Pound for Pound, Humanity Proves (Again) to Be a Planet-Altering Colossus

Cross Sections / Abstracts

In our weekly news roundup: A study takes stock of global biomass, the EPA shoves reporters, giant worms invade France, and more.

A common refrain among opponents of climate- and environmental-minded regulation holds that human beings are a mere speck in an otherwise vast, complex, and to some, divinely inspired natural system — far too insignificant to be impacting the planet in any aggregate way.

Sixty percent of all mammals on Planet Earth are cattle, pigs and other livestock.

Visual: Filip Bunkens/Unsplash

While widely embraced within the Trump administration, such thinking, of course, flies in the face of decades of evidence to the contrary, at least where climate change is concerned. And a groundbreaking new study published this week in the Proceedings of the National Academy of Science provides another view of humanity’s outsized footprint — this time by taking stock of the planet’s biomass.

Researchers at Israel’s Weizmann Institute of Science and the California Institute of Technology added up the totality of all plants and animals (including us) on earth, only to find that despite our current global population of 7.6 billion, the human species represents an infinitesimally small share of life. Most living matter, in fact, is plant life — 82 percent, according to the study. Another 13 percent is bacteria. Everything else — bugs, fish, birds, mammals — make up just 5 percent. And those nearly 8 billion humans? They add up to a measly 0.01 percent of all life on earth.

That would seem, at first blush, to comport nicely with the premise of climate skeptics. Such a diminutive species couldn’t possibly alter the fundamental mechanics of a massive, planet-scale machine, right?

Wrong, the new study suggests — very wrong. Indeed, among the most surprising findings was the sheer scale of humanity’s impact on planetary life. Some 83 percent of mammal species and half of all plants have disappeared as human civilization reshaped landscapes with sprawling cities, vast logging and farming operations, mining, and other activities. Two even more shocking data points, as captured by The Guardian: 70 percent of all bird life on the planet is made up of farmed poultry, while 60 percent of all mammals are now cattle, pigs, and other livestock. Humans account for 36 percent of mammal life, meaning that wild mammals — from giraffes and bobcats to bears and kangaroos — account for just 4 percent.

The findings prompted a parade of bleak headlines, from Newsweek (“Humans make up just 0.01 percent of life on earth — but we’re decimating the rest”) to New Scientist magazine (“Half of life on earth has vanished since we arrived on the scene”), though it remains unclear whether the study will change any minds in Washington. Still, the Weizmann Institute scientist who led the analysis remains optimistic. “I would hope this gives people a perspective,” biological physicist Ron Milo told The Guardian, “on the very dominant role that humanity now plays on earth.”

Also in the news:

• A law that aims to ensure access to experimental drug treatments for terminally ill patients is on its way to President Trump’s desk. The “right to try” measure, which passed the Senate last August, had been stalled in the House. But the logjam broke on Tuesday, when 22 Democrats joined 228 Republicans to support it. The law will forbid the government to stop patients from getting drugs that are still unapproved but have been judged safe in humans. (Patients would have to exhaust all other available treatments and be unable to take part in clinical trials.) Forty states already have similar laws, but Trump and other proponents say a federal law is needed to push aside any remaining regulatory obstacles. Critics warn that the law will expose sick patients to “snake oil salesmen” and treatments “that might do more harm than good,” in the words of Rep. Frank Pallone, the New Jersey Democrat who led the opposition in the House. (The Hill)

• Three news organizations unpopular at the Environmental Protection Agency were barred on Tuesday from attending a speech by its administrator, Scott Pruitt. The speech, part of a two-day “leadership summit” on water contamination regulations, was open to other media organizations, but journalists from CNN, the Associated Press, and E&E News were turned away. The EPA at first claimed that it had simply run out of seats for the event, but that was debunked by other reporters; one told Politico that there were “dozens of empty seats in the room.” The AP reported that an EPA guard had forcibly shoved one its reporters out of the room, leading one of Pruitt’s assistants to later apologize. The EPA did decide to allow the reporters back in the pressroom, but only after Pruitt’s talk was done. All three media organizations protested the selective exclusion of journalists assigned to cover an issue of critical national importance. And the boards of the Society of Environmental Journalists and the National Association of Science Writers issued public letters expressing outrage. “When the EPA holds a meeting billed as a forum to share information that directly affects the health of people across the country, it is difficult to understand how the agency can deny entry to journalists that inform the public,” the NASW letter stated. “Americans depend on a free press to inform them about how their government is dealing with an issue that you have called a national priority.” (Snopes)

• If you ask your friend to pass the salt, do you say “thanks” when she does so? If you do, you’re in the minority, according to a new study in the journal Royal Society Open Science. The researchers looked at 928 informal interactions in eight widely disparate languages across five continents, and found that when people complied with a request, they were thanked just 5.5 percent of the time. (The rates were somewhat higher among English and Italian speakers.) But “this does NOT mean that people are universally rude,” wrote the lead author, Nick Enfield, a linguist at the Max Planck Institute for Psycholinguistics in the Netherlands. The gratitude is understood, the researchers concluded, just part of the “social reciprocity” that helps people get along. “Our study reveals an unspoken expectation,” Enfield continued, “that people will cooperate with each other, meaning that thanks are not needed.” (New York Times)

• Scientists have made more aggressive forays into public life since the election of the decidedly anti-scientific Donald Trump, with two marches on Washington (and other cities), and an organized effort to prompt more researchers to set aside the lab coat and run for political office. But two Pennsylvania scientists who answered that call ran into headwinds this month when both lost their campaigns for seats in Congress. Biophysicist Molly Sheehan finished fourth out of 10 candidates in the Democratic primary for the 5th district, in Delaware County, west of Philadelphia; Eric Ding, an epidemiologist, settled for third in a four-person race in the 10th District, which includes Harrisburg and York. The two scientists are still analyzing the election results, but both said fundraising and attracting support from local Democratic committees were challenges. Sheehan, who will return to a position as a postdoctoral researcher at the University of Pennsylvania, said she intends to focus her energies on supporting several Democratic candidates in their bids for state legislature against Republican incumbents. Ding, a former faculty member at the Harvard School of Public Health who is originally from Shippensburg, Pennsylvania, launched his bid late in the game — in February, after district lines were redrawn. Like Sheehan, he plans to endorse the primary winner. (Science)

• And finally: After Pierre Gros, an amateur naturalist in southwestern France, discovered several species of flatworm — including a destructive variety called a hammerhead — in his garden in 2013, scientists put out a public call for images of large worms with broad heads. In a new study co-authored by Gros, researchers revealed the results: Over a four-year period, more than 100 sightings of hammerhead flatworms were delivered by citizen scientists — with one video dating back as far as 1999. That’s cause for concern: The hammerhead — a predatory invader from Asia that can grow up to a foot long and feeds on earthworms and other soil fauna — could potentially alter French biodiversity. “The species are cryptic and soil-dwelling, so it can be easily overlooked,” noted Archie Murchie, an entomologist with Britain’s Agri-Food and Biosciences Institute who was not involved with the study. This, he added, can help explain “their inadvertent shipment round the world.” Of course, such transfers of invasive species are familiar in numerous corners of the globe, a rising trend that shows no sign of abating. Whether there’s a remedy for France’s flatworm problem is unclear, though apparently it should not involve putting one in your mouth. One French scientist recalled a colleague trying to do just that and having “one of the worst experiences of his life.” (Washington Post)