El Nino Helps Push 2015 Toward Planet's Warmest Year on Record

A Brief History of Global Warming
  • `What we are seeing is definitely a signal of climate change'
  • Temperature needs to reverse trend to keep 2015 from a record

El Nino is the Earth’s hot, exhaling breath.

At least, that’s one way of thinking about it.

The blast of heat from deep within the Pacific Ocean will do more in 2015 than just disrupt weather worldwide. It will push the Earth to another record for heat, said Kevin Trenberth, senior scientist at the National Center for Atmospheric Research in Boulder, Colorado.

“This year is already going to stand out well above anything we have ever seen before,” Trenberth said in a presentation Wednesday at the International Research Institute for Climate and Society at Columbia University’s Lamont campus in Palisades, New York. A record was set last year without a full-fledged El Nino.

Figures released by the National Centers for Environmental Information this week show that through October, the Earth has set temperature records on land, in the oceans and for the combination of the two. The month was the warmest October in records going back to 1880.

Land-Sea Warming
Land-Sea Warming

The upward swing of monthly temperatures over the long term means only one thing to Ahira Sanchez-Lugo, a scientist at the centers in Asheville, North Carolina.

“What we are seeing here is definitely a signal of climate change,” she said in a conference call with reporters Thursday.

With only two months to go, the only way the Earth can avoid setting a record is for November and December to have average temperatures below the 20th century average, Sanchez-Lugo said.

The last time a month was cool enough to dip below the average was February 1985.

“I don’t think we will be experiencing that any time soon,” Sanchez-Lugo said.

El Nino will ensure that doesn’t happen.

Trenberth said the world’s temperature peaks after a section of the equatorial Pacific, called Nino 3.4, hits its high. Nino 3.4 is located along the equator roughly south of Hawaii, and is the area used by the U.S. to rank the strength of an El Nino phenomenon.

Peak Coming

The peak of the current Pacific warming will probably occur as 2015 turns into 2016, the U.S. Climate Prediction Center said. That means there’s probably more heat coming for November and December.

Trenberth said heat like that now being released from the ocean is absorbed during La Nina events, when the equatorial Pacific cools. It is sort of the opposite of El Nino.

A La Nina that occurred in 2010 faded in the first half of 2011. It then returned at the end of 2011 and lasted into 2012.

“In La Nina, there is a buildup of heat in the ocean and El Nino gets rid of the heat,” Trenberth said. “In that sense, it serves as part of the climate system by acting as a regulator of temperature.”

The heat released by El Nino “rolls around in the atmosphere” until it radiates into space, he said.

Then the process starts all over again.

The heat records tend to come with El Ninos because that’s when the ocean releases its warmth. In 2014, the ocean got hotter; however, there wasn’t the necessary reaction from the atmosphere for scientists to declare it an El Nino year.

In the end, the cycle makes the upward trend in global temperatures resemble stair steps, Trenberth said.

There is no doubt, though, those stairs are going up.

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