Sheesh, I was just going to go to bed, but then this had to come out.
The Guardian just picked up a new study today from the Elsevier journal Biological Conservation by researchers at the University of Sydney and the University of Queensland (Brisbane) that has some pretty unsettling conclusions:
The world’s insects are hurtling down the path to extinction, threatening a “catastrophic collapse of nature’s ecosystems”, according to the first global scientific review.
More than 40% of insect species are declining and a third are endangered, the analysis found. The rate of extinction is eight times faster than that of mammals, birds and reptiles. The total mass of insects is falling by a precipitous 2.5% a year, according to the best data available, suggesting they could vanish within a century.
Dropping by 2.5% a year means they’ll be gone in a century? Really? Let’s graph that out:
Aw, crap.
Insect population collapses have recently been reported in Germany and Puerto Rico, but the review strongly indicates the crisis is global. The researchers set out their conclusions in unusually forceful terms for a peer-reviewed scientific paper: “The [insect] trends confirm that the sixth major extinction event is profoundly impacting [on] life forms on our planet.
“Unless we change our ways of producing food, insects as a whole will go down the path of extinction in a few decades,” they write. “The repercussions this will have for the planet’s ecosystems are catastrophic to say the least.”
Briefly, those links tell you that in Puerto Rico, rainforest insects over the last 35 years have lost 98% of their population on the ground and 80% in the canopy. In Germany, nature reserves have seen a 75% drop in flying insects over the last 25 years. So the researchers cited here are NOT the only ones saying things like this. In fact, their paper is a compilation of the 73 best studies they could find. The figures they give aren’t alarmist; they’re a collection of real data.
The main causes, directly from the paper:
The main drivers of species declines appear to be in order of importance: i) habitat loss and conversion to intensive agriculture and urbanisation; ii) pollution, mainly that by synthetic pesticides and fertilisers; iii) biological factors, including pathogens and introduced species; and iv) climate change.
Time for an extremely quick review of why we depend on insects so much:
They maintain soil structure and fertility, pollinate plants and control insect and plant pests. Many insects feed on dead animals and fallen trees, thereby recycling nutrients back into the soil.
Various insects are also a common food source for larger animals. “If this food source is taken away, all these animals starve to death,” Dr Sánchez-Bayo said.
And another:
There are more than a million species of insect, compared with just 5,400 mammals, and they are the cornerstone of all terrestrial ecosystems. Without them, you get what scientists call a “bottom-up trophic cascade”, in which the knock-on effects of the insect collapse surge up through the food chain, wiping out higher animals. And without healthy ecosystems, there is no clean air and water.
Note the common thread there. I’m sorry to plant this one on you. I’m no ecologist or entomologist, but this struck me a lot differently from hearing about sea level rises in 1000 years and how awful that will be. Will we even be around to notice that? Not if we don’t start figuring this insect extinction problem out very soon.
----—
A bit of an update: There are some commenters who correctly point out that we cannot say for certain that insects will disappear entirely, and I agree with them on that, of course. It is an extrapolation, and things like that seldom continue unabated. However, the practical effect on humans could be in the same league, and I thought it was OK to err on the side of hyperbole here to illustrate the seriousness of the issue. Insects ARE on pace to be extinct within 100 years, and the slope of that line is a very big problem. You see in the examples that there are indeed local collapses that have followed an even-faster trajectory. I don’t think you can alter insect populations this radically, this quickly, and expect things to turn out all right.