Because Arctic regions show such strong seasonality, according to Jason Briner, assistant professor of geology in the College of Arts and Sciences at the University at Buffalo, it is relatively easy to correlate climate changes with very fine layers in the sediments, according to an article in Mongabay.
In some lakes, each layer represents one year, with thicker sediment layers generally signaling warmer summers. Like other paleoclimatologists, he also is finding that the warming trend that began in the 20th century is more pronounced in the Arctic than it is in the rest of the globe.
"The magnitude of warmth over the past 100 years seems pretty exceptional in the context of the past 1,000 years," he said. "Whereas maybe an average of all of the instrument data from the globe shows just a half a degree increase in this century, in the Arctic, temperatures went up by two to three degrees in the same period." The rapidity of the change also is exceptional, he added. "If we look at the temperature graphs that we've generated for the past 1,000 years for this region, the temperatures wiggle back and forth, so there is a little variability in there," he said. "However, in the past 100 years, both the magnitude and the rate of temperature increase exceed all the variations of the past 1,000 years."
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