Throwing Our Weight Around on Planet Earth

    You may have heard the shockingly depressing statistic, popularized in David Attenborough’s moving documentaries, that humans and our livestock now account for an incredible 98 percent of the biomass of all land mammals on the planet. We are roughly a third, our livestock two thirds. If you include sea mammals, that number only drops to 96 percent. A mere four percent wild, in all the vast continents and oceans of the globe. It paints a sad picture of an Earth overrun with humanity, having succumbed almost completely to our civilizing influence. The world domesticated. Nature tamed. For anyone who values the wild, and the profound sense of awe and wonder that encounters with it embody, this is a tragedy of almost unbearable proportions.

    And while we are saddened by this sobering statistic, we are also not that surprised. It fits with our exceptionalist narrative of humans as the clear masters of the world. We are changing the temperature of the entire planet, after all. One of the most overused environmental motifs is that of a hand holding a pile of soil with a green plant sprouting from it. It is meant to convey the idea that we figuratively hold the fate of life on Earth in our hands. We have basically made of ourselves God. The only question that remains is whether we’ll be a kind and loving God to all creation, or a selfish and destructive one.

    But a different set of statistics I recently came across upended this picture for me. I found them in various articles written on the website, much of it based on a 2018 paper called The Biomass Distribution on Earth. In it, it shows that if you put us on a giant scale – all 7.9 billion of us – we would still only add up to 0.01 percent of the weight of everything alive. What’s really tipping the scales? Plants, mostly trees, make up 82 percent. In distant second place is bacteria, at 13 percent. Observant readers will notice we’re already at 95 percent. That means the last 5 percent is made up of everything else: fungi, other non-bacteria microbes, and animals. Even miniscule viruses add up to four times more weight than humans. No wonder they give us so many problems.

    Alright, you say, we may commune with the trees, and a few of us may be mushroom crazy, but for the most part it’s our fellow animals, especially mammals, that we care most about. While the animal kingdom only accounts for half a percent of the biomass of all life, maybe it’s within that category that we should be making comparisons.

    Humans sit at about 2 percent of animal biomass. Almost double that is the family that includes jellyfish and corals. More than three times our weight each is the mollusk family (mostly snails and slugs), annelids (mostly worms and leeches), and insects. Rounding out the hierarchy of animals on Earth are fish at 27 percent and marine arthropods (crabs, shrimp, krill) at 39 percent – enough to secure a majority in Canada’s outdated electoral system. If humanity were a political party in the parliament of Earth, we wouldn’t even be granted party status. The only wild animals less than us are nematodes, mammals, and birds.

    Take what you like from the above statistics. Personally, I find it both hopeful and humbling that we are not the lords of the castle we thought we were. Yes, we do have an outsized impact on the mammals and birds we feel the most kinship with, and we should do our utmost to reverse the terrible damage we have inflicted on their numbers. But the world is still buzzing with life – much of it considered beneath our notice, but essential to the continual functioning of life on this planet. And no matter what good or bad choices we make as a species in the next few decisive decades, life will continue to find a way to thrive on Earth. Environmentalism is really about what future we choose for ourselves – a tiny species living in the vast web of life.

    2 thoughts on “Throwing Our Weight Around on Planet Earth”

    1. Another great article, Sean, to set us thinking. Thank you. You do these things so well

    2. I had no idea other forms of life weigh so much more than human mass. It’s an unusual but interesting statistic and, as you state, conveys that we are much less important than we might have thought, at least when it comes to the total weight of species. The incredibly low, and hitherto, relatively unknown power/weight ratio of human beings further underscores our species’ outsized influence for good and bad. It reveals a scope of potential mass destructiveness far greater than we might have imagined. We must re-wild the planet and civilize our civilization so that it too may, like the biosphere, become sustainable and continue to evolve new life.

    Comments are closed.