By Biomass, Humans Have Eliminated Half of the World’s Plants and Over 80% of the World’s Wild Mammals

Staggering statistics, being a warning that humans can eliminate their own species at scale (through nuclear weapons or climate change, for instance) if they fail to be careful enough.

While scientists and conservationists grow increasingly worried about the world’s biodiversity, a new study that sought to estimate the biomass of all living creatures on Earth has shed some light on humanity’s impact.

The planet is largely dominated by plants, which make up 82 percent of all life on Earth, followed by bacteria at 13 percent, and the remaining five percent is everything else, including 7.6 billion human beings.

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According to the study, published Monday by the Proceedings of the National Academy of Sciences of the United States of America (PNAS), people only make up 0.01 percent of the Earth’s biomass—however, their impact has been massive.

The researchers estimate that, in terms of biomass, the so-called rise of human civilization has destroyed 83 percent of wild mammals, 80 percent of marine animals, 50 percent of plants, and 15 percent of fish.

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Plants Can Absorb Toxins, Increasing Indoor Air Quality

Air quality is an important aspect of indoor environments, yet there is surprisingly little research on optimizing the role of plants for increasing that air quality, and even how plants can absorb indoor toxins doesn’t seem widely known.

People in industrialized countries spend more than 80% of their lives indoors, increasingly in air-tight buildings. These structures require less energy for heating, ventilating, and air conditioning, but can be hazardous to human health if particulate matter and potentially toxic gases, including carbon monoxide, ozone, and volatile organic compounds, from sources such as furniture, paints, carpets, and office equipment accumulate. Plants absorb toxins and can improve indoor air quality, but surprisingly little is known about what plants are best for the job and how we can make plants perform better indoor.

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Plants improve air quality through several mechanisms: they absorb carbon dioxide and release oxygen through photosynthesis, they increase humidity by transpiring water vapor through microscopic leaf pores, and they can passively absorb pollutants on the external surfaces of leaves and on the plant root-soil system. But plants are usually selected for indoor use not for their air-purifying abilities but for their appearance and ability to survive while requiring little maintenance.