First published on the Earth Institute website on May 26, 2011.
Bristlecone trees, such as this over 1,000-year-old tree in the Great Basin National Park, contributed to the tree ring record on El Niño. Photo courtesy Gisela Speidel, IPRC
El Niño and La Niña, the periodic shifts in Pacific Ocean temperatures, affect weather around the globe, and many scientists have speculated that a warming planet will make those fluctuations more volatile, bringing more intense drought or extreme rainfall to various regions.
Now, scientists have used tree-ring data from the American Southwest to reconstruct a 1,100-year history of the cycle that backs up that assertion. The researchers found a 50-90-year cycle of waxing and waning El Niño intensity that shows that, when the earth warms, the climate acts up.
“Our work revealed that the towering trees on the mountain slopes of the U.S. Southwest and the colorful corals in the tropical Pacific both listen to the music of El Niño, which shows its signature in their yearly growth rings,” explains Jinbao Li, the paper’s lead author and a former PhD student at Lamont-Doherty Earth Observatory.
The research, published May 6 in Nature Climate Change, will improve scientists’ ability to predict future climate and the effects of global warming, the scientists say.
D.K. Funkhouser 