As ever, biodiversity is a subject of much worrying misinformation, for a variety of reasons—misunderstandings, faulty statistics, screaming headlines. It turns out that things are not as bad as they are made out to be, and we can fix the most dangerous trends in biodiversity with measures we need to take anyway.
An example of screaming misinformation.
Two generations of humans have killed off more than half the world’s wildlife populations
WaPo, 2018
Versions of this headline pop up every two years when the World Wildlife Fund publishes its big report on the state of the world’s wildlife. All of them misinterpret the numbers.
The metrics we use to measure biodiversity are often tricky to grapple with, and many of us find ourselves tied up in terms that we’ve misinterpreted.
Hannah Ritchie, Not the End of the World
Take the real-life example of two populations of the black rhino: one in Tanzania, and one in Botswana.
Black Rhino Populations
|
1980 |
2017 |
% change |
| Tanzania |
3795 |
160 |
-96 |
| Botswana |
30 |
50 |
+67 |
If you make the mistake of averaging the percentages, as the Living Planet Index does, you get a decrease of 15%, but in reality we lost 3615 out of 3825, which is 95%.
The Living Planet Index tells us that by 2018, on average these numbers have declined by 69% since 1970.
Almost half the populations were increasing, and half were decreasing. To get such a large average decline across all populations, those that are declining must be doing so much faster or at a much bigger magnitude than those that are increasing.
When we look at these countries separately, we see that we need to stop what is failing in Tanzania, and embrace what is working in Botswana.
There has been an 85% decline in wild mammal biomass on land since the rise of humans.
Wild animal biomass is now down to 3 million tonnes of carbon, just 15% of what roamed the planet 100,000 years ago.
By 1900, wild animals made up just 17% of total mammal biomass. Humans made up 23%, and our livestock a whopping 60%.
“The Insect Apocalypse is Here” was a headline in the New York Times that took the world by storm. We now take it as a given that insects are on their way out. But it’s not quite as simple as that.
Insects on land in North America are declining by 2%/year, but freshwater insects are increasing by 1.1%/year, because water quality is improving steadily in many countries.
Overhunting and agriculture have been responsible for over 75% of all plant, amphibian, reptile, bird and mammal extinctions since 1500.
I don’t think we will put as much direct effort into solving biodiversity loss as our other environmental problems. But what makes me optimistic is that we will reduce it indirectly by tackling all of the other problems. A wonderful byproduct of slowing climate change, fixing our food systems, stopping deforestation, ending plastic pollution and protecting our oceans is that we stop piling pressure on the species around us.
- Protect our most biodiverse sites from explaitation
- Increase crop yields to reduce farming land
- Bring deforestation to an end
- Eat less meat, and reduce our need for livestock
- Improve our efficiency of, but don’t eliminate, chemical inputs such a fertilizers and pesticides
- Slow global climate change
- Stop plastic leaking into our oceans
