PARIS, France – In a formal announcement Thursday, the U.S. National Oceanic and Atmospheric Administration (NOAA) has confirmed the arrival of El Niño, the warm phase of the naturally occurring tropical Pacific climate cycle that is closely tied to rising global temperatures and widespread disruptive weather patterns across the planet.
El Niño forms as part of a seesawing fluctuation in Pacific Ocean surface temperatures and trade wind patterns that originates across the tropical Pacific, but its ripple effects can alter weather patterns thousands of miles from its source, amplifying the risk of extreme events ranging from severe drought to catastrophic flooding.
While climate scientists emphasize that no two El Niño events are identical, and a strong event – which current forecasts project for this cycle – does not guarantee specific extreme outcomes, it significantly shifts the probability of such impacts toward higher risk.
To understand El Niño’s global reach, it is first necessary to break down how the pattern alters baseline atmospheric and oceanic conditions. During an El Niño cycle, trade winds that normally blow westward across the tropical Pacific weaken, allowing warm surface water that typically accumulates near Indonesia to shift eastward toward the coasts of South America. This eastward shift of warm water pulls patterns of evaporation, cloud formation and rainfall along with it, reshaping seasonal weather across every continent.
### Impacts Across the Asia Pacific
For much of the Asia Pacific, this shift translates to drier-than-average conditions and elevated drought risk. El Niño is known to suppress the South Asian summer monsoon, a critical weather system that delivers the seasonal rainfall that sustains agricultural production and livelihoods for hundreds of millions of people across India and the broader Indian subcontinent.
Australia faces particularly elevated risks: the continent typically experiences above-average temperatures during El Niño, increasing the likelihood of severe drought, prolonged heatwaves and destructive wildfires. Eastern Australia most often sees the most significant rainfall deficits, while the northern Australian wet season tends to start later than normal. One small silver forecast for the continent is a reduced risk of tropical cyclone activity during the cycle. Some of the most severe droughts in Australia’s modern recorded history have been tied to past El Niño events, though researchers reiterate that even strong cycles do not always deliver below-average rainfall across the whole country.
### Effects on African Weather Patterns
El Niño’s impact on Africa is split across regions. Parts of the Horn of Africa typically see above-average rainfall during El Niño cycles, but most of southern, western, central and eastern Africa faces a high risk of drier-than-normal conditions that escalate drought vulnerability.
Last month, the World Meteorological Organization (WMO) warned of a high probability of below-average rainfall during the critical June-to-September growing season rainy period across a swathe of East Africa, including South Sudan, Uganda, Ethiopia, Djibouti, most of Eritrea, Sudan, and western and coastal Kenya. The most recent 2023-2024 El Niño cycle brought southern Africa its most severe drought in over 100 years, leaving an estimated 61 million people across the region in need of life-saving humanitarian assistance, according to data from the Food and Agriculture Organization.
### Shifting Extremes Across the Americas
Across the Americas, El Niño again brings divergent impacts depending on region. Parts of western South America, including coastal Peru and Ecuador, typically see well above average rainfall during strong El Niño events, raising the risk of catastrophic flooding and deadly landslides. The 2023-2024 El Niño cycle was already linked to severe deadly flooding in southern Brazil in 2024.
By contrast, northern Brazil – including large swathes of the Amazon rainforest – faces drier-than-average conditions that increase the risk of severe drought and out-of-control wildfires.
For the United States, El Niño shifts the North Pacific jet stream southward, leading to stormier, wetter and snowier conditions across the southern U.S. during the winter months. The U.S. West Coast also sees an elevated risk of high-tide coastal flooding during El Niño cycles.
The pattern also alters hurricane activity across both major ocean basins. Stronger upper-level winds in the Atlantic inhibit tropical cyclone development, leading NOAA forecasters to already project a below-normal Atlantic hurricane season this cycle. However, the extra warm surface water from El Niño fuels more tropical cyclone activity across the central and eastern Pacific during the Northern Hemisphere summer.
### El Niño’s Role in Global Temperature Records
El Niño events typically reach their peak strength around December, when the abnormally warm surface waters across the tropical Pacific reach their maximum geographic extent. However, the ocean releases this stored heat into the atmosphere gradually, meaning the biggest impact on global average temperatures often occurs in the year after El Niño first develops.
Many of the hottest years on record – including 1998, 2010, 2016, 2023 and 2024 – have either occurred alongside major El Niño events or followed in their wake. Speaking to Agence France-Presse, multiple climate scientists projected that 2027 is likely to surpass 2024 as the hottest year ever recorded globally, driven in large part by the warming influence of this newly declared El Niño cycle.
