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Disasters & Extreme WeatherHurricanes & CyclonesScience

La Nina to Blame for Extreme Weather Events

It won’t come as a big surprise, but La Niña – or “the girl” in Spanish – is to blame for recent extreme weather events that have taken place in Africa and Australia.

Scientists at the International Research Institute for Climate and Society (IRI), part of Columbia University’s Earth Institute, expect “moderate-to-strong” La Niña conditions to continue causing additional shifts in rainfall patterns across many parts of the world.

“Based on current observations and on predictions from models, we see at least a 90 percent chance that La Niña conditions will continue through March,” said IRI’s chief forecaster, Tony Barnston.

None of this is new information. The UN’s weather agency – the World Meteorological Organization – reported late in January the same information suggesting that this current La Niña could even last into the second quarter of 2011.

However climate scientists from the University of Columbia have found La Niña’s fingerprints in extreme weather events the world over; the devastating floods in Pakistan in 2010, flooding in West Africa and South Africa, not to mention the recent floods in Queensland, Australia, which saw an area equal to the combined size of France and Germany underwater.

This latest La Niña is also to blame for Cyclone Yasi, one of the strongest cyclone’s to hit Australia, the second most damaging cyclone on record after Cyclone Tracy struck in 1974.

It isn’t just rainfall that La Niña is bringing to the world though. East Africa is currently enduring drought conditions which have sparked food-security concerns in areas that lack proper irrigation, including parts of Somalia, Kenya, Ethiopia and Tanzania.

Predictions also show that parts South America, Asia and the southern U.S. may also see lower rainfall for the first quarter of 2011.

“Last year’s transition from El Niño to La Niña was about the most sudden we’ve ever had,” Barnston said. “When we had rapid flips like this in the past, we sometimes ended up having a two-year La Niña, such as right after the El Niño episodes of 1972 to 1973 and 1997 to 1998.”

La Niña conditions normally persist for 9 to 12 months, peaking around the end of the year, but 2010 was a different yea for climate scientists, with the first four months of the year seeing El Niño conditions prevailing in the tropical Pacific.

Baronston notes though that it is unknown whether the current La Niña will flip as suddenly, or leave us with a second year of La Niña conditions. “Even if we do have a second year of La Niña developing in northern summer 2011, we expect at least a brief return to neutral conditions from May to July of 2011.”

Source: Columbia University
Image Source: NASA




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