How humans have killed off most wildlife
Since the dawn of civilization, mankind has wiped out an astonishing 83 percent of all wild mammals on Earth, and half of all plants—while filling the planet with domesticated animals bred for eating. That’s the conclusion of a major, first-ofits-kind attempt to measure the overall footprint of all earthly life, reports The Guardian (U.K.). Using data from hundreds of previous studies, researchers estimated that the planet’s living creatures contain a total of about 550 billion metric tons of carbon. The 7.6 billion people in the world account for only 0.01 percent of this biomass—about the same as termites. Plants make up 82 percent, and bacteria 13 percent. Even viruses, worms, and fungi cumulatively outweigh people. But despite our physical insignificance, humans have a broad footprint: Deforestation, farming, hunting, and other human activities have taken an outsize toll on all other kingdoms of life. Domesticated livestock, such as pigs and cattle, now account for 60 percent of the biomass of all mammals on Earth; wild animals make up only 4 percent. Seventy percent of birds on the planet are farmed poultry. The study should serve as a reminder of the impact human consumption has on Earth, says lead researcher Ron Milo, from Israel’s Weizmann Institute of Science. “Our dietary choices have a vast effect on the habitats of animals, plants, and other organisms.”