"Sonny Whitelaw - Rgesus Factor" - читать интересную книгу автора (Whitelaw Sonny)

is clear and irrefutable: in the composition of the soil and the shape of the land, in tree rings and Arctic ice
cores, and after mankind arrived, in archaeological digs.

'At the end of the last great Pleistocene ice-age, Earth's climate began another of its periodic adjustments.
In less than ten years global temperatures jumped more than five degrees Centigrade. Glaciers melted,
the seas and rivers rose, inundating previously dry lands. And it rained. Not just everyday rain, but a
deluge so great that climatologists called this period a fluvial.

'Then something extraordinary happened; a perverse side effect of global warming. The Gulf Stream shut
down, and in Europe and North America the warming cycle went into full reverse. The air cooled and the
glaciers returned as rapidly as they had retreated. Areas that had thrived under the warmer postglacial
regime suddenly became inhospitable, driving species to extinction and devastating the lives of the cave
dwelling humans that depended on them.

'But humanity had reached a watershed moment. Having enjoyed the relatively short benefits of warm
weather, this new adversity birthed a human invention that would revolutionize the world: agriculture. It
was a coping strategy, the first attempt by Homo sapiens to impose order on the environment instead of
succumbing to it.

'The first feeble attempts at agriculture stumbled along for almost nine millennia. Then the world's climate
seesawed again. The Gulf Stream returned, Europe and North America warmed and the glaciers
receded. And this time, they did not return.

'As the ice melted and the temperatures soared, rain again inundated the world. Stories of vast floods
abound in cultures from China and the Americas to the Middle EastтАФalthough it seems only Noah
decided to tough it out instead of heading for high ground.

'In the fertile crescent between the Tigris and Euphrates rivers, floods might have drowned the hapless
nomads and animals that missed Noah's Ark, but they were also a sign that spring had arrived to a planet
too long wrapped in winter. From this veritable Garden of Eden, mankind went forth and multiplied,
taking agriculture to Africa, Asia and the Americas. City-statesтАФthe precursors of modern
civilizationтАФwere born.

'For the next five millennia civilization marched inexorably across the globe. In the fifteenth century
Europeans crossed the Atlantic, supplanted the prior inhabitants and claimed the Americas. It was
serendipity that for the next four hundred years Europe and North America were blessed with some of
the finest weather in millennia.

'Few appreciated that these halcyon years were a direct result of climate. And almost certainly no one, at
least not until the twentieth century, understood that this climate was regulated by the flow of the Gulf
Stream.

'The mechanism is simple enough. When seawater freezes, it leaves behind salt. This causes the remaining
water to become dense and heavy, so it drops to the ocean floor. Each winter, above the Arctic Circle,
the seawater freezes into an ice pack covering hundreds of thousands of square kilometres. And it
produces huge volumes of dense, heavy water. With plenty of momentum and nowhere to go but south,
the water falls to the Atlantic seabed then flows past Europe and Africa. As it crosses the equator it
begins to rise, picking up nutrients and heat. In the South Atlantic it curves west before turning north then
crossing the equator again and flowing into the Gulf of Mexico. Finally, a few years after leaving the
Arctic, the water resurfaces near North America as the warm Gulf Stream.