Note: This post is relevant
A recent report has garnered some attention for its declaration that we have entered Earth’s sixth Mass Extinction – the first since the disappearance of the dinosaurs. They also state that humans, as a species are at risk of going extinct.
I’ve got lots to say about all this, but right now I want to address how we know what we know.
Most people not involved in the study of plant and animal populations don’t have a very clear idea of how scientists come to conclusions like this. There’s no reason they SHOULD, but having an idea of how we know what we know can act as a defense against those who say things like this are all made up.
When I was in college, I spent one week on some islands in the Bahamas (terrible, I know), studying a population of iguanas. I was part of a group of around 10 people led by a biologist who had been doing this for 20 years. This species only lives on three islands, and was almost extinct when he started studying them.
20 years later, with the help of the Bahamian government, they were doing quite well, and he had a massive amount of information about the iguanas, how long they lived, how many there were, what their breeding habits were, and so on.
This was achieved by spending between two weeks and a month on the islands about once a year.
This same biologist was doing similar studies of turtles in a couple places in Indiana, Nebraska, and probably a couple other places I’m not remembering.
I also spent time in Tanzania, and talked to biologists there who were studying everything from plants to elephants.
I also talked to scientists at the New England Aquarium that monitor fish and sea turtles populations all along the East Coast of the United States.
When I worked for a state department of natural resources, I spent two summers doing similar work to what I had done with the iguanas and turtles, this time with snakes. There were fewer of us studying many more populations, so it took us a full summer to cover about half the significant habitats in the state.
I also did some filing work for that department, going through the records of citizens reporting in about animals they had seen.
Now I regularly interact with people who are doing the same thing with bird species – counting them, weighing them, and monitoring how their populations have been changing for the last 50 years.
I’ve also been talking to people who’ve collected plant and bird records from scientists and hobbyists going back in to the 1800s.
This is just the tangential experience of one person, who studied biology as an undergrad in one college, and worked for a couple science-related organizations afterwards.
In the U.S. alone, there are thousands of colleges and universities that do similar kinds of research at different levels. Every state has an agency that ALSO hires scientists to do research. Every state also has people who closely monitor wildlife for their own reasons – hunters, birdwatchers, reptile enthusiasts, frog enthusiasts, fishermen, and so on.
Many of the colleges I mentioned ALSO do research in other countries all over the world, but all of those countries also have their own researchers and institutions doing their own work.
This work involves individually counting lizards, or snakes, or turtles, or birds, insects, or fish, or mammals, or plants, or sometimes number of flowers ON plants.
On every continent, in every country, in every habitat in all conditions of all seasons, there are thousands of people constantly monitoring the myriad of organisms we share our planet with – and in some cases rely on.
All of these people also share their data, and publish it, and cross-check it, and add it in to common databases that cross international boundaries. All of this work goes back generations, and as the human population has grown, so to has the number of people studying the world we live in, as well as our capacity to do so.
That is how we know that species are going extinct. That is how we know that the climate is changing – because for every person I mentioned who’s studying life on earth, there’s also someone studying the planet’s past, and someone studying the chemical composition of the atmosphere, and someone studying how those chemicals behave in different conditions.
The entire planet is changing all around us, and everybody who’s watching can see it.