Exploring the Impacts of El Niño

Perspectives | Dec 31, 2016

by Andrew Pershing, Ph.D.

Adjunct Scientist & Former Chief Scientific Officer

Early last year, everybody wanted to know about El Niño. What is it? How does it affect ocean temperatures? With these questions swirling, Chief Scientific Officer Andy Pershing jumped on the opportunity to explain El Niño and how it affects us in the Gulf of Maine.

Chief Scientific Officer Andy Pershing poses outside in the sunlight for a portrait in front of a marina, wearing a blue vest with Gulf of Maine Research Institute written on the upper left.
Chief Scientific Officer Andy Pershing

Greetings from February 18, 2016! This week, we went from the coldest temperatures of the year on Valentine’s Day to windy, wet, and (relatively) warm conditions a few days later. After experiencing these extremes, wacky even by New England standards, it requires a bit of courage to predict that water temperatures will be warm this spring — yet, that’s exactly what we and other climate scientists anticipate.

So far, this has been one of the mildest winters ever in New England. December was 11.4°F above normal, making it the warmest December in Maine by almost 5°. January was 6.1°F above normal — warm, but not quite record-setting. NOAA’s Climate Prediction Center is forecasting that mild conditions will prevail into the spring.

You can blame these unusually mild conditions on the Pacific Ocean. Normally, the trade winds that blow from east-to-west along the equator create a blob of very warm water in the western Pacific, near Indonesia. These same winds pull cold water to the surface in the east, leading to cold conditions off of Ecuador. If the trade winds get weaker, the warm water sloshes to the east.

The appearance of warmer-than-normal water off of Ecuador is the hallmark of the phenomenon known as El Niño. Under such conditions, global weather patterns go haywire.

The impacts of El Niño are dramatic, but they aren’t random. Conditions in an El Niño year are incredibly predictable, and El Niño effects reach far beyond the warm waters of the Pacific. The warm water sloshing across the Pacific during El Niño changes the flow of heat and moisture across the globe.  For us, it means that we get warm, moist air from the south — almost the exact opposite of the conditions we experienced last February. You can learn more about El Niño and what it means for the Northeast at http://www.nrcc.cornell.edu/services/special/special.html.

It is important to note that El Niño is not the only part of the story.  Each year, the Earth gets a little bit warmer as our temperature adjusts to the extra carbon dioxide we’ve put in the atmosphere.  This means that the conditions this winter are warm, even when compared to other El Niño years.

Right now, the water temperatures at the three NERACOOS buoys along the coast of Maine are running about 2°F above average at both the surface and 165 feet below.  This is quite warm, but it’s down from the record temperatures we were at before the Valentine’s Day cold snap.

Although we’re not quite at record levels, the warm temperatures and mild weather are reminiscent of 2012. That year, the Gulf of Maine was at the epicenter of a large scale “ocean heatwave.”

We know warming waters affect commercially and economically important species in the Gulf of Maine. For example, the warm water caused the lobster fishery to shift into its summer, high-landings mode 3–4 weeks early in 2012. That experience caused us to launch our lobster forecasting effort, which attempts to predict the annual landings spike based on water temperatures.

Forecasting and other climate adaptation efforts continue to be an important piece of our work here in the lab. As waters warm, we’ll learn more about the associated impacts on species such as lobster, cod, shrimp, and herring. We hope the lessons learned from this research will give fishing communities throughout the bioregion the information they need to sustain their way of life.

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