UN climate experts said on Tuesday warned that temperatures in almost all parts of the world will likely rise between now and April despite the cooling influence of the latest La Niña weather phenomenon, which has passed its peak.
“Impacts on temperatures, precipitation and storm patterns continue,” the World Meteorological Organization (WMO) said in a statement.
It noted that above-normal temperatures in the next three months are expected in western, central and eastern Asia and over the southern half of North America, and that there is a moderate likelihood (65 per cent) that the La Niña event will continue into April.
Above-normal temperatures are also likely over most northern high latitudes – except northwestern North America – southern, central and eastern parts of South America, and equatorial and northern Africa, WMO said.
Below-normal temperatures are more likely for northern South America.
Turning to rainfall, WMO said that there were “increased chances of unusually wet conditions” that were consistent with La Niña’s effects on regional climates, over much of South East Asia, Australia and northern South America and islands in Melanesia.
Southern Africa may also see above-normal rainfall, the agency said, along with “an increased probability of above-normal precipitation (possibly as snow) over much of the Northern Hemisphere north of about 45 degrees North”.
La Niña refers to the large-scale cooling of ocean surface temperatures in the central and eastern equatorial Pacific Ocean, along with changes in winds, air pressure and rainfall in the tropics.
It has been in place since August 2020, WMO said, “but this was not enough to prevent 2020 from being one of the three warmest years on record”.
La Niña usually has the opposite impact on weather and climate to El Niño, which is the warm phase of the so-called El Niño Southern Oscillation (ENSO).
Although El Niño and La Niña are major drivers of the Earth’s climate system, so too is “human-induced climate change, which is increasing global temperatures, exacerbating extreme weather, impacting seasonal rainfall patterns and complicating disaster prevention and management,” said WMO Secretary-General, Professor Petteri Taalas.
According to WMO data, East Africa’s short but important rainy season from October-December saw generally drier conditions in the north and east, with wetter or nearer normal conditions in the south and west. Similar mixed rainfall patterns are forecast between now and April.
Many parts of southern Africa have seen above-average rainfall, WMO noted, with a significant exception being parts of Mozambique and Madagascar, which have seen little or no rainfall.