快猫短视频

BAD weather may have triggered the fall of the Roman Empire. When the
Visigoths and other northern barbarians upped sticks and headed south into Roman
territory in the 5th century it might have been to escape the cold and poor
harvests.

Waning sunspot activity is a symptom of a weakened Sun, which could make the
world cool by around half a degree. Meteorologist Kevin Pang found that sunspots
were conspicuously absent from the historical record. 鈥淭hat was just about the
time the Roman Empire fell in 476,鈥� he says. The gaps in sunspot sightings
coincided with high levels of carbon-14 in tree rings鈥攁nother indicator of
fainter solar activity鈥攈e told the American Geophysical Union last
week.

Pang thinks the resulting change in climate could have indirectly caused the
end of the Romans鈥� dominance in Europe. 鈥淚n the northern latitudes, a half a
degree of cooling can shorten the growing season just enough to make crops
fail,鈥� he says. That might have sent the barbarians south into the Roman
Empire.

And it might have been even colder according to another study published
earlier this month (Science, vol 294, p 2149). Researchers at Goddard
Space Flight Center in Maryland developed a computer model of the effects of a
weakened Sun, and found that while global temperatures would only drop by half a
degree, regional cooling would be greater鈥攑erhaps by two degrees in Europe
during the winter.

Earth scientist Michael Rampino of New York University says the idea is
plausible. 鈥淚f the climate is changing, it鈥檚 certainly enough to affect what is
going on in the world of cultures at the same time.鈥�