A wimpy La Ni単a is on the way toward La Nada status

By Tom Yulsman | January 14, 2017 3:48 pm

La Ni単a typically coolsthe Pacific. But this time, large swathes of warmer-than-average sea temperatures have muted the cooling.

Wimpy La Ni単a

A comparison ofsea surface temperature anomalies in the Pacific Ocean for two seven-day periods: Dec. 28, 1998 to Jan. 3, 1999; and Dec. 26, 2016 to Jan. 1, 2017. Thestrong La Ni単a of 1998/1999 is characterized by widespread blue colors concentrated especially along the equator west of South America.Whereas today’s Pacific is far warmer, with a wimpy La Ni単a characterized by only mildly cool temperatures along the equator. (Images: NOAA. Animation: Tom Yulsman)

The surface waters of the Pacific Ocean have been considerably warmer than average lately with one exception: asmall spear of coolness along the equator that’s characteristicof La Ni単a.

Apparently, all that warmth has prevented the currentLa Ni単a a cool phase in the Pacific that influences weather worldwide from gaining much strength. In fact, as La Ni単a’s go, this one has indeed been wimpy ever since it got going in late summer last year.

And now it is almost certainly on the way out, according to the latest analysis by NOAA’s Climate Prediction Center.

The forecast is for La Ni単a tofully dissipate by February, and for neutral conditions neither La Ni単a nor its warm opposite, El Ni単o to remain inplace through the first half of the year. (There are some hints that after that a new El Ni単o could blossom, but it is way too soon to say.)

Our current wimpy and fadingLa Ni単a has been starkly different from a much stronger one that occurred in 1998 and 1999. You can see just how different they’ve been by watching the animation above. It depicts how sea surface temperatures varied from average in late December and early January during both episodes.

The 1998/1999 event followed a monster El Ni単o just as our current La Ni単a did. As 1998 gave way to 1999, sea surface temperatures through much of the Pacific were much cooler than average, as indicated by the large swaths of blue color. And the chill was particularly concentrated along the equator west of South America, a characteristic that helps defineLa Ni単a. (The opposite happens during an El Ni単o warmth along the equator in the eastern and central Pacific.)

Zoom forward in time to the seven-day period between Dec. 28, 2016 and Jan. 1, 2017. The sea of orange and red colors that has spread across much of the Pacific is indicative of much warmer than average ocean surface temperatures. And there’s just a wimpy little area of blue along the equator brought to you by La Ni単a.

Why such a difference?

Last years Ni単o was huge in area, duration, and magnitude, saysBill Patzert, a climatologist at NASAs Jet Propulsion Laboratory, quoted in an Earth Observatory story. My take is that because it lasted so long and covered such a large area, it damped the return of strong trade winds needed for a healthy Ni単a.”

But theLa Ni単a of 1998/1999 was also preceded by a large El Ni単o. So it’s possible that there is more going on as well.

Another phenomenon known as the Pacific Decadal Oscillation, or PDO, couldbe playing a role. Like El Ni単o and La Ni単a, PDO is characterized by a pattern of sea surface temperatures in thePacific Ocean. And it has been in a warm, positive phase since 2014.

In the Earth Observatory story,Mike McPhaden of the NOAA Pacific Marine Environmental Laboratory, had these observations about the possible impact of the PDO:

The climate system is very complex, and many processes are at work at any given point in time and space. It could be just the randomness of the climate system that kept this La Ni単a from taking full flight. Or maybe it is the fact that the Pacific Decadal Oscillation has been in a mostly warm state since 2014, with elevated temperatures in the tropical Pacific making it harder to develop cold anomalies there.

In the animation I created for the top of this post, I’m struck by just how much warmer the Pacific Ocean is today than it was during the same season in 1998/1999. That got me thinking about the big picture.

El Ni単o and La Ni単a two sides of theEl Ni単o Southern Oscillation, or ENSO have been occurring against a background of global warming. To be more specific, in recent decades they’ve been happeningas the heat content of the world’s oceans has risen, and sea surface temperatures have increased, both duein large measure to humankind’s emissions of greenhouse gases.

Wimpy La Ni単a

The graph above shows what’s been happening to ocean heat content.

And the following one looks at temperatures at the surface:

Wimpy La Ni単a

This plot shows how sea surface temperatures have changedin three realms: the global tropics (red); the NINO3.4 region, the area of the Pacific used to diagnose El Ni単o and La Ni単a (gray); and the eastern tropical Pacific (blue). Each time series shows a three month running average of sea surface temperature anomalies calculated with respect to a base period of1981-2010. (Source: Columbia University International Research Institute for Climate and Society.)

As the gray line in the graphic above shows, sea surface temperatures in the NINO3.4 region where changes in SSTsare used to diagnose El Ni単o and La Ni単a have varied quite a lot. The large warmexcursions here are generally associated with El Ni単o, whereas cool ones are linked to La Ni単a. At the same time, itis difficult to discern any clear trend.

But also check out what’s been happening to sea surface temperatures in the global tropics overall, as well as the eastern tropical Pacific Ocean in particular (red and blue lines respectively). The trend since 1950 is clearly toward warmer temperatures, albeit with a lot of natural variation thrown in.

I should be clear that I’m not trying to make an argument that the current La Ni単a has been wimpy because ocean temperatures have gone up over the long run. The impact of climate change on the two sides of ENSO is an area of intense research.

Firm answers have been elusivebecausescientists have not been observing ENSO comprehensively for a long enough period. Moreover, El Ni単o and La Ni単a involve incredibly complex interactions between the atmosphere and oceans.And computer models are not quiteup to the challenge yet of fully simulating this interplay.

But it is difficult to imagine, at least for me, that all the energy accumulating in the Earth’s climatic system will not eventually have a clearly discernible and significantimpact on ENSO phenomena.

During the height of last year’s El Ni単o, Michael Jarraud, former secretary-general of the World Meteorological Organization, commented on this idea in a story at Columbia University’s State of the Planet blog. He noted that El Ni単o could be:

. . . playing out in uncharted territory. . . This naturally occurring El Ni単o event and human induced climate change may interact and modify each other in ways we have never before experienced.

Or to play off a famous saying byWallace Broecker, a renown scientist at TheEarth Institute of Columbia University: We’ve definitely beenpoking at the beast, and he’s clearly no longer asleep. Is that him just yawning? Or could it be the beginning of a growl?…

  • OWilson

    “This naturally occurring El Ni単o event and human induced climate change may interact and modify each other in ways we have never before experienced.”

    Lest we forget, there’s also another factor worth an occasional mention, :) ‘natural climate change’ :)

    Who knows, maybe even (gasp!) positive spin offs.

    Does it all have to be doom and gloom? :)

    • Gary

      But does “natural climate change” occur this quickly?

      • OWilson

        Where I live the natural temperature can go up 50 degrees in a single day, or 130 degrees in a year.

        “quickly” is a relative term, not a scientific one.

        • okiejoe

          And NOAA is talking about millions of square miles and you are talking about your backyard.

          • OWilson


            I’m talking about humanity’s tolerance of, and adaptation to, NOAA’s average temperature anomaly of 0.24 degrees over their 38 year satellite record!

          • icowrich

            Also, he’s talking about weather change, not climate change.

    • icowrich

      Positive spin offs like rising sea levels flooding coastal cities like Florida? Well, sure. There’s bound to be jobs that result from all of the cleanup and mitigation we’ll have to do. And, of course, natural disasters tend to incentivize innovation. Ultimately, we’ll develop more clean energy and get off of fossil fuels. That’s positive!

      • OWilson

        Do yourself a favor and get rid of the old chestnut that the world’s waterfront cities are washing away.

        They are all actually growing on land reclaimed from the water.

        Whole cities, airports, parks commercial and residential developments, Even military bases on new islands. From New York and Miami, to the Middle East, to China, Hong Kong, Japan and Korea. All growing!

        You can see this for yourself on Google Earth’s new Timeline Engine!

  • Fisherd

    It is more likely the weak trade winds are due to the collapsing atmosphere as a result of the approaching solar minimum. Until the solar cycle is figured into the La Nina equation, I doubt the experts climate models are going to be vary accurate for the next thirty years.

    The last time we have had these conditions was in the late 1700s and early 1800s, so that is where to do the research as to what we can expect now. During that period the low sunspot cycle was call the Dalton Minimum and winters in Europe were very cold. This was likely caused by a weak Gulf Stream, due to the weak trade winds in the Atlantic. Currently the Gulf Stream is weakening very quickly, but the experts fail to note the sun’s influence in driving the wind fields around the world. It is those very wind fields that drive the ocean currents and in turn drive the El Ninos and La Ninas.

    The greatest threats to mankind is fake news and junk science.

    • peggy.sanger

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ImaGeo is a visual blog focusing on the intersection of imagery, imagination and Earth. It focuses on spectacular visuals related to the science of our planet, with an emphasis (although not an exclusive one) on the unfolding Anthropocene Epoch.

About Tom Yulsman

Tom Yulsman is Director of the Center for Environmental Journalism and a Professor of Journalism at the University of Colorado, Boulder. He also continues to work as a science and environmental journalist with more than 30 years of experience producing content for major publications. His work has appeared in the New York Times, Washington Post, Audubon, Climate Central, Columbia Journalism Review, Discover, Nieman Reports, and many other publications. He has held a variety of editorial positions over the years, including a stint as editor-in-chief of Earth magazine. Yulsman has written one book: Origins: the Quest for Our Cosmic Roots, published by the Institute of Physics in 2003.


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