A new update from the World Meteorological Organization (WMO) predicts a 90% probability of an El Niño event in the second half of 2023. It is expected to be at least moderately strong. The WMO update combines forecasts and expert guidance from around the world.
Professor Petteri Talas, Secretary-General at WMO:
„The onset of El Niño greatly increases the likelihood of breaking temperature records and triggering extreme temperatures in many parts of the world and in the oceans. The declaration of El Niño by the WMO is a signal to governments around the world to mobilize preparations to limit the impacts on our health, our ecosystems and our economies.”
„Early warnings and anticipatory measures of extreme weather events associated with this major climate event are essential to save lives and livelihoods.”
El Niño occurs on average every two to seven years, and episodes typically last nine to 12 months. It is a naturally occurring climate pattern associated with warming sea surface temperatures in the central and eastern tropical Pacific Ocean. But this is taking place against the backdrop of a climate altered by human activities.
In anticipation of an El Niño event, a WMO report released in May predicted a 98% chance that at least one year in the next five years, and the five-year period as a whole, will be record-breaking and warmest on record. Set in 2016 when there was an exceptionally strong El Niño.
A WMO report in May, led by the UK’s Met Office with partners around the world, said there was a 66% chance that the annual average near-surface global temperature will temporarily exceed 1.5°C between 2023 and 2027. Industry levels for at least one year.
Chris Hewitt, Professor of Climate Services at WMO.
„In the next five years, we cannot say that we will exceed the 1.5 degrees Celsius specified in the Paris Agreement, because that agreement refers to long-term warming for several years. However, this is another wake-up call, or we still have to limit warming within the targets set in Paris in 2015, which were designed to significantly reduce the impacts of climate change. An early warning that you are not going in the right direction.
According to the WMO’s Global Climate Reports, 2016 was the warmest year on record because of the „double whammy” of a very powerful El Niño event and human-induced warming from greenhouse gases.
The impact of global warming usually becomes apparent in the year following its development, so will be most apparent in 2024. The average global temperature in 2022 was 1.15 °C above the 1850–1900 average because of a cooling triple dip La Niña.
El Niño events are generally associated with increased rainfall in southern South America, South America, the Horn of Africa, and parts of Central Asia. In contrast, El Niño can also cause severe drought in Australia, Indonesia, parts of South Asia, Central America and northern South America.
During the dry summer, El Niño’s warm waters can fuel hurricanes in the central/eastern Pacific Ocean, while inhibiting hurricane formation in the Atlantic basin. In general, El Niño has the opposite effect of the recent La Niña that ended in 2023.
Current status and outlook
Since February 2023, monthly mean sea surface temperature anomalies in the central-eastern equatorial Pacific have warmed significantly, from nearly half a degree Celsius above average (+0.44 in February, 2023) to half a degree Celsius above average (+0.47 in May, 2023).
During the week centered on June 14, 2023, warm sea surface temperature anomalies continued to increase, reaching a value of +0.9°C.
Combined evidence from oceanic and atmospheric observations points strongly toward the presence of El Niño conditions in the Pacific. However, there is some uncertainty due to weak ocean–atmosphere coupling, which is important for the amplification and sustenance of El Niño. It is expected to take approximately another month or so to see fully established connectivity in the tropical Pacific.
Global Seasonal Climate Update
El Niño and La Niña are major drivers of Earth’s climate system—but not the only ones. In addition to the long-established ENSO update, WMO now also publishes the regular Global Seasonal Climate Update (GSCU), which includes the impacts of other major climate drivers such as the North Atlantic Oscillation, the Arctic Oscillation and the Indian Ocean Dipole.
Because warmer-than-average sea surface temperatures are generally predicted over ocean regions, they contribute to the widespread prediction of above-normal temperatures over land. Without exception, positive temperature anomalies are expected over all landmasses in the Northern and Southern Hemispheres.
Forecasts for rainfall over the coming three months are similar to some of the canonical rainfall impacts of El Niño. The WMO ENSO and Global Seasonal Climate Updates are based on forecasts from the WMO Global Production Centers of Long-Range Forecasts and help governments, the United Nations, decision-makers and stakeholders in climate-sensitive sectors to mobilize products and protect lives and livelihoods. .
National Meteorological and Hydrological Services (NMHSs) closely monitor the evolution of El Niño conditions and their impacts on temperature and precipitation at the national and local levels. WMO will provide updated outlooks in the coming months as needed.
Probabilistic projections of surface air temperature and precipitation for July-September 2023 season. The base period is 1993-2009.
The World Meteorological Organization is the United Nations’ authoritative voice on weather, climate and water.