Causing unusually warm waters off the coast of Central and South America, an El Niño event refers to a large scale ocean and atmospheric interaction that results in the warming of sea surface temperatures across the Equatorial Pacific. In addition, El Niño can lead to warmer than average temperatures and significant regional seasonal precipitation anomalies across North America, and can impact weather patterns, ocean conditions, and marine fisheries around the world. Because El Niño events result in a large flux of energy from the ocean to the atmosphere, overall, the global mean surface temperature (GMST) is usually higher than normal during and immediately following an El Niño event.
In a new Environmental Research Letters article, authors Chia-Wei Hsu and MAPP-funded PI Jianjun Yin analyzed 38 climate models in the Fifth Coupled Model Intercomparison Project (CMIP5) to find the likelihood of El Niño breaking the Global Mean Surface Temperature (GMST) record during the 21st century. Because El Niño events occur on top of a global temperature trend, they can often cause all-time GMST records that take a few years for the trend to catch up with and exceed. It was found that under a low emission scenario, one out of three El Niño events would be expected to break an existing GMST record. This probability significantly increased to four out of five events when running a high emission scenario. In addition, it was found that half of strong El Niño events would break the GMST record, whereas, only one-fifth of weak El Niños would break the GMST in a low emission scenario.
It was generally found that El Niño would account for more than half of record breaking occurrences in all emission scenarios..
The Modeling, Analysis, Predictions, and Projections (MAPP) Program is a competitive research program in NOAA Research’s Climate Program Office. MAPP’s mission is to enhance the Nation’s and NOAA’s capability to understand, predict, and project variability and long-term changes in Earth’s system and mitigate human and economic impacts. To achieve its mission, MAPP supports foundational research, transition of research to applications, and engagement across other parts of NOAA, among partner agencies, and with the external research community. MAPP plays a crucial role in enabling national preparedness for extreme events like drought and longer-term climate changes. For more information, please visit www.cpo.noaa.gov/MAPP.