May 22nd, 2018
Ever wonder how much mass the entirety of Earth’s lifeforms weigh? No? Well, scientists definitely do, and a new study published in the Proceedings of the National Academy of Sciences offers the surprising answer. Every living thing on Earth — from the tiniest bacteria to a mighty redwood tree — weighs a combined 550 gigatons when removing water from the equation. Yeah, that’s a lot.
One gigaton is equal to one trillion metric tons, to give you an idea of just how much mass we’re talking about here, but you’re probably going to be surprised by how little humans contribute to that total. As it turns out, the combined weights of many different classes of animals outweighs humans by a huge margin. Fish, for example, weigh roughly 0.7 GT C (gigatons of carbon), while viruses weigh around 0.2 GT C. Humans weigh even less than that.
According to the research, the combined weight of humans comes in at approximately 0.06 GT C. We’re outweighed by almost everything, including bacteria (70 GT C), fungi (12 GT C), arthropods (1 GT C), Mollusks (0.2 GT C), and even our own livestock (0.1 GT C). When combined, the mass of humans and their livestock outweigh wild mammals by a huge margin, with wild mammals only accounting for 0.007 GT C. In fact, all of the animal kingdom only accounts for a measly two gigatons overall.
The biggest heavyweight? Plants, of course! Plants account for an absolutely mind-boggling 450 GT C. That’s every tree, blade of grass, vine, veggie, and floating clump of algae, among many other things.
To arrive at these figures, scientists spent three years calculating the biomass of every living thing and feeding that data into their census. They initially intended to discover the amounts of different proteins present on the planet — the scientists will be working more on that soon — but in order to do so they had to also figure out how much all life on Earth weighs, which is probably a more interesting data point for most casual science fans.
It’s important to remember that just because we make up a tiny chunk of the life on the planet, that doesn’t mean we aren’t still responsible for the greatest impact on the environment. Despite making up a fraction of a percent of the weight of life, our buildings, vehicles, and other manmade creations — including our never-ending supply of garbage — multiply our impact in a huge way.