The World Meteorological Organization projected that the Earth will experience its third year in a row of a La Niña climate pattern, placing the odds at 70%.
The WMO said that La Niña conditions in the Pacific Ocean intensified through the late summer, increasing the organization’s confidence. La Niñas generally are caused by strong trade winds that force cooler water in the South Pacific farther north. This generally forces warmer ocean currents farther west in the Pacific.
“It is exceptional to have three consecutive years with a La Niña event. Its cooling influence is temporarily slowing the rise in global temperatures – but it will not halt or reverse the long-term warming trend,” said WMO Secretary-General Prof. Petteri Taalas.
In the United States, a La Niña generally brings warm and dry winters for most of the south and east, while the northwestern U.S. normally has cooler and wetter winters.
La Niñas also raise the risk of extreme drought in the southern U.S.
The effect of La Niña can be worse elsewhere.
“The worsening drought in the Horn of Africa and southern South America bear the hallmarks of La Niña, as does the above average rainfall in South-East Asia and Australasia,” Taalas said. “The new La Niña Update unfortunately confirms regional climate projections that the devastating drought in the Horn of Africa will worsen and affect millions of people.”