By Vivian Olaya, June 5 2023—
El Niño, or El Niño Southern Oscillation (ENSO), is a natural climate cycle pattern that takes place in the Pacific Ocean around the equator/tropical area. It affects temperature, winds, clouds and weather around the world. The name “El Niño” means “the Christ child” and it was given by fishermen in South America when they noticed that around Christmas, when El Niño reaches its peak, the temperature of the Pacific Ocean surface turned warmer than average. El Niño causes changes in floods, droughts, heatwaves, and cold seasons for different regions.
This phenomenon happens on average every two to seven years and can last from nine to twelve months, starting during the springtime and reaching its peak in December. This phenomenon remains relevant today primarily with an increased boost in El Niño events forming in the tropical Pacific this summer which will modify global weather and accelerate climate patterns.
To describe what El Niño is, we first need to understand what happens in the Pacific Ocean around the equator/tropical region during normal conditions. The rotation of the Earth on its axis traditionally causes winds to blow towards the right (from west to east) in the northern hemisphere, and to the left (from east to west, known as the trade winds) in the southern hemisphere. These winds cause the warm seawater to move from the east towards the western Pacific. The warm water then piles up around southeast Asia in Indonesia, Malaysia and Australia.
Simultaneously, the seawater in the eastern Pacific is replaced by cold water pulled up from deeper in the ocean. As the warmer seawater piles up in the west it evaporates, causing moisture to rise into the air and form clouds, leading to more rainfalls in the Asia region. At the eastern Pacific, the cooler seawater piles up, and the area cools with drier air and doesn’t evaporate as quickly. This process is maintained throughout normal climate cycle conditions, where the east Pacific (west coast of South America) turns dry, providing a more favourable environment for fish to live in, and east Asia and Australia become wetter as a result of the warmer seawater, making it favourable for agriculture growth such as rice.
The El Niño phenomenon occurs when the strength of the Pacific Ocean trade winds decreases, weakening the strength to push the seawater from east to west. This results in less warm seawater shifting towards the west and more remaining in the eastern Pacific Ocean — west of South America. Therefore, there will be less cold ocean water pulled up from the deep at the eastern Pacific Ocean causing seawater temperatures to warm up to six degrees Celsius in South America, which isn’t an optimum environment for fish to grow. This also further leads to increased rainfalls in Peru causing floods.
At the same time, the western Pacific Ocean, with drier weather and colder seawater temperatures in Asia and Australian regions, will have a less wet environment, decreasing the good conditions for agricultural growth. As a result of the significant variation of the weather in both the western and eastern Pacific Ocean, normal economical activities like fishing on the west border of South America and agricultural growth — such as rice — in east Asia, are greatly affected.
Although El Niño changes normal weather patterns and the atmospheric circulation at the Equator region in the Pacific Ocean, it also causes a global weather impact and an increase in temperature across the world. Some impacts are seen in fishery and agricultural activity primarily in places like India, Africa and Indonesia due to drier climates increasing droughts, resulting in forest and crop fires. This can ultimately influence socioeconomic issues between and within countries with rising food prices and famine. It can also cause an increase in universal health problems such as malnutrition, disease outbreaks, heat stress, and respiratory diseases. With a rise of heat and moisture in the atmosphere, there is a reduction of hurricanes across the Atlantic Ocean, and an increase of hurricanes in the Pacific Ocean.
The effect of El Niño varies between the east and west coasts of Canada. In Eastern Canada, El Niño doesn’t have much of a significant impact, however, it could potentially lead to cooler than normal weather conditions as well as a reduction in the tropical cyclone activity in the Atlantic Ocean.
In Western Canada, the impact is much more significant. The weather turns warm and dry due to warmer temperatures in the seawater of the Pacific Ocean. El Niño causes milder and drier winters as well as warmer and drier summers and comes with higher risks of frequent wildfires, such as those currently happening in Alberta. Today, Alberta currently has more than 90 active wildfires and even though some of them may be caused by human activity, it is likely that the drier conditions, as a result of El Niño, make the areas more susceptible to lighting up. This current El Niño cycle will last up until around summer 2024, meaning that this year will likely have an increase in warmer than average temperatures in the western region of Canada.