Scientists say a cooling La Nina pattern is emerging in the Pacific Ocean's surface temperatures, with a 60% chance of developing during July-September.
The return of the cooling La Nina weather pattern this year will bring some relief from the record-breaking global temperatures of recent months. The impact is likely to be felt in the coming months as the warm El Nino pattern — which has fueled global temperature increases and extreme weather around the world since mid-2023 — is waning, the United Nations' (UN) World Meteorological Organization (WMO) said on Friday.
La Nina can bring heavy rains to some areas and droughts to others. (Photo: Somchai Poomlard)
While El Nino warms the surface of the ocean, La Nina is the cooling of large areas of the Pacific Ocean's surface temperatures, along with changes in wind, rain and air pressure. It often brings opposite climate impacts in many parts of the world, particularly in the tropics, leading to droughts in some areas and increased rainfall in others.
The WMO said there is a 60% chance of La Nina during July-September, increasing to 70% during August-October. The chance of El Nino re-emerging is very low.
Most of the Earth's excess heat from climate change is stored in the oceans. In the United States, the National Oceanic and Atmospheric Administration (NOAA) has factored in La Nina in its forecast for this year's Atlantic hurricane season. NOAA predicts four to seven major hurricanes in the Atlantic from June through November.
"The upcoming Atlantic hurricane season is expected to be above-average because of a combination of factors including warmer-than-average sea surface temperatures in the Atlantic, the ongoing La Nina in the Pacific, weaker trade winds, and reduced vertical wind shear," NOAA said.
However, the WMO warns that the long-term global warming trend due to human-induced climate change will continue. This will make extreme weather events more severe and disrupt seasonal rainfall and temperature patterns.
Every month since June 2023, when El Nino took hold, set a new global temperature record. So far, 2023 is on track to be one of the warmest years on record.
"The end of the El Nino does not mean that the long-term global warming trend is over, as the planet continues to warm because of greenhouse gases trapping heat. High sea surface temperatures will continue to play a role in the coming months," said Ko Barrett, WMO副秘书长强调.
The past nine years have been the warmest on record, even with the cooling influence of a La Nina that lasted from 2020 to early 2023, according to the WMO. The latest El Nino, which peaked in December last year, was one of the five strongest on record.
Summary
A cooling La Nina pattern is expected to develop in the Pacific Ocean's surface temperatures, bringing relief from the record-breaking global temperatures of recent months. However, the long-term global warming trend due to human-induced climate change will continue, making extreme weather events more severe.