Only 200 years ago did humans begin to systematically categorize the species, and within that relatively small stretch, we’ve recorded about 2 million species of plants, animals, fungi. But that’s only the tip of the iceberg. By some estimates, we still have another 2 million to uncover, and by others, there are upwards of 100 million left to be classified. However, with deforestation, sprawl, and, above all, climate change putting the planet in jeopardy, scientists believe millions of species will die off before we will even encounter them. And the implications of this are far-reaching.
For several decades, scientists have warned that we are headed into, or may even be experiencing, the sixth mass extinction. As The Guardian notes, there have been five other instances like this in the past, including the end-Cretaceous extinction, which led to the demise of the dinosaurs 66 million years ago. However, to know for certain if we’re amidst doom and gloom, scientists need to determine the rate at which species are disappearing, and when human activity is factored in, how by how much this rate increases.
Previous studies have deemed humans to indeed be major drivers, possibly causing animal species to go extinct “up to 100 times” faster because of human activity, as one team of American and Mexican scientists found. However, Terry Erwin, a world-renowned tropical entomologist, says that the data that has historically been used in these studies is wholly incomplete and “biased towards a very small portion of biodiversity.” Rather, if scientists want an accurate picture of existing conditions, they need to look beyond vertebrates to invertebrates like worms, snails, spiders, octopuses, and most importantly insects, which account for about 70 percent of the Earth’s living creatures. Indeed, only one in 200 of all known species is a mammal. With that said, to determine the true rate of extinction of species on Earth, you need to determine the scale of the insect kingdom—and this is the biggest challenge.
While the scope of the insect population is still being explored, The Guardian does cite a “breakthrough” that’s offered some insight into what we’re dealing with. In 1982, Erwin headed to a rainforest in Panama with the goal of determining how many species of insect lived on average across one acre of forest. He chose one tree, which he draped in sheeting and used blasts of insecticide to fog the bugs out. Over several hours, as the insects evacuated the tree onto the sheeting, Erwin was able to collect 1,200 species of bugs, of which he later determined more than 100 of which were exclusive to that one tree. From those findings, he averaged that there are about 41,000 different species per hectare of rainforest, and in turn 30 million species worldwide. The estimates, however, he now deems conservative and suspects the number could actually be between 80 and 200 million, but adds that tens of thousands of them are probably disappearing annually without us even knowing.
Of no surprise, climate change is being pinned as the fundamental driver of the great insect die off. Scientists have even noticed drops in the virgin forests of Ecuador and places where insecticides aren’t being used and humans have not cut down a single tree. As the Guardian writes, based on data collected, Erwin and his collaborators have found that the Amazon rainforest has been slowly dying out over the last 35 years. “[If the forest goes out] everything that lives in it will be affected,” he told the site.
The disappearance of insect life on Earth would surely mean the end of all life on Earth. Insects are responsible for the planet’s course of evolution from flowering plants to food chains and are key to keeping those systems functioning. As EO Wilson, a celebrated Harvard entomologist, and inventor of sociobiology, tells The Guardian, humanity would last all of a few months without insects and other land-based arthropods. “After that, most of the amphibians, reptiles, birds and mammals would go, along with the flowering plants. The planet would become an immense compost heap, covered in shoals of carcasses and dead trees that refused to rot. Briefly, fungi would bloom in untold numbers. Then, they too would die off. The Earth would revert to what it was like in the Silurian period, 440m years ago, when life was just beginning to colonise the soil – a spongy, silent place, filled with mosses and liverworts, waiting for the first shrimp brave enough to try its luck on land.”
Via The Guardian
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