There’s A 60 Percent Chance El Niño Could Last All Year

פורסם: 10 באפר׳ 2015, 11:40 על ידי: Sustainability Org   [ עודכן 10 באפר׳ 2015, 11:40 ]
by Joe Romm Posted on April 10, 2015

California Temps

California’s January-March temperature since 1895. An arrow points to state’s amazing recent warmth. (NOAA via Climate Central)

The National Oceanic and Atmospheric Administration (NOAA) is predicting a 60 percent chance that the El Niño it declared in March will continue all year. An El Niño is a weather pattern “characterized by unusually warm ocean temperatures in the Equatorial Pacific.”

Robust El Niños are associated with extreme weather around the globe. They also generally lead to global temperature records, as the short-term El Niño warming adds to the underlying long-term global warming trend. El Niños are typically California drought-breakers, but as the top graph shows, that hasn’t been the case so far.

As I discussed last week, some climatologists believe that we may be witnessing the start of the long-awaited jump in global temperatures — a jump that could be as much as as 0.5°F. It already appears likely that March will be hot enough to set yet another global record for the hottest 12 months on record (April 2014 through March 2015) and a global record for hottest start to a year (January through March) ever.

NOAA released its “consensus probabilistic forecast” of the El Niño Southern Oscillation (ENSO) for the rest of this year, from its Climate Prediction Center (CPC) and Columbia University’s International Research Institute (IRI) for Climate and Society. Note that the ENSO state — El Niño, neutral, or La Niña — is generally based on the sea surface temperature (SST) anomaly in the NINO3.4 region of the Equatorial Pacific.

ENSO chances

NOAA concludes there’s about a “70% chance that El Niño will continue through Northern Hemisphere summer 2015, and a greater than 60% chance it will last through autumn.”

I asked climatologist Kevin Trenberth of the National Center for Atmospheric Research what a prolonged El Niño would mean for the planet and California. He told me it “goes along with the jump” in global temperatures he has said is imminent.

California is a more complicated situation for a few reasons. Trenberth notes that the famous song “It never rains in Southern California” is mostly accurate “at least from May through October – and Governor Jerry Brown has every right to be concerned.” If a full-blown El Niño develops over the year, “then the prospects go up a LOT for rains in California” during the state’s traditional rainy season, late October through March, which has not been very rainy at all in the last few years.

Climate expert Professor John Abraham also noted that a full-blown El Niño “just might bring some relief from this unbelievable drought.” But he was quick to note that “an El Niño will also break more temperature records and may make 2015 the hottest year ever. It will also bring extreme weather to other parts of the planet so this El Niño is a double-edged sword.”

In fact, on Monday, NOAA’s Climate Prediction Center released this “seasonal outlook” for U.S. temperatures April to June. It combines “the effects of long-term trends, soil moisture, and, when appropriate, ENSO”:

NOAA spring outlook

If that forecast comes true, then California and the West are due for more blistering temperatures, which would likely make the drought even worse in the near term.

Finally, most of Brazil is suffering through a devastating drought, too. São Paulo “is suffering its worst drought in almost a century.” Dr. Trenberth writes, “These water crises both in CA and Brazil (and perhaps we can add Australia) are excellent analogs for the sort of problems I expect to become more common with global warming. Water is likely to be the biggest pressure point on society.”

Indeed, many recent studies have projected that large parts of the world including much of the Southwest, Great Plains, Brazilian Amazon, and Australia will turn into near permanent dust bowls if the world doesn’t slash carbon pollution soon. The time to act is now.