Following a brief interlude of “neutral” sea surface temperature conditions this summer, La Niña has returned to the tropical Pacific Ocean. The cool phase of the El Niño-Southern Oscillation climate pattern is expected to persist through winter.
Between January and April 2010, temperatures in the Pacific were under the warming influence of a fading El Niño episode. Meanwhile, higher latitudes of the Northern Hemisphere were dominated by a strong negative phase of the Arctic Oscillation.
Two natural climate patterns, the Arctic Oscillation and the El Niño-Southern Oscillation, had strong influences on the patterns of unusually warm and unusually cool spots worldwide in early and late 2010.
Computer climate models help scientists such as Dave Dewitt predict the life cycles of individual El Niño or La Niña events and their effects on weather patterns throughout the world. While the accuracy of these models continues to improve, they still have limitations.
Will climate change affect frequency or intensity of El Niño and La Niña? There is still little consensus among scientists on this, explains the International Research Institute for Climate and Society’s Lisa Goddard.