KXAN Austin

La Niña is happening more often than it should, climate scientists say

La Nina winter pattern (NOAA)

AUSTIN (KXAN) – Three years in a row, La Niña has brought warmer, drier weather to Central Texas. The climate pattern typically occurs every few years, but has recently occurred more often.

For climatologists, this is surprising. They’re saying in a warming world, we should see more El Niños, where wetter, colder weather hits Texas in the winter, than La Niñas.

So what is happening? Meteorologist Nick Bannin spoke with Robert Jnglin Wills, a climatologist with the University of Washington, about a recent study hoping to learn more about the odd occurrence.

According to the report, published by the Intergovernmental Panel on Climate Change, the El Niño-Southern Oscillation (ENSO) has changed due to climate change. It has become more frequent and more intense.

You can watch the interview in the video above or read the transcript below to learn more:

NICK BANNIN, KXAN NEWS: Dr. Jglin Wills joins us. A climatologist at the University of Washington. Dr., you’ve studied the relationship between ENSO and climate change. What does that study show?

ROBERT JNGLIN WILLS, CLIMATOLOGIST: So this study finds that, contrary to some ideas that have been out there that there’s been, over the last 40 years a trend towards more La Niña like conditions in the real world when climate models when we’re basing a lot of work on, say, for this one phenomena that it’s actually shouldn’t going the opposite way.

It’s a bit of a conundrum. But it could also be contributing to the La Niña conditions we’re currently experiencing now going into the third year of La Niña now,

BANNIN: Why would you be expecting El Nino with climate change, but instead, we’re getting La Niña more frequently.

JNGLIN WILLS: Basically, it’s that the region El Nino occurs, which is in the eastern tropical Pacific near the Galapagos Islands. This is a region that’s colder than the rest of the tropics. And this allows it to warm up more quickly with global warming, because it can’t evaporative really cool as efficiently.

That’s why we’d expect more El Nino like conditions in the future. But as for why we’re seeing something different now, it’s perhaps something not purely the greenhouse gas related change, but a secondary effect.

For example, one hypothesis could be that global warming is melting the Antarctic ice sheet, and that this melt water then goes into the ocean around Antarctica, cools it off there.

Some of this cooling can make its way into the Tropical Pacific through some more complicated atmosphere and ocean pathways and then lead to cooling in the eastern Pacific area near the Galapagos that does the same thing that happens during a La Niña

BANNIN: You don’t expect that La Nina pattern to continue with as much frequency going into the future, right, you expect more of a transition toward more El Ninos?

JNGLIN WILLS: Eventually, we would expect a transition towards more El Nino and a warmer climate. Evidence for that comes from looking at the ancient past periods. 1000s to hundreds of 1000s or even millions of years ago, when the periods where warmer.

We find evidence from fossilized corals that there were more linear like conditions, but we don’t know on what timescale that that that switch could happen. So it depends why these current linear trends are happening, which we don’t have a complete answer to yet.