The climate crises humanity is producing due to our profligate burning of fossil fuels is happening in the face of mounting evidence that said burning was very, very bad for the Earth. Some of the problems are now officially going to come even sooner than anticipated. If we want to have a hope of even mitigating these problems, we must change our habits, preferably yesterday.

While burning fossil fuels is a huge part of the problem, food production is also a primary driver of climate change. It is responsible for about 25 to 30 percent of greenhouse gas emissions. Beyond that it also depletes groundwater, converts carbon-sequestering forest and jungle into cropland, and dumps excess nitrogen and phosphorous into soil, water, and air. Under business-as-usual scenarios, these effects will probably at least double by 2050 since the global population is slated to increase by about a third, and the income of the global population is also slated to increase—all of those new and newly rich(er) people are likely going to want to eat and eat well.

At that point, the environmental effects of food production will be “beyond the planetary boundaries that define a safe operating space for humanity.”

There is no quick fix. It will take a combination of different measures to rein in these effects. So says a recent report and analysis in Nature. But these measures are exceedingly ambitious, and, even if they could be pulled off, it looks like we will still be using too much groundwater (into which we will be pouring nitrogen and phosphorous).

Changes

The researchers looked at a few options for changes we could make, assessing their effects on each of the environmental parameters listed above: greenhouse gas emissions, water use, land use, nitrogen application, and phosphorous application. These included dietary changes, reductions in food waste, and improvements in technology. Each of these changes were examined in degrees—for example, they examined reducing meat consumption to three servings per week, as well as one serving per week. (This is relevant because animals account for about 75 percent of the greenhouse gas emissions attributed to agriculture.) They also examined the relative effects of reducing food waste by half and three-quarters (it is estimated that a third—a third!—of all food produced is currently lost or wasted).

The hypothetical improvements in technology, they assessed, would close the gaps between attainable and attained yields by either 75 or 90 percent. These improvements make the most of every acre and enhance fertilization and irrigation efficiency to maximize the use of nitrogen, phosphorous, and water. They only looked at technological fixes “that are considered realistic or attainable, or have been set as goals”—so no soil carbon sequestration, expanded use of nitrogen-fixing bacteria, or additional GMO technology.

They found that we could cut greenhouse gas emissions to amounts that would keep us out of the planetary boundary range if everyone ate not only less meat, but less, period: “lower consumption of meat, staple crops and sugar, and a generally lower energy intake in line with healthy body weights.” We also need to reduce food waste by at least half. These measures coupled with moderate technological innovations could keep us within the mean boundary ranges of water use and cropland use.

But staying below the maximum value of the boundary range for nitrogen and phosphorous application would require not only eating less but also reducing food waste by three-quarters, “ambitious technological improvements,” and “a more optimistic socioeconomic development pathway that includes lower population and higher income growth than is expected at present.”

Caveats

Of course, not only does food production affect the environment; the environment also affects food production. This analysis did not consider how climate change is and will impact things like crop yields and freshwater availability. It also acknowledged, but did not account for, the political and economic reality that investing in efforts to curb climate change caused by factors other than agriculture could limit the resources available to implement the changes outlined here.

Another caveat is that realizing these changes will require investments in public infrastructure and the establishment and enforcement of regulations, and these measures can be almost as difficult to effect as eating less meat. The report suggests that one way to alleviate the effects of a growing population is to make sure that women have information about, and access to, contraception.

Eating à la Michael Pollan—food, not too much, mostly plants—is not only better for your body, it is better for the planet. Who knows, maybe he’s right about LSD, too.

Nature, 2018. DOI: 10.1038/s41586-018-0594-0 (About DOIs).