Tree Rings Say Violent Storms to Continue

Scientists studying ancient tree rings are assembling important benchmark data for studying effects of El Niño and La Niña worldwide, already concluding that our current era ~ because of its warming trends ~ will continue to witness extreme storms.

Due to Earth’s current phase of global warming, which is causing temperatures in the tropical Pacific to rise, the world might see “enhanced El Niño Southern Oscillation variability ~ more severe El Niños and La Niñas, and more extreme climate conditions around the globe,” according to researcher Jinbao Li of the University of Hawaii.

According to LiveScience.com:

The tree rings reveal that over the centuries, the intensity of this climate pattern has been highly variable, with decades of strong El Niño and La Niña events and decades of little activity. The least variability happened during the Medieval Climate Anomaly in the 11th century, whereas the highest variability occurred between the 18th and 20th centuries. 

Many of the El Niño and La Niña events of the last millennium were more intense than the ones scientists have direct data on. Overall, the world has seen a trend of increasing swings to extremes over the past millennium, researchers said. 

These changes in the intensity appear to be linked to the tropical Pacific climate. Samples from lake sediments in the Galapagos Islands, the northern Yucatan in Mexico and the Pacific Northwest suggest that the eastern-central tropical Pacific climate swings between warm and cool phases, each lasting from 50 to 90 years. During warm phases, El Niño and La Niña events were more intense than usual, and during cool ones, they deviated little from the long-term average.

The international team of scientists has peered back into the history of this climate pattern by analyzing trees up to 1,100 years old. Periods of El Niño result in wider tree rings, and periods of La Niña in narrow ones.

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