A newly released study co-authored by a UC Santa Barbara researcher shows El Niños have been growing more intense in recent years.
"The amount of variability (and) the overall strength of El Niño and La Niña events over the past 50 years is larger than at any time over the last thousand years," said Sam Stevenson, Assistant Professor at UC Santa Barbara's Bren School of Environmental Science and Management.
The study is based on an examination of coral in the Galapagos Islands. Stevenson likened it to tree ring research, where the rings tell scientists about the climate conditions as the tree grew.
"The same thing is true for corals," she explained. "They also grow in response to the ocean conditions around them. You can drill into a coral like you would a tree ring, and see the layer of growth that happens over the course of a year. That's a function of the temperature near the coral...what we're measuring is the heavy to light oxygen in the calcium carbonate that makes up the coral."
Stevenson is one of a dozen researchers from around the world working on the project. The lead author of the research is Julia Cole with the University of Michigan's Department of Earth and Environmental Science.
Stevenson said they sampled cores from 13 coral colonies, some ancient and some still alive. They serve as a barometer of what's happening in the ocean.
"They're like little histories of the ocean conditions that were happening around the coral when it grew. They're in the tropics, so they are exactly where El Niños happen, right in the center of the action."
Researchers believe the study provides yet more evidence of the impacts of global warming.
