If you like mass doom you will like this article . Borrowing a theme from the television show Dr. Who, occasionally nature tries to exterminate life on earth, as the Daleks try to do to humans in science fiction.
Over the course of its 4.5-billion-year existence, the Earth has occasionally lashed out against its inhabitants. At five different times, mass extinctions ensued.
Seven hundred million years ago, the oceans’ single-cell organisms started linking together to form multicellular creatures. Four hundred and forty-four million years ago, nearly all of those animals were wiped out by the planet’s first global annihilation. The Earth recovered—fish appeared in the seas, four-legged amphibians crawled onto land—and then, 372 million years ago, another catastrophe destroyed three-quarters of all life. For more than 100 million years after that, creatures thrived. The planet hosted the first reptiles, the first shelled eggs, the first plants with seeds. Forests swarmed with giant dragonflies whose wings stretched two feet across, and crawled with millipedes nearly the length of a car. Then, 252 million years ago, the “Great Dying” began. When it finished, 96 percent of all species had vanished. The survivors went forth and multiplied—until, 201 million years ago, another mass extinction knocked out half of them.
The age of the dinosaurs opened with continents on the move. Landmasses that had spent millions of years knotted together into the supercontinent of Pangaea began to drift apart, and oceans—teeming with sponges, sharks, snails, corals, and crocodiles—flooded into the space between them. It was swimsuit weather most places on land: Even as far north as the 45th parallel, which today roughly marks the U.S.–Canada border, the climate had a humid, subtropical feel. The North Pole, too warm for ice, grew lush with pines, ferns, and palm-type plants. The stegosaurs roamed, then died, and tyrannosaurs took their place. (More time separates stegosaurs from tyrannosaurs—about 67 million years—than tyrannosaurs from humans, which have about 66 million years between them.) It was an era of evolutionary innovation that yielded the first flowering plants, the earliest placental mammals, and the largest land animals that ever lived. Life was good—right up until it wasn’t.
Later, writing about the explosion of an Icelandic volcano called Laki, which wiped out a fifth of Iceland’s population, more gloom ensues:
On June 8, 1783, Iceland’s Laki volcano began to smoke. The ground wrenched open “like an animal tearing apart its prey” and out spilled a “flood of fire,” according to an eyewitness’s diary. Laki let loose clouds of sulfur, fluorine, and hydrofluoric acid, blanketing Europe with the stench of rotten eggs. The sun disappeared behind a haze so thick that at noon it was too dark to read. (Unlike the cone-shaped stratovolcanoes from third-grade science class, both Deccan and Laki were fissure eruptions, which fracture the Earth’s crust, spewing lava as the ground pulls apart.)
Destruction was immediate. Acid rain burned through leaves, blistered unprotected skin, and poisoned plants. People and animals developed deformed joints, softened bones, cracked gums, and strange growths on their bodies—all symptoms of fluorine poisoning. Mass death began eight days after the eruption. More than 60 percent of Iceland’s livestock died within a year, along with more than 20 percent of its human population. And the misery spread. Benjamin Franklin reported a “constant fog” over “a great part of North America.” Severe droughts plagued India, China, and Egypt. Cold temperatures in Japan ushered in what is remembered as the “year without a summer,” and the nation suffered the worst famine in its history. Throughout Europe, crops turned white and withered, and in June, desiccated leaves covered the ground as though it were October. Europe’s famine lasted three years; historians have blamed Laki for the start of the French Revolution.
The article is relevant for a number of reasons. First, it details planetary catastrophes have already occurred, which should sober anyone. Second, it narrates an unresolved battle of words between those who believe that dinosaurs were wiped out by the Chicxulub asteroid and those who think they were wiped out by massive (fantastically massive) volcanic outpourings that produced the basaltic plateau that covers most of India, the Deccan Traps. Third, it lends credence to my idea that a great many scientific disputes operate at any given time. When you hear some idiot say that “the science is settled”, you know you are hearing a political statement. The science is never settled. It is only provisionally accepted in some quarters for some people, for some time.