Study Sheds Light on Environmental Impact of Global Food Production

Summary

New research pub­lished in Nature Sustainability exam­ines the envi­ron­men­tal impacts of global food pro­duc­tion, with a focus on fresh­wa­ter con­sump­tion, green­house gas emis­sions, habi­tat dis­tur­bance, and nutri­ent pol­lu­tion. The study found that meat pro­duc­tion and rice, wheat, and oil crops have the worst envi­ron­men­tal impacts, and that the U.S., China, India, Brazil, and Pakistan account for half of the global envi­ron­men­tal impact of food pro­duc­tion. Lead author Ben Halpern hopes the research will guide pol­i­cy­mak­ers and con­sumers towards more sus­tain­able food choices.

New research pub­lished in Nature Sustainability details the impacts of global food pro­duc­tion on the envi­ron­ment.

Its lead author believes that the four-year inves­ti­ga­tion – which used a 2017 United Nations report to exam­ine nearly 99 per­cent of global food pro­duc­tion on land and sea – offers peo­ple a way to eval­u­ate how their eat­ing pat­terns affect the planet and a sus­tain­able path­way to fight­ing hunger.

“This infor­ma­tion helps us think bet­ter about the food we eat and the envi­ron­men­tal pres­sure it has on our planet,” Ben Halpern, the direc­tor of the University of California-Santa Barbara’s National Center for Ecological Analysis and Synthesis, told Olive Oil Times. ​“The dif­fi­cult news is it takes a lit­tle bit of work to think care­fully about your diet.”

Using fresh­wa­ter con­sump­tion, green­house gas emis­sions, habi­tat dis­tur­bance and nutri­ent pol­lu­tion, the researchers com­pared the cumu­la­tive envi­ron­men­tal impact of pro­duc­ing one pound or kilo­gram for a wide range of foods.

However, Halpern said that the team could not con­sider every envi­ron­men­tal fac­tor, such as defor­esta­tion, pes­ti­cide use and soil fer­til­ity degra­da­tion, due to a lack of data. Additionally, pos­i­tive envi­ron­men­tal impacts, such as the seques­tra­tion of car­bon diox­ide by tree crops, were not con­sid­ered.

“What we have here is a con­ser­v­a­tive esti­mate of those pres­sures because there are impor­tant fac­tors miss­ing,” he said.

The study’s results demon­strated that meat pro­duc­tion from cows and pigs and rice, wheat and oil crop pro­duc­tion have the worst envi­ron­men­tal impacts. However, how they neg­a­tively impact the envi­ron­ment is very dif­fer­ent.

The researchers found that 60 per­cent of the cumu­la­tive impact of rais­ing cat­tle for beef comes from green­house gas emis­sions, with another 31 per­cent attrib­uted to nutri­ent pol­lu­tion and feed pro­duc­tion.

Meanwhile, most of the impacts of rice and wheat crops resulted from habi­tat dis­tur­bance and the immense amount of fresh water used.

Overall, global food pro­duc­tion uses about 50 per­cent of Earth’s hab­it­able sur­face area, more than 70 per­cent of avail­able fresh­wa­ter and emits between 23 and 34 per­cent of human-caused green­house gas emis­sions.

“Unfortunately, we weren’t able to dis­ag­gre­gate the infor­ma­tion into spe­cific prod­ucts,” Halpern said. As a result, olive oil pro­duc­tion was grouped into a larger cat­e­gory with canola, cot­ton seed, sesame seed and sun­flower oils.

“We don’t know the indi­vid­ual con­tri­bu­tion of each of those oil types because they’re not reported,” he added.

However, Halpern said the scale of pro­duc­tion is an impor­tant fac­tor to keep in mind, as widely planted crops will take up more resources.

As a result, he sug­gested that olive oil pro­duc­tion has a rel­a­tively low envi­ron­men­tal impact com­pared to other inten­sively grown oilseed crops.

“Annual crops take a lot more water and a lot more land, so they are likely to have higher envi­ron­men­tal pres­sures than olive oil,” Halpern said.

While the researchers did not take car­bon seques­tra­tion into account, pre­vi­ous stud­ies have found that all three cat­e­gories of olive groves – tra­di­tional, high-den­sity and super-high-den­sity – act as car­bon sinks.

In a 2021 study, researchers from the University of Jaén, Spain, found tra­di­tional rain­fed olive groves sequester an esti­mated 5.5 kilo­grams of car­bon diox­ide for each kilo­gram of olive oil pro­duced. This fig­ure falls to 4.3 in irri­gated olive groves.

Meanwhile, high-den­sity and super-high-den­sity olive groves sequester 2.7 kilo­grams of car­bon diox­ide per kilo­gram of olive oil pro­duced.

Along with study­ing the impacts of each type of food pro­duc­tion on the envi­ron­ment, the researchers also looked at food pro­duc­tion impacts in each coun­try.

They found that five coun­tries account for half of the global envi­ron­men­tal impact of food pro­duc­tion: the U.S., China, India, Brazil and Pakistan.

The researchers also found that coun­tries pro­duce the same food with dif­fer­ent envi­ron­men­tal impacts.

For exam­ple, they found the U.S. is 2.4 times more effi­cient than India at pro­duc­ing soy due to the use of tech­nol­ogy to reap higher yields with fewer green­house gas emis­sions. The U.S. is the world’s largest soy pro­ducer, and India is the fifth-largest.

A sim­i­lar trend was seen for dem­er­sal fish, which live and feed on the ocean floor, with Russia har­vest­ing these fish 1.5 times more effi­ciently than China and 1.9 times more effi­ciently than Brazil.

“That’s one of the really pow­er­ful things we’ve done with these analy­ses by being able to map where things occur and the dif­fer­ences in the envi­ron­men­tal pres­sures in pro­duc­tion in dif­fer­ent places,” Halpern said.

“Each coun­try has dif­fer­ences in how good or bad they are at pro­duc­ing food,” he added. ​“So you can start under­stand­ing those dif­fer­ences and maybe make choices based on those dif­fer­ences.”

Halpern orig­i­nally started the project to sati­ate his innate curios­ity about the envi­ron­men­tal impact of his diet.

After read­ing myr­iad news reports about the sig­nif­i­cant impact of meat pro­duc­tion on green­house gas emis­sions, he became a pescatar­ian.

However, he quickly real­ized that while many of the news reports were based on sci­en­tific stud­ies, none of them took into account the other envi­ron­men­tal impacts of food pro­duc­tion.

Now that this study is com­plete, Halpern hopes it will help guide pol­i­cy­mak­ers and indi­vid­ual con­sumers to make informed deci­sions about sus­tain­able food pro­duc­tion.

“It would be won­der­ful if our work can help inform changes to the Farm Bill or, at an inter­na­tional level, trade pol­icy that struc­tures incen­tives for dif­fer­ent food pro­duc­tion,” he said.

“If we care about a sus­tain­able food sys­tem and healthy peo­ple, we need to rethink a lot of the details [about where and how food is pro­duced],” he added. ​“If our results could help inform some of those changes, that would be a pro­foundly wel­come out­come.”

Halpern is cur­rently fol­low­ing this research up with another study on the envi­ron­men­tal jus­tice impli­ca­tions of the impacts of food pro­duc­tion.

“We hear this a lot in terms of like fac­tory pol­lu­tion as an exam­ple of where these harm­ful human health out­comes are dis­pro­por­tion­ately affect­ing minori­ties and under­rep­re­sented groups,” he said.

“Our work is start­ing to explore if or how these envi­ron­men­tal food pres­sures may be hav­ing sim­i­lar con­se­quences for peo­ple around the planet,” Halpern con­cluded.