Shifts in #ElNiño May Be Driving #Climate Extremes in Both Hemispheres — Inside Climate News #ActOnClimate

La Niña intensifies the average atmospheric circulation—surface and high-altitude winds, rainfall, pressure patterns—in the tropical Pacific. Over the contiguous United States, the average location of the jet stream shifts northward. The southern tier of the country is often drier and warmer than average. NOAA illustration.

Click the link to read the article on the Inside Climate News website (Bob Berwyn). Here’s an excerpt:

Global warming is shifting cyclical temperature swings in the Pacific Ocean, and that affects floods in Australia, fires in South America and even temperature in the polar regions.

Other “unthinkable” extremes hit the Northern Hemisphere in the months before that. A December wildfire in the Rocky Mountain foothills of Colorado completely changed how some forest and fire scientists see the fire risk in that area, and the Pacific Northwest heat wave that started in June 2021 was an extreme not forecast by climate models. As that heat wave ebbed in July, parts of several German towns were destroyed by flooding rainstorms that were intensified by global warming. And in recent days, temperatures surged to 50 degrees Fahrenheit in the Siberian Arctic near the North Pole and above the adjacent Arctic Ocean.

Scientists exploring possible connections between the remarkable series of extremes in both hemispheres say they are increasingly certain that the powerful El Niño-La Niña cycle in the Pacific Ocean is one of the key links. New research shows the cycle has shifted in a way that is likely to fuel extremes, including wild swings between heat and drought and flooding rains.

In the El Niño/Southern Oscillation (ENSO), huge masses of water surge eastward and westward every two to seven years along a vast region of the equatorial Pacific. One of the strongest El Niños on record in 2016 helped boost the average global temperature to a new record high that year.

It’s Happening. Now

The most recent global science report from the Intergovernmental Panel on Climate Change projected that the global warming fingerprint on the El Niño-La Niña cycle would become apparent after about 2050. But the accelerating pace of record-breaking weather events shows that the destructive effects are already here, said Wenju Cai, director of the Center for Southern Hemisphere Oceans Research at the Commonwealth Scientific and Industrial Research Organisation in Australia…

Oceans hold 93 percent of the heat trapped by greenhouse gasses, and the tropical Pacific is the biggest tank for this heat, pure energy for the climate system. The El Niño-La Niña cycle is the pump distributing that energy, as heat and moisture, to the global climate system, to the east and west of the equator, as well as the north and south.

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