Scientists may have discovered a link between the phenomenon of El Niño - a rise in warm ocean water temperatures that develops every several years off the coast of South America - and the prediction of climate change as a result of global warming, the Christian Science Monitor reports.
About every seven years, coastal Ecuador is flooded and Peru experiences massive typhoons while other parts of South America get little to no rainfall, much of the continent withering in widespread drought. During these times, the economies of coastal nations in South America buckle under pressure as farmers struggle to produce crops and birds and fish populations dwindle.
New research, published in Nature Climate Change, suggests that El Niño is more responsive to climate change than previously believed, and that the phenomenon was uncharacteristically active in the late 20th century in comparison to the last seven centuries. To determine these findings, scientists compiled 2,222 tree-ring chronologies of the past seven centuries from both the mid-latitudes in both hemispheres and the tropics.
Decoding tree rings, a dating method known as Dendrochronology, is often used to gain an accurate history of climate patterns. By reading the tree rings' width and color combinations from each year, scientists can use such patterns to determine the precipitation, wind, and temperature conditions at the time at which the tree was growing. Scientists found that 20th century tree ring patterns suggested that El Nino was more active then than in the last seven centuries, suggesting that El Nino followed in the wake of global warming patterns that were a trademark of that century.
"This suggests that many models underestimate the sensitivity to radiative perturbations in greenhouse gases," said Shang-Ping Xie, co-author and meteorology professor at the International Pacific Research Center. "Our results now provide a guide to improve the accuracy of climate models and their projections of future ENSO activity.If this trend of increasing ENSO activity continues, we expect to see more weather extremes such as floods and droughts."
El Niño is difficult to predict and track, and is unpredictable in when it may depart, be it a year or two years after it occurs.
