One of the coolest things about science is the cross-fertilization that happens between disciplines.
I'm always impressed when I see examples of this, and my reaction is usually, "How did you even think of doing that?" It is, at its core, a highly creative process. The best science involves looking at a problem from a different angle, drawing in data or methods from other disciplines, and putting the whole thing together in such a way that the answer is clear. (Or at least, a piece of it is clearer than it was before.) As Hungarian biochemist Albert von Szent-Györgyi put it, "Discovery consists of seeing what everyone has seen, and thinking what no one has thought."
The creative aspect of science struck me while I was reading an article yesterday in Ars Technica about a some new research into a historical puzzle: the sudden collapse of the Shang Dynasty in China, about three thousand years ago. The Shang were in power for nearly six centuries -- a pretty long time for a single dynastic regime -- and had made some significant accomplishments, the most notable of which were the first recorded writing system for Chinese, and amazing advances in pottery making and bronze casting. Then -- over a very short period, perhaps only a few years -- Shang rule imploded. A rival group called the Zhou took advantage of the chaos to defeat the Shang in a bloody battle, then scattered the remaining Shang supporters throughout the land to assure they'd never be able to rise again.
Now, researchers at Nanjing University, led by meteorologist Ke Ding, have drawn on a variety of disparate fields -- meteorology, climatology, geology, archaeology, paleontology, and analysis of extant historical records -- to try to create a complete picture of the causes behind the Shang Dynasty's sudden demise.
Their conclusion: the collapse of the Shang was the consequence of a long line of dominoes that started with a series of prolonged and powerful El Niño events, thousands of kilometers away.
Paleontologists analyzing fossil remains in strata off the coast of Peru dating to around 1000 B.C.E. note a shift from cold-water species to those that favor warmer water. The fact that there wasn't an oscillation back and forth, but a replacement by warm-water species that lasted perhaps a century, suggests that rather than the usual pendulum swing of El Niño/La Niña conditions -- the former causing a warmup of the surface waters off the west coast of South America, the latter a corresponding cooldown -- in the years before the Shang collapse, the climate seems to have switched over to a semi-permanent El Niño. What would be the outcome of such a shift in the ENSO (El Niño Southern Oscillation)? This is where the meteorologists and climatologists took over; they estimated the degree of warmup, and let their computer models predict what effects that would have.
One thing that popped out of the models was a drastic increase in the strength of Pacific typhoons, and a significant change in their paths. The warmup shifted wind patterns, tracking large storms away from Australia (thus the droughts and wildfires in Australia and Indonesia that usually accompany El Niño years), and northward into China. Typhoons, though, usually fizzle once they cross over from ocean to land; and the capital of the late Shang Dynasty was Zhaoge, in Henan Province, far away from the coast. So how would typhoons have affected an inland city so drastically?
But the models showed that the altered wind direction didn't just shove storms toward China, it also fed warm, moist air inland -- atmospheric rivers. These air currents flow until they meet a mountain range, and the humid air masses experience adiabatic cooling as they rise in elevation, causing them to dump their moisture as rain or snow on the leeward sides of mountains.
In other words, the rain shadow effect. The outcome; suddenly northern and central China were way wetter than they had been.
Now, enter the archaeologists. One of the most common items in Shang-age archaeological sites are oracle bones -- usually the scapulae of ox, horses, or deer that are thrown into a fire, and the resulting cracks and scorch marks read by a shaman. But fortunately for us, the shamans -- recall the Shang's development of the first Chinese writing system -- also recorded on the oracle bones what questions had been asked, and what the shaman's assessment of the results had been (i.e., the answer to the question).
And in the last fifty years of the Shang Dynasty, just about all of the oracle bones have to do with the weather. A lot of them basically ask, "When the hell is it going to stop raining?"
At the same time as this, the archaeologists also note the abandonment of village sites near riverbanks, an increase in burial of sites under riverine sediments, and the relocation of towns onto higher ground.
What Ke Ding and his colleagues concluded is that the Shang were weakened by years of floods, probably accompanied by poor harvests and resulting famine. This set the stage for the Zhou rebellion, and the destruction of a dynasty that had ruled China for six centuries.
Now, here's the kicker. The researchers caution that we're seeing a similar pattern today -- anthropogenic global warming is increasing oceanic surface temperatures, and the Pacific Ocean is seeing extended and more powerful El Niño events. As Mark Twain observed, "History doesn't repeat, but it often rhymes."
Oh, except that noted climate scientist Donald Trump has evaluated the available data, and decided that global warming is a hoax, and the climatologists are big fat poopyheads. So there's that.
Anyhow, it's a fascinating and elegant piece of research, and shows how creative the scientific enterprise can be. Collaboration is the heart of discovery, and here we have an entire team of experts from disparate fields pitching in together to solve a historical puzzle. One that, despite Trump's pronouncements, we had damn well better pay attention to today.
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