Science Source

Continued increase of extreme El Nino frequency long after 1.5°C warming stabilization

States that the Paris Agreement aims to constrain global mean temperature (GMT) increases to 2 °C above pre-industrial levels, with an aspirational target of 1.5 °C
States that however, the pathway to these targets and the impacts of a 1.5 °C and 2 °C warming on extreme El Niño and La Niña events—which severely influence weather patterns, agriculture, ecosystems, public health and economies—is little known
Demonstrates, by analysing climate models participating in the Climate Model Intercomparison Project’s Phase 5 under a most likely emission scenario, that extreme El Niño frequency increases linearly with the GMT towards a doubling at 1.5 °C warming
Finds that this increasing frequency of extreme El Niño events continues for up to a century after GMT has stabilized, underpinned by an oceanic thermocline deepening that sustains faster warming in the eastern equatorial Pacific than the off-equatorial region
Results indicate little to no change in the frequency of extreme La Niña events under 1.5 °C or 2 °C warming