We don’t really know the total number of species on Earth, let alone how many species are already extinct. Only a fraction of the Earth’s animal and plant species are known. Among better known vertebrate animal species, scientists conclude that at least 338 species have gone extinct and 617 vertebrate species are now “extinct in the wild” or “possibly extinct.” But 99 percent of the Earth’s animal species are invertebrates, and their survival is in even greater jeopardy. The International Union for Conservation of Nature (IUCN) counts 26,500 species threatened with extinction: 40 percent of amphibian species, 25 percent of mammals, 14 percent of birds, and worse for marine species on the verge of extinction. Recent studies indicate that a third of the Earth’s insects are endangered, with the total numbers of insects dropping by about 2.5 percent EVERY YEAR.
Mass extinction is underway. Scientists define mass extinction as an epoch of time when at least 75 percent of all species vanish from our planet. The previous five mass extinctions occurred over the past 450 million years, with the last one happening when a massive asteroid hit the Earth and wiped out dinosaurs and most other living species, about 66 million years ago.
Now we humans are the principal culprit causing the current and sixth mass extinction of life on our planet. Current extinction rates have climbed to somewhere between 100 to 10,000 times faster than Mother Nature’s regular pace of species evolution and extinction.
The negative consequences are enormous. Extensive loss of species can have catastrophic effects on the food chain, on ecosystems’ support systems, on pollination of plants (including our food crops). “This is far more than just being about losing the wonders of nature, desperately sad though that is,” says WWF’s Barret. “This [mass extinction] is actually now jeopardizing the future of people. Nature is not ‘nice to have’—it is our life-support system.” --Chuck Roes, SCP President