A new paper in Proceedings of the National Academy of Sciences has measured the "trophic level" of human beings for the first time. Falling between 1 and 5.5, trophic levels refer to where species fit on the food chain. Apex predators like tigers and sharks are given a 5.5 on trophic scale since they survive almost entirely on consuming meat, while plants and phytoplankton, which make their own food, are at the bottom of the scale. Humans, according to the new paper, currently fall in the middle: 2.21. However, rising meat-eating in countries like China, India, and Brazil is pushing our trophic level higher with massive environmental impacts.
A new paper in Proceedings of the National Academy of Sciences has measured the "trophic level" of human beings for the first time. Falling between 1 and 5.5, trophic levels refer to where species fit on the food chain. Apex predators like tigers and sharks are given a 5.5 on trophic scale since they survive almost entirely on consuming meat, while plants and phytoplankton, which make their own food, are at the bottom of the scale. Humans, according to the new paper, currently fall in the middle: 2.21. However, rising meat-eating in countries like China, India, and Brazil is pushing our trophic level higher with massive environmental impacts.
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"In the global food web, we discover that humans are similar to anchovy or pigs and cannot be considered apex predators," the researchers write in the new paper.
Using data from the Food and Agricultural Organization (FAO) going back nearly 50 years, the scientists find that the human trophic level has risen from around 2.15 in the 1970s to 2.21 today. Trophic levels are on the rise in many developing countries as economies have expanded and millions have come out of poverty. However, the change has come with drastic environmental impacts: meat-eating is less-efficient than a plant based diet and, as such, generally requires far more land, water, and energy to produce the same amount of calories.
The new study also evaluated human trophic levels (HTL) country-by-country, and found, not surprisingly, a wide variation in trophic levels across the world.
"In 2009, Burundi had an [human trophic level (HTL)] of 2.04, representing a diet that is almost completely (96.7 percent) plant based. In contrast, Iceland had an HTL of 2.57 for the same year, representing a diet composed of 50 percent meat and fish and 50 percent plants," the researchers write.
The scientists also found that a country's trophic levels generally corresponded to World Bank development indicators.
"[Human trophic level] is positively related to, for example, gross domestic product, life expectancy, CO2 emissions, and urbanization rate until a point after which the relationships plateau and then turn negative," write the researchers.
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Meat image via Shutterstock.
