What's the weight of all human-made stuff—products, infrastructure, buildings—created each week? According to a new study published in Nature, the answer is roughly equivalent to the body weight of all people on Earth.
The study marks 2020 as a tipping point: This year, human-made mass (or anthropogenic mass) will exceed the planet's total biomass, which is the mass of all living things. Currently, humans are churning out about 30 gigatons (30,000,000,000 tons) of material a year, and for decades that rate has been growing at a fast clip.
In 1900, for example, anthropogenic mass was just 3 percent of biomass. But every 20 years since, that ratio has at least doubled, gaining pace in more recent decades as industries have been using more geological materials like metals, minerals and rocks.
To measure anthropogenic mass and biomass, the researchers combined previous estimates generated through computer modeling, field surveys and stock-flow modeling, an approach commonly used in macroeconomics research.
It's hard to determine precise figures; imagine trying to weigh all the cars, trees, whales, butterflies, and bacteria across the planet. Making matters more complicated are water and waste.
The researchers didn't include waste in anthropogenic mass estimates, nor did they include water in biomass estimates. Without waste and water included in estimates, anthropogenic mass probably won't exceed biomass for another two decades.
These ballpark estimates highlight humanity's heavy-handed impact on the planet. Our influence is so great that some scientists think we've entered a new epoch: the Anthropocene.
The Anthropocene
In 2000, the atmospheric chemist Paul J. Crutzen proposed that human activity has ushered us into a new geological epoch.
An epoch is a subdivision of geologic timescale. These broad categories help scientists think about changes on Earth over long periods of time. Currently, Earth is considered to be in the:
- Cenozoic Era — 66 million years ago
- Quaternary Period — 2.6 million years ago
- Holocene Epoch — 11,650 years ago
The Holocene Epoch began at about the time when the planet was warming, glaciers were melting, and humans were beginning the agricultural revolution. Scientists like Crutzen argue that it's worth distinguishing the Holocene from our present human-driven epoch, the Anthropocene. (Anthro meaning "human", cene meaning "new".)
Proponents of the concept note that human activity has caused marked changes and damage to the planet, including the sixth mass extinction, the pollution of oceans and the atmosphere, and large-scale changes to the planet's terrain through agriculture, dwellings and industry, which currently cover 70 percent of land.
Elhacham et al.
Not all scientists agree with the idea, and it hasn't been officially accepted by the geological community. These critics generally argue that while humans have left a mark on the planet, it's not significant or observable enough to warrant the creation of a new epoch. And some take issue with the political motivations that may underlie the concept.
"The proliferation of this concept can mainly be traced back to the fact that, under the guise of scientific neutrality, it conveys a message of almost unparalleled moral-political urgency," wrote the German philosopher Peter Sloterdijk.
Still, the researchers behind the recent study said the findings give "a mass-based quantitative and symbolic characterization of the human-induced epoch of the Anthropocene."
Concrete
But never mind the Anthropocene or Holocene debate: It's clear that humans are producing a ton of stuff, and that stuff eventually becomes waste. So, what are policymakers and scientists supposed to do with this information?
The recent findings don't necessarily hold an answer, but they do highlight the single largest contributor to total human-made stuff: concrete. It's the most widely used material on Earth, and also one of the main culprits in emissions of greenhouse gas.
A 2020 study published in Nature found that, in terms of total emissions contributions, concrete production is responsible for "7.8% of nitrogen oxide emissions, 4.8% of sulfur oxide emissions, 5.2% of particulate matter emissions smaller than 10 microns and 6.4% of particulate emissions smaller than 2.5 microns."
"If we invented concrete today, nobody would think it was a good idea," said architectural engineer and panel member Michael Ramage, an architectural engineer and member of Architecture of Emergency, at a 2019 summit. "We've got this liquid and you need special trucks, and it takes two weeks to get hard. And it doesn't even work if you don't put steel in it."
In 2018, the Global Cement and Concrete Association issued six Sustainability Guidelines to encourage better practices for the 30 percent of the cement and concrete production companies it represents. Still, it's unclear the extent to which the industry could make itself more sustainable.
One sustainable alternative building material to concrete is cross-laminated timber, which is as strong as concrete, but is able to store carbon, which could help lower the carbon footprint of buildings.
Walmart recently announced plans to battle Amazon in the massive online shopping market. At $98/year, Walmart+ offers many of the same perks, including same-day grocery delivery, as well as discounts at Walmart gas stations, one of the few things Amazon cannot offer (yet). Of course, it lacks the entertainment perks of Amazon Prime, such as the automatic subscription to numerous TV shows and movies.
Another important distinction: Walmart is offering discounts on fossil fuels while Amazon has promised to create a fleet of 100,000 electric delivery vans in order to become completely carbon neutral by 2040. That said, Walmart does have plans for reducing its carbon footprint as well. Unfortunately, these ambitious plans likely won't impact harmful consumer habits, which are rooted in the conveniences that online retailers offer.
Earlier this year, a study from researchers in the Netherlands, Sweden, and the UK, published in the journal Environmental Science & Technology, confirmed what many expected: online shopping is worse for the environment than going to the store yourself. This contradicts previous research championing online shopping.
While Amazon boasts of its greening efforts, the corporation's current protocols are horrendous. Many packages are glorified Matryoshka dolls. I recently ordered a three-inch cable that arrived wrapped in two boxes, padded by three layers of brown wrapping paper and plastic.
There seems to be no uniform shipping policies. Some books arrive in white padded envelopes, others in thin brown envelopes, some in boxes. While supply chain management is tricky, a company cannot both claim to be environmentally friendly and notoriously unreliable. Online retailers bank on convenience, not being stewards of nature.
The researchers investigated production distribution disparities in fast-moving consumer goods (FMCGs), such as personal care and home care products, between physical stores, "bricks and clicks" (fulfillment via physical store deliveries), and non-store-based e-commerce sites, known as "pure players." They conclude that the latter considerably increases greenhouse gas (GHG) footprints.
A pile of recycled cardboard sits on the ground at Recology's Recycle Central on January 4, 2018 in San Francisco, California.
Photo by Justin Sullivan/Getty Images
A large part of the reason is speed. In a competitive market, pure players use the equation, speed + convenience, to drive adoption. This is especially relevant to the "last mile" GHG footprint: the distance between the distribution center and the consumer.
Interestingly, the smallest GHG footprint occurs when you order directly from a physical store—even smaller than going there yourself. Pure players, such as Amazon, are the greatest offenders. Variables like geographic location matter; the team looked at shopping in the UK, the US, China, and the Netherlands.
Sadegh Shahmohammadi, a PhD student at the Netherlands' Radboud University and corresponding author of the paper, says the above "pattern holds true in countries where people mostly drive. It really depends on the country and consumer behavior there."
The researchers write that this year-and-a-half long study pushes back on previous research that claims online shopping to be better in terms of GHG footprints.
"They have, however, compared the GHG emissions per shopping event and did not consider the link between the retail channels and the basket size, which leads to a different conclusion than that of the current study."
Online retail is where convenience trumps environment: people tend to order one item at a time when shopping on pure player sites, whereas they stock up on multiple items when visiting a store. Consumers will sometimes order a number of separate items over the course of a week rather than making one trip to purchase everything they need.
While greening efforts by online retailers are important, until a shift in consumer attitude changes, the current carbon footprint will be a hard obstacle to overcome. Amazon is trying to have it both ways—carbon-free and convenience addicted—and the math isn't adding up. If you need to order things, do it online, but try to consolidate your purchases as much as possible.
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Stay in touch with Derek on Twitter, Facebook and Substack. His next book is "Hero's Dose: The Case For Psychedelics in Ritual and Therapy."
