Environmental

Dewan Musa

_El Nino is one of the worse effective climate patterns which helps create several natural disasters on Earth. Every two to five years, El Nino reappears and lasts for several months or even a few years. It is a regularly occurring climatic feature of Earth.

According to data provided by the US Climate Monitoring Agency, another El Niño is in progress which is likely to last from January to March 2024. El Nino has the ability to affect weather around the world.

There is a greater than 95% chance that the ongoing El Niño will continue through the Northern Hemisphere winter from January to March 2024, with the effects likely to be severe, according to a US government forecaster.

What is El Nino

El Niño is an increase in sea surface temperatures in the eastern and central Pacific, and can cause a variety of extreme weather events, from wildfires to tropical cyclones and even prolonged droughts. The warm water that causes El Niño is usually located near Indonesia during non-El Niño years. During El Nino, water moves eastward along the coast of South America.

When high sea surface temperatures in the eastern Pacific Ocean off the coast of South America are unusually warm for five consecutive months, this condition is considered an El Niño.

El Nino's influence causes global climate change by increasing the average sea surface water temperature in the region, and causing heavy rainfall along the west coast of North America and South America near the Pacific Ocean.

In July this year, the World Meteorological Organization warned that temperatures could rise further in large parts of the world after El Nino emerged in the tropical Pacific for the first time in seven years.

Effects

In 1965–1966, 1982–1983, and 1997–1998, El Nino caused significant flooding and damage from California to Mexico and Chile. This effect is felt as far away from the Pacific as in East Africa, where low rainfall often reduces the flow of the Nile.

South Americans have witnessed the effects of El Niño for hundreds of years. Climate change could make these El Niño and La Niña effects stronger and more widespread.

Areas of southern hemisphere crops affected by the ongoing El Niño are likely to suffer major losses in the coming growing season, including South Africa, Southeast Asia, Australia and Brazil, where conditions are generally drier and warmer than normal.

During El Nino, the southern part of the United States has experienced cooler and wetter weather, while the western part and parts of Canada are warmer and drier. Tropical cyclone activity generally decreases in the Atlantic, and Pacific tropical cyclones increase.

The Australian Bureau of Meteorology said El Nino indicators had strengthened earlier and a weather extreme could begin between September and November, bringing hotter and drier conditions to Australia.

The impact of El Niño weather has a huge potential for direct or indirect socio-economic losses. It has another effect which is caused by excess heat at the surface of the tropical Pacific Ocean, producing large amounts of energy in the atmosphere that can temporarily increase global temperatures.

A similar type of El Niño was identified in the early 1900s called the 'Southern Oscillation'. Later, however, the two types were considered almost the same process, and so El Niño is sometimes referred to as the El Niño/Southern Oscillation, or ENSO.

How Does El Nino Happen

In the tropical Pacific, the consistent east-to-west winds seen over vast areas of the ocean are called 'trade winds'. These winds push warm water near the surface along their path, resulting in the accumulation of warm water in the western oceans around Asia and Australia.

At one point on the other side of the ocean around South and Central America, warm water is pushed away from the coast and replaced by colder water that moves deeper into the ocean, a process called upwelling. This creates a temperature difference across the tropical Pacific, and warm water moves to the west and cold water to the east.

The warm water also adds additional heat to the air, causing the wind speed to increase sharply, and this rising air creates an area of more unstable weather with denser clouds of precipitation.

This rising westerly wind sets up atmospheric circulation across this part of the world, with warm moist air descending on one side of the ocean and cooler dry air descending on the other. This process strengthens the easterly winds, so that this part of the world remains in a self-sustaining state until El Niño begins.

If all goes well, a tropical Pacific weather system, or a slow change in the oceans around the equator, has the potential to create a chain of events that can weaken or even reverse the normal trade winds. With weaker trade winds, there is less contact or collision of warm surface water on the western side of the ocean, and cooler water originates on the eastern side.

This tends to warm the relatively colder parts of the ocean, eliminating normal temperature differences. Lateral warm water-rich areas move away, creating associated wet and unstable weather.

As a result, precipitation patterns and large-scale wind patterns in the equatorial Pacific Ocean change. This change in winds affects life around the world through changes in temperature and precipitation.

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