There is a 60% chance that La Nina, a weather phenomenon that lowers ocean surface temperatures, will occur in the July-September period. The return of the cool La Nina weather phenomenon this year will help temperatures cool somewhat after months of record-setting global temperatures. The impact is likely to be felt over the next few months as the warm El Nino weather pattern – which has fueled a rise in global temperatures and extreme weather around the world since mid-2023 – shows signs of ending. The World Meteorological Organization (WMO) of the United Nations (UN) said on June 3 that El Nino has ended.
However, WMO warns that global temperatures will continue to increase in the long term due to human-caused climate change. This will make extreme weather events worse and upset seasonal temperature and rainfall patterns. While El Nino heats the ocean surface, La Nina is a lowering of ocean surface temperatures in large areas of the tropical Pacific, accompanied by wind, rain, and changes in air pressure. In many places, especially in the tropics, La Nina brings the opposite climatic effects of El Nino, leading to drought in some places and heavy rain in others.
WMO said that there is a 60% chance of La Nina occurring in the period July – September and a 70% chance in August – November. The possibility of El Nino redeveloping is very low. Every month since June 2023, when El Nino occurred, has set a new high temperature record. Up to now, 2023 is also the warmest year ever recorded globally. “The end of El Nino does not mean that long-term climate change will stop, as the planet will continue to warm as greenhouse gases trap heat. High sea surface temperatures still play an important role in the coming months,” Ko Barrett, deputy secretary-general at WMO, emphasized.
Much of the Earth’s excess heat due to climate change is stored in the oceans. In the US, the National Oceanic and Atmospheric Administration (NOAA) took La Nina into account when forecasting this year’s Atlantic hurricane season. According to NOAA, 4-7 strong hurricanes are expected in the Atlantic from June to November. The upcoming Atlantic hurricane season is expected to be more active than usual due to a combination of factors, including near-record warm ocean temperatures in the Atlantic, the development of the La Nina phenomenon in Pacific, Atlantic trade winds, and decreased wind shear.
The past nine years have been the warmest years on record, even with the cooling effect of the La Nina period that lasted from 2020 to early 2023, according to WMO. The latest El Nino, which peaked last December, was one of the five strongest in history.