Pham Thi Thanh Nga, director of the institute, said the El Nino phenomenon reached its peak in November and December 2023. Although the phenomenon is still strong at the moment, it is gradually weakening.
Over the past eight months, El Nino has caused temperatures in Vietnam to rise by 0.5 to 2 degrees Celsius compared to the average in previous years.
Several localities experienced record temperatures from April to July last year. On May 7 last year, a weather station in Nghe An recorded a temperature of 44.2 degrees, the highest ever recorded in Vietnam.
Due to the effects of El Nino, precipitation levels have been below the annual average for many years and have remained so in recent months.
Last year, eight tropical storms and depressions were active in the South China Sea, five fewer than the annual average.
Only one storm directly affected the territory, six fewer than the annual average.
El Nino is expected to persist and affect Vietnam’s weather conditions over the next 3 to 4 months, she said, adding that new record temperatures could be seen.
Precipitation will be below the annual average across the country, particularly in southern locations.
Due to low levels of precipitation over several months, combined with high temperatures, the south-central, southern and central highlands regions will experience droughts and water shortages.
Tropical storms and depressions are unlikely to appear over the next 3 to 4 months. Summer monsoon winds will arrive later than usual in previous years.
Nga said weather forecast models all show El Niño is in rapid decline and could become neutral by early summer, either in late May or early June.
It will give way to the La Nina phenomenon, which should appear at the end of summer, around August.
The impacts of El Niño and La Niña are more pronounced over a period of 1 to 3 months.
Nga said as El Niño gives way to La Niña, weather and climate will exhibit anomalies, outside of the norms that are difficult to predict. Close monitoring and rapid updates would therefore be essential to respond, Nga said.
If La Nina appears in the second half of this year, tropical storms and depressions could arrive more frequently, as well as heavy rains and flooding in central and southern Vietnam. As urbanization occurs more quickly, flooding will also occur more frequently, Nga warned.
Nga said that when looking at historical records, a strong El Niño in winter usually leads to La Niña in the summer or fall of the following year, such as in 1972-1973, 1997-1998 or 2015-2016 .
How quickly El Niño transitions into La Niña will determine its impact on global and regional weather patterns, and the transition period could result in abnormal weather conditions, which may be more difficult for weather models to predict.
Nga also noted that La Nina does not always result in serious natural disasters. Its impacts would depend on multiple factors, and whether it is El Niño or La Niña, high temperatures would still be observed in summer, particularly in cities, and floods and landslides could still be frequent during the rainy season.
Typical La Niña periods were observed in 1998-2000, 2007-2008, 2010-2011 and 2020-2022. A severe cold spell that lasted 38 days from January to February 2008 killed around 110,000 cattle and poultry and destroyed 180,000 ha of rice fields, resulting in an estimated loss of VND400 billion ($16.23 million) .
The La Nina period between 2020 and 2022 also saw several tropical storms and depressions accompanied by flooding and landslides, resulting in the death or disappearance of 357 people and property damage amounting to over 39.96 trillion dong in 2020.
