Graphic of El Niño and La Niña conditions. Provided by climate.gov
The El Niño Southern Oscillation (ENSO) is a periodic fluctuation in sea surface temperature (El Niño/La Niña) and the pressure pattern of the overlying atmosphere (Southern Oscillation) across the equatorial Pacific Ocean. Through its atmospheric teleconnections, ENSO is also the major source of seasonal predictability and driver of global climate and extreme events. Future changes in the seasonal evolution of ENSO during its onset and decay phases have received little attention by the research community. Due to its global impact, it’s imperative that these changes be better understood.
In a new Nature Communications article, authors Hosmay Lopez, Sang-Ki Lee, Dongmin Kim, Andrew T. Wittenberg, and Sang-Wook Yeh examines a large suite of climate models driven by historical and projected future warming—in order to better understand potential future changes in El Niño’s onset, decay, and remote impacts.
The study reveals that projected future warming will result in El Niño events that grow at a faster rate, persist longer over the eastern and far eastern Pacific, and have stronger and distinct remote impacts via teleconnections. These changes are driven by significant changes in the general state of the tropical Pacific, dominant ENSO feedback processes, and an increase in westerly winds in the western equatorial Pacific. They may lead to more significant and persistent global impacts of El Niño in the future.
The authors note that although climate simulations have substantially improved over the past decade, a number of remaining model biases could affect the results presented here, demanding further R&D. In addition, the paper identifies a need for longer simulations and multi-model ensembles, and calls for further studies to confirm the contrasting ENSO projections between low- and high-resolution simulations.
Funding for this project was provided in part by the NOAA Climate Program Office, MAPP program.
Read the full study here.