The fall of a medium-sized asteroid to Earth will lead to a dramatic climate change on the planet. Temperatures will drop, a new ice age will come, and harvests will be reduced by at least half for several years. Scientists presented such calculations at the annual conference of the American Geophysical Society, and Space.com briefly reports on them.
"Times are not going to be pleasant," said study author Charles Bardeen. After the impact of an asteroid with a diameter of one kilometer on the surface of one of the continents, a 15-kilometer crater will appear. Tons of dust will get into the atmosphere, and the flaring fires will also throw soot into the air.
These particles will remain in the atmosphere for at least six years. Heating up in the sun, they will raise the temperature of the stratosphere. This will accelerate chemical reactions that destroy the ozone layer - it will shrink by 55 percent, and in the tropics, ultraviolet radiation will rise to deadly levels.
At the same time, soot and dust will reduce the amount of sunlight reaching the Earth's surface by 60 to 70 percent. As a result, the average temperature will drop by eight degrees Celsius, like in the most severe ice ages.
A global cooling will also cut rainfall by 50 percent (due to reduced convection). All this will lead to a catastrophic drop in yields, primarily in Europe, North America and northern Asia.
Fortunately for humanity, the likelihood of an asteroid falling to Earth, the impact of which scientists will describe, is very small in the coming decades. None of the 879 known asteroids more than one kilometer in diameter pose a threat to the planet.