Our result of a greenhouse-induced increase in occurrences of
extreme La Niña events is consistent with an increased frequency of
extreme El Niño that provides a favourable condition for extreme
La Niña. This occurs amid a faster warming over the Maritime
continent region than the central equatorial Pacific and increasing
vertical temperature gradients that are conducive to extreme La
Niña events. We note that the weakening Walker circulation that
underlies the projected increase in extreme ElNiño frequency is still
amatter of debate andmodel biases in ElNiño/SouthernOscillation
simulation can introduce uncertainties. Nevertheless, the overall
increased frequency in extreme LaNiña events,most of which occur
in the year after an extreme El Niño, has important implications. It
means more occurrences of devastating weather events, and more
frequent swings of opposite extremes fromone year to the next, with
profound socio-economic consequences.