP28 agenda, however, these challenges and solutions are as political as they are technological. Imagine the sort of difficult choices countries would have had to make if “peak oil” had been true, and supplies had started to run out before economies had prepared the transition to alternatives. Yet this is effectively the world we could face in agriculture given shrinking land resources, especially as disruptions such as flooding, drought, and excessive heat from climate change continue to escalate.
As the delegates at COP28 look out from Dubai’s skyscrapers (some built on artificially created land in the ocean) over the sparsely vegetated but hydrocarbon-rich desert, eating their imported food, there are some complex trade-offs to consider. Should scarce land be used for human food crops, animal feed, livestock, rewilded forests, corn-based gasoline, green petrochemicals, or solar panels, to name a few? Answering these questions must start by recognizing the full extent and complexity of these land limitations. “Peak oil” never happened because cuttingedge technology kept sharpening and expanding our underground vision, enabling us to discover more. “Peak land” is another thing entirely; an old map is all we need to see where it ends.