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These rings have also shown that for six decades, from 1568 to 1634, due to natural variation in climate, there had been six decades of expansion of the subtropical zones, which pushed desert climates towards the north. Due to the expansion of hot and dry weather areas, the Ottoman Empire in Turkey has ended, the Ming Dynasty has collapsed and the Jamestown Colony in Virginia has been abandoned, suggesting, he added, that they are partly at least climate-related. "The way society handles drought politically is also part of the picture," she said.
Other sources – lake sediments; samples of ice cores; coral; otoliths or bones of fish ears; and even the shells of live and dead geoducks, a large bivalve with a serpent-shaped appendage – add to the overview.
"We have divers sucking old coolers from the bottom of the ocean," said Bryan Black, professor of dendrochronology also specializing in marine life. Combined with long dead geoduck hulls, the data can go back thousands of years. The shells of the Icelandic coast date back 1,000 years ago. "They show that the last century has been unprecedented hot," said Dr. Black.
Experts use information on shell rings, associated with the ringside data, to understand how climate conditions ocean productivity and mixing fish species, to help fisheries managers . "The bottom line is to be aware of climate lash and what it means for fishing, "said Dr. Black.
Even the stars entrust some of their secrets to the trees. The sun and others stars emit radiation called galactic cosmic rays, or G.C.R.s, which react in the atmosphere with nitrogen and alter the levels of carbon 14, which is absorbed by any living being and becomes a tracer of cosmic ray levels.
Past peaks of G.C.R.s caused by solar flares or other sources are largely a mystery, but arouse keen interest from researchers as they could destroy communication satellites and other technologies. An event in 744, first discovered in the cedars of Japan and since then throughout the world, is the most powerful event of the cosmic ray of the disc, a magnitude greater than that of the event. Carrington, a solar storm of 1859, and apparently reported by times.
"This year also appeared in the heavens a red crucifix, after sunset," commented the Anglo-Saxon Chronicles newspaper that recounted the event in the mid-eighth century.
It was very likely a huge solar flare. "It's an unprecedented experience, there is nothing else," said Charlotte Pearson, a professor at the lab. "We try to work what it is and what caused it but we are still not sure. "
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