31 May 2023
The decline of life
When I got my first car, quite a few years ago, one of the first products I bought was bug remover. From spring through summer the windshield and front of the car were pasted with dozens if not hundreds of dead insects after a drive. Now, the most I see is a handful of insect splashes on the front of the car. It’s a visible symbol of the decline of life on our planet. In a recent article the academic journal Biological Reviews published an article trying to put some numbers on the crisis in life on Earth. “The global-scale decline of animal biodiversity … represents one of the most alarming consequences of human impacts on the planet,” write the authors. They looked at population trend data for more than 71,000 species of mammals, birds, reptiles, amphibians fishes and insects. They found that 48 per cent of species were in decline, mostly in tropical regions. The major cause of decline is loss of habitat as wildlands are cleared to cut timber and create more farms and ranches.
“Animal populations and whole species are declining across the tree of life,” they write describing it as the “defaunation” of the planet. The loss of biodiversity is so high they say that life on Earth is entering its sixth mass extinction. The great extinction was 65 million years ago when a huge asteroid plowed into our planet and wiped out about half of plant and animal species at the time, including the dinosaurs.
Scientists have long warned that as the web of life shrinks we start losing ecological or natural services that make our planet habitable. These include maintenance of our atmosphere and water supplies, pollination of many foods and knowledge that leads to development of medicines.