Why El Nino brought a record drought to Southeast Asia

From the prolonged drought in South Africa and Southeast Asia to the record high number of storms on the US coast, the unprecedented strong El Nino phenomenon is raging and changing the climate of the world.

Walker circulation in normal conditions (pictured above) and when the El Nino phenomenon takes place (pictured below).Photo: NOAA.

Despite signs of a slight decrease, the widespread impact of El Nino will last for weeks or months ahead. This could benefit people in California, USA, who are enjoying the El Nino rains, but will be bad news for many areas suffering from droughts, forest fires, water shortages and food like Indonesia.

Earlier this year, weather changes related to the phenomenon of El Nino caused losses of up to billions of dollars, pushing 100 million people into the shortage of water and food.

According to Climate Central, the El Nino phenomenon is noticeable because it shifts some warm water from the west to the tropical regions in the central and eastern Pacific. This shift changes where heat is absorbed into the tropical atmosphere, affecting air circulation patterns. Due to the domino effect , acting on a global spread, climate change is located tens of thousands of kilometers away.

Two main air circulation models influenced by El Nino are Walker Circulation and Hadley Circulation.Walker Circulation is a model of air masses moving up and down like a vertical spiral. The mass of air moving upward corresponds to unstable precipitation climates, while the downward air mass creates a dry and stable weather.

The largest herd of sheep in Vietnam in Ninh Thuan is at risk of starvation due to prolonged drought.(Photo: Vietmaz.)

Normally, in the tropical Pacific region, the upward air mass is in the west, where the sea is warmest. Under the eastward movement of El Nino, both the upward and downward air masses pull to the east bank, leading to a wetter climate in areas that are dry and vice versa.

The change in the Walker Circulation model caused a different model called Hadley Circulation (north to south) to change, affecting the subtropical wind, the area of ​​fast-moving air that led to storms in both the Northern Hemisphere and the Southern Hemisphere.

Indonesia in particular and Southeast Asia are generally one of the areas directly affected by the El Nino phenomenon. The shift of the Walker Circulation model means that the air masses are upward and the climate is heavily dragged to the east, causing Indonesia to become dry for most of the year. Drought causes a shortage of water , crop failure and livestock and crops withered. Consequently, people fall into food shortages , rising food prices and a large risk of fire .

This year, severe drought also occurred in Vietnam, Thailand, the Philippines and some Pacific islands. Especially in Vietnam, droughts lead to mangrove problems in the Mekong Delta, home to 20 million people and important food stores in the country. The Republic of Marshall Islands and the Federated States of Micronesia, two island nations in the Pacific, are forced to declare a state of emergency, conduct distribution and transport water from elsewhere.