While there has been an increasing public focus on climate change in the past few years, and a slow awakening to the threat it poses, we have yet to wake up fully to an even bigger problem. I noted in a September column that we face not only a climate emergency but an extinction emergency.
A 2018 article in the Proceedings of the National Academy of Sciences sheds light on this. It reported on a census of the biomass of the Earth — the weight (measured as carbon) of all living things. Just over 80 per cent is plants, while another 12 per cent or so is bacteria; fungi make up about two per cent and the entire animal kingdom makes up less than 0.4 per cent of the Earth’s biomass.
Within the minuscule fraction that is the animal kingdom, about half the biomass is marine arthropods, with most of that being crustacea (e.g. crabs, shrimps, lobsters and Antarctic krill) and another 35 per cent is fish. Land vertebrates are only about 0.03 per cent (three ten-thousandths) of the weight of all living things, with humans making up about one third of that (0.01 per cent). We are outweighed by our livestock, and roughly matched by both Antarctic krill and termites. That should make us feel small and humble!
But while small, we are also mighty. The article notes it has been estimated that “the present-day biomass of wild land mammals is approximately sevenfold lower” than it was 50,000 years ago, before we started wiping out the large land mammals. As a result, we now outweigh wild animals tenfold.
They also report that our hunting of whales and other marine mammals has led to a roughly fivefold decrease in their biomass, while we have roughly halved total fish biomass.
It’s not just animals that we have harmed; the authors point to evidence suggesting “the total plant biomass [and, by proxy, the total biomass on Earth] has declined approximately twofold relative to its value before the start of human civilization.” Given that plants make up roughly 80 per cent of the total biomass, that is an astonishing level of impact, one that is not compensated for by our crops, which, they report, account for only about two per cent of total plant biomass.
Small wonder, then, that the International Union for the Conservation of Nature reports there are more than 28,000 species threatened with extinction, which is 27 per cent of all the species they have assessed. This includes four in 10 assessed amphibian species, one quarter of all mammals, almost a third of the sharks and rays and in the plant kingdom, a third of conifers and more than half Europe’s endemic trees.
Contemplating what amounts to a holocaust in the animal and plant kingdoms, the famous 1946 confession of the German Lutheran pastor Martin Niemöller came to mind: “First they came for the socialists, and I did not speak out — because I was not a socialist. Then they came for the trade unionists, and I did not speak out — because I was not a trade unionist. Then they came for the Jews, and I did not speak out — because I was not a Jew. Then they came for me — and there was no one left to speak for me.”
In the face of this sixth Great Extinction of life that humanity has initiated, I think we need an updated version, a lament for the web of life:
“First they came for the whales and the sharks, the salmon and the cod and I did not speak out — because they were but sea creatures. Then they came for the elephants and the tigers, the rhinos and the bears, and I did not speak out — because they were only animals. Then they came for the birds and the insects, the reptiles and the frogs, and I did not speak out — because they were small and unimportant. Then they came for the trees and the grasslands, the ferns and mosses, and I did not speak out — because they are just plants. Then they came for me — because we had so damaged the great web of life that everything I depended upon for life was gone.”
Dr. Trevor Hancock is a retired professor and senior scholar at the University of Victoria’s School of Public Health and Social Policy.