Humans Are Less Than 1% of Life on Earth—But We've Killed Most of the Other 99%

Tuesday, 22 May 2018 - 11:06AM
Tuesday, 22 May 2018 - 11:06AM
Humans Are Less Than 1% of Life on Earth—But We've Killed Most of the Other 99%
< >
Image credit: Unsplash/Outer Places

As a famous wordsmith once said: "Men lie, women lie, numbers don't." The argument that humans have contributed greatly to the current state of the world is not new, but for some, it matters who is making the argument and why. 


Things like religion and political agendas often overshadow the message, but it's a lot harder to argue with fractions and decimals. A new article published in Proceedings of the National Academy of Sciences breaks down Earth's biomass distribution, and when you look at the role humans have played in the grand scheme of things, it is a bit alarming.

Looking at the data, The Guardian reports that while the 7 billion humans on this planet represent 0.01% of Earth's biomass (tiny compared to the 13% made up of bacteria and the 83% that plants represent), we have collectively caused the loss of 83% of the wild animals and 50% of the plants that once shared this rock.


As for livestock that we grow for food and materials, those numbers are up. Farmed chickens and other poultry are 70% of the planet's birds, and 60% of all the mammals in existence are grown and kept by people.

"I was shocked to find there wasn't already a comprehensive, holistic estimate of all the different components of biomass," said Professor Ron Milo of Weizmann Institute of Science in Israel who led the study. "It is pretty staggering...In wildlife films, we see flocks of birds, of every kind, in vast amounts, and then when we did the analysis we found there are more domesticated birds."


Milo and his team say that the human impact began "long before present times," but we have clearly made things worse. Estimates place the current tree count, for example, at half of what it was before human civilization. 

"It is definitely striking, our disproportionate place on Earth," Milo said.


"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."


Milo says that he has chosen to eat less meat after learning about the impact livestock has on the planet.


After skimming the 113-page research paper, we can't deny that some things don't add up. We probably won't all be joining in Milo's new diet, but we do recommend taking a peek at the numbers yourself because they are very interesting.

Science News