The current super El Niño event is forecast to strengthen further between August and October, according to the World Meteorological Organisation (WMO). The organisation's latest climate models predict the pattern will develop into a "strong" event, bringing above-average temperatures worldwide and major shifts in rainfall.
UN Secretary-General António Guterres said El Niño is "strengthening, adding fuel to a planet already on fire with scorching heat domes, apocalyptic wildfires and record hot seas."
The WMO predicts sea surface temperatures in key regions will exceed 2.9°C (5.2°F) above the seasonal average. El Niño events typically peak between November and February, meaning their strongest effects on global weather are usually felt at the start of the following year.
How the El Niño pattern develops
El Niño and the cooling La Niña are phases of a natural climate cycle known as the El Niño Southern Oscillation. In a normal year, trade winds blow westwards across the Pacific, pushing warm water away from South America and allowing colder water to rise along the coast.
During El Niño, those winds weaken or reverse, letting warm water build up in the tropical Pacific. That buildup can raise the global average temperature and disrupt weather patterns worldwide. In July, sea surface temperatures in the affected waters exceeded 2.1°C (3.8°F) above average, and forecasts suggest further warming is coming.
The WMO also warns that El Niño has arrived alongside a positive Indian Ocean Dipole, a pattern in which the western Indian Ocean warms while the eastern part cools. Combined with El Niño, that temperature gradient amplifies risks of drought, flooding and wildfires, particularly around the Indian Ocean.
Temperature and rainfall impacts
WMO Secretary-General Celeste Saulo said this El Niño, developing against a backdrop of unprecedented ocean heat and rising temperatures, "provides governments and communities with a window of opportunity to anticipate risks and act before impacts unfold."
The clearest consequence of a strengthening super El Niño is that global temperatures will stay above average into next year. El Niño itself is not caused by climate change, but the extra heat it generates combines with warming already driven by human activity. The biggest effects are expected in Southern Europe, Africa, East Asia, Central America, South America, New Zealand and the Caribbean.
The pattern will also reshape rainfall between August and October. The Horn of Africa, western North America and parts of Central Asia face much wetter conditions and a considerable flood risk, while Northern Europe, most of Australia, the Indian subcontinent and southern Central America are expected to see much lower rainfall than average.
Wildfires and record heat already underway
The warning comes as several regions are already dealing with extreme heat and destructive fires. In Europe, wildfires have swept across France and Spain, forcing the evacuation of more than 330,000 people.
In the worst-affected areas of France, more than 162 square miles (42,000 hectares) of land has burned, making it one of the largest forest fires since World War Two. In England and Wales, the Met Office has officially logged the driest July on record. England received just 6.5mm of rainfall across the entire month, about 10 per cent of its long-term average and less than half the previous record of 13.4mm, set in 1911.
East Asia has also been gripped by record-breaking heat. South Korea asked people to stop all outdoor activity as temperatures reached 42.5°C (108.5°F), the highest recorded there in 100 years.
