El Niño has been strengthening for several months and is already having a significant effect on weather patterns around the globe. Countries including Indonesia, India and the United States have reported droughts, floods and heatwaves, in line with projections that the phenomenon would intensify extreme weather.
The World Meteorological Agency says the record-breaking El Niño will strengthen further and persist until at least 2027. Its effects are already visible in several regions, from smoke-choked Southeast Asian cities to storm-heavy ocean basins.
Indonesia battles its worst wildfire season since 2015
Indonesia typically becomes drier and hotter in El Niño years, and this year it is contending with its worst wildfire season since 2015. Since January, at least 895,657 hectares of land, nearly six times the size of Greater London, have burned. That is more than twice the area burned last year, when El Niño was not a factor.
The fires have led to school closures and a rise in hospital admissions across the country. Millions of people in Sumatra and Kalimantan have been exposed to toxic haze, and around 175,000 people have suffered respiratory illness. More than 40,000 of those cases, ranging from coughs to bronchitis and more serious conditions such as pneumonia, involve toddlers.
Record hurricane activity in the Pacific, a quiet Atlantic
In the eastern Pacific, where El Niño tends to strengthen hurricane activity, the season has been very active so far. There have been 22 named storms and 12 hurricanes, 10 of them major, a count already above the number that would typically form in a full average season, with two months still to go.
El Niño brings higher ocean temperatures and weaker winds high in the atmosphere, which makes it easier for storms to strengthen. Hurricane Polo is one example. It intensified rapidly, producing wind gusts of 180 mph (285 km/h), fuelled by very warm water. Polo was one of three hurricanes churning in the same basin at the same time, alongside Odalys and Nolo.
Earlier in September, exceptional ocean heat produced three simultaneous hurricanes in the central and eastern Pacific: Lowell, Karina and Marie. Before this year, the last time three Pacific hurricanes were active at once was 2015.
The Atlantic, by contrast, has remained unusually quiet. El Niño tends to increase wind shear in the north Atlantic, which tears storms apart and limits their formation. So far there has been only one hurricane, Isaias, which made landfall in the Florida Panhandle and Alabama. It was the latest-forming hurricane on record in the satellite era, which begins in the 1960s. The previous record was 11 September, set in 2002 and 2013.
In an average season, there would have been 10 named storms, five hurricanes and two major hurricanes by this point. This year there have been only eight tropical storms: Arthur, Bertha, Cristobal, Dolly, Edouard, Fay, Gonzalo and Hanna.
India’s monsoon shortfall and typhoons near Japan and China
In India, essential monsoon rainfall has been 13% below average. The Indian Meteorological Department would still consider that within the ‘normal’ range, but the national average hides wide regional differences. Central India received roughly its expected rainfall, while the east and north-east were about 26% drier than average and placed in ‘exceptional’ drought. Southern states were 24% drier than average.
Even where rainfall came close to average, it did not fall steadily, as is typical during the monsoon. Instead it alternated between long dry spells and extreme downpours. This adds stress and vulnerability for agricultural yields. Scientists note that India is influenced by several weather patterns that can affect the monsoon, so El Niño may not have been the only factor.
Further west, eastern China and Japan have also had an active season. Storms including Maysak and Dujuan have brought widespread floods and landslides. According to the Japan Meteorological Agency, 10 tropical cyclones have formed in the western Pacific Ocean, the highest number in a season since 1966.
During El Niño, the warmer Pacific shifts wind patterns, so cyclones tend to form further east, away from Japan and eastern China. That gives storms a longer distance and more time over warm water, allowing them to gain energy and become more intense typhoons before they reach land. Scientists believe additional typhoons are likely to develop this year, with the potential for further impacts on Japan or eastern China.
