El Niño may have more to do with climate change than previously thought, new research shows. El Nino is a rise of water temperature off the coast of Eastern South America that often spurs catastrophic climate effects.

About every seven years, El Niño sends a deluge of rainfall to Eastern South America, turning much of the continent to mud. Floods and typhoons are rampant. Yet other parts of the countries get no rainfall and experience drought. Fish die; the birds that eat them die; people die due to lack of clean drinking water. This has severe and widespread economical effects on these countries.

But El Niño is difficult to track. It's normally about every seven years, but it's often come every two or three. And new research suggests that El Niño does have to do with global warming.

Scientists previously thought that El Niño was an isolated climactic phenomenon that has always existed-simply a series of short-term fluxes in weather rather than attributable to global warming, a long-term phenomena.

But El Niño has been unusually active in the last fifty years as compared to the entirety of the last seven centuries. This therefore suggests that El Niño is responsive to climate change, and that scientists may be able to better predict it in the future.

The new research takes El Niño from the context of a short-term fluctuation to a long-term cycle. When the phenomenon is looked at longitudinally, a clear pattern emerges.

Researchers used over 222 tree-ring chronologies of the past seven centuries. The trees were compiled from both the mid-latitudes in both hemispheres and the tropics. It seems El Niño may be moving in tandem with global warming.

Tree rings gave the scientists a robust, accurate record about precipitation, wind, and temperature conditions. They found that El Niño dovetailed perfectly with global warming patterns that have emerged during this century.

"This suggests that many models underestimate the sensitivity to radiative perturbations in greenhouse gases," said Shang-Ping Xie, co-author of the study. She is a  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," she added.

The study will be published in the journal Nature Climate Change.