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Humans and Big Ag Livestock Now Account for 96 Percent of Mammal Biomass
A first-of-its-kind study published Monday shows that, when it comes to impacting life on Earth, humans are punching well above our weight.
The study, published in Proceedings of the National Academy of Sciences, is the first ever comprehensive census of the distribution of the biomass, or weight of living creatures, across classification type and environment. It found that, while humans account for 0.01 percent of the planet's biomass, our activity has reduced the biomass of wild marine and terrestrial mammals by six times and the biomass of plant matter by half.
"I would hope this gives people a perspective on the very dominant role that humanity now plays on Earth," lead researcher and Weizmann Institute of Science in Israel professor Ron Milo told The Guardian.
According to the study, human impacts are due to the combined effects of the agricultural and industrial revolutions. In particular, the domestication of livestock has caused a shift in the relative biomass of different species of mammals.
Humans account for about 36 percent of the biomass of all mammals. Domesticated livestock, mostly cows and pigs, account for 60 percent, and wild mammals for only 4 percent.
The same holds true for birds. The biomass of poultry is about three times higher than that of wild birds.
"It is definitely striking, our disproportionate place on Earth," Milo told The Guardian. "When I do a puzzle with my daughters, there is usually an elephant next to a giraffe next to a rhino. But if I was trying to give them a more realistic sense of the world, it would be a cow next to a cow next to a cow and then a chicken."
The study further broke down the human impact on terrestrial and marine mammals. Compared to the time before the human-abetted extinction of large megafauna, wild earth mammal biomass has decreased sevenfold. Marine mammal biomass has decreased fivefold due to commercial whaling and other exploitative hunting practices. Fish biomass has also fallen around 15 percent.
Humans and their livestock have increased the total biomass of mammals by a factor of four and they outweigh all vertebrates besides fish.
Milo told The Guardian that the results had encouraged him to reconsider his eating habits.
"I would hope people would take this [work] as part of their world view of how they consume," he said. "I have not become vegetarian, but I do take the environmental impact into my decision making, so it helps me think, do I want to choose beef or poultry or use tofu instead?"
When it comes to the biomass of all life on earth, humans and their livestock are barely a blip. They only account for 8 percent of total animal biomass, while arthropods account for 50 percent.
Overall, animals have nothing on the other other kingdoms. Plants dominate, accounting for about 80 percent of all of the earth's biomass, followed by bacteria at about 15 percent.
Since most plants are terrestrial, the study found that most of earth's biomass is found on land, but most animal biomass is found in the oceans.
Biomass is different from biodiversity—insects, for example, contain a wide variety of species but account for a tiny percentage of biomass.
Researchers calculated biomass in gigatons of carbon and compiled data from a wide variety of studies to reach their conclusions.
- Earth Is Not in the Midst of a Sixth Mass Extinction - The Atlantic ›
- Industrial farming is driving the sixth mass extinction of life on Earth ... ›
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‘Companies Should Not Be Allowed to Use Hazardous Ingredients in Products People Use’: Michelle Pfeiffer Speaks Up for Safer Cosmetics
The beauty products we put on our skin can have important consequences for our health. Just this March, the U.S. Food and Drug Administration (FDA) warned that some Claire's cosmetics had tested positive for asbestos. But the FDA could only issue a warning, not a recall, because current law does not empower the agency to do so.
Michelle Pfeiffer wants to change that.
The actress and Environmental Working Group (EWG) board member was spotted on Capitol Hill Thursday lobbying lawmakers on behalf of a bill that would increase oversight of the cosmetics industry, The Washington Post reported.
By Julia Conley
Scientists at the United Nations' intergovernmental body focusing on biodiversity sounded alarms earlier this month with its report on the looming potential extinction of one million species — but few heard their calls, according to a German newspaper report.
The climate crisis is a major concern for American voters with nearly 40 percent reporting the issue will help determine how they cast their ballots in the upcoming 2020 presidential election, according to a report compiled by the Yale Program on Climate Change Communication.
Of more than 1,000 registered voters surveyed on global warming, climate and energy policies, as well as personal and collective action, 38 percent said that a candidate's position on climate change is "very important" when it comes to determining who will win their vote. Overall, democratic candidates are under more pressure to provide green solutions as part of their campaign promises with 64 percent of Democrat voters saying they prioritize the issue compared with just 34 percent of Independents and 12 percent of Republicans.
President Donald Trump has agreed to sign a $19.1 billion disaster relief bill that will help Americans still recovering from the flooding, hurricanes and wildfires that have devastated parts of the country in the past two years. Senate Republicans said they struck a deal with the president to approve the measure, despite the fact that it did not include the funding he wanted for the U.S.-Mexican border, CNN reported.
"The U.S. Senate has just approved a 19 Billion Dollar Disaster Relief Bill, with my total approval. Great!" the president tweeted Thursday.