Sixth Extinction

Researchers found that populations of 71 percent of the butterfly species have decreased over the last 20 years, compared to 56 percent for birds and 28 percent for plants. Two butterfly species (3.4 percent of total) became extinct, compared to six (0.4 percent) of the plant species surveyed … Crucially, the decline in populations happened in all the major ecosystems and was distributed evenly across Britain, rather than in just a few heavily degraded regions.

In the worst case scenario, between a third to a half of land animal and plant species will face extermination. The predictions come from extinction models based on over 1100 species covering a fifth of the Earth’s land mass … Using the mid-range climate predictions, the researchers found that by 2050 between 15 and 37 per cent of the species would be on the “slippery slope” to extinction.

Paleontologists have long puzzled over the mass extinction at the end of the Permian. There is no evidence for a large asteroid impact, but sharp changes in carbon isotope ratios indicate something triggered massive releases of frozen methane hydrates from under the sea floor and in permafrost … Bob Berner of Yale University calculated that a cascade of effects on wetlands and coral reefs would have reduced oxygen levels in the atmosphere from 35 per cent to just 12 per cent in only 20,000 years – a fleeting moment in geological time … Lungs used to higher oxygen levels strain desperately for oxygen, and fill with fluid. The lack of oxygen would have left most Permian land animals gasping for breath, suffering from nausea, headaches, and inflamed lungs. Marine life would have suffocated in the oxygen-poor water.