EL NINO AND MONSOON – GEOGRAPHY
News: Explained | How El Nino could impact the world's weather in 2023-24
What is in the news?
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Recently, the U.S.
National Oceanic and Atmospheric Administration (NOAA) declared that an El Nino
is now underway.
Key takeaways from the news:
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Meteorologists expect
that this El Nino, coupled with excess warming from climate change, will see
the world grapple with record-high
temperatures.
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El Nino is a natural
climate phenomenon that fuels tropical
cyclones in the Pacific and boosts rainfall and flood risk in parts of the
Americas and elsewhere.
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The US National Oceanic
and Atmospheric Administration said that the past three years have been dominated by the cooler La Nina pattern.
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The last time a strong El Nino was in full swing, in 2016,
the world saw its hottest year on record.
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But even before this El
Nino began, in May, the average global
sea surface temperature was about 0.1C (0.2F) higher than any other on record.
That could supercharge extreme weather.
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Journal Science has
reported that this El Nino could cause $
3 trillion damage.
What is El Nino?
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El Nino is a natural
climate pattern of unusually warm waters
in the eastern Pacific.
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It forms when the trade winds blowing east-to-west along
the equatorial Pacific slow down or reverse
as air pressure changes.
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Because the trade winds
affect the sun-warmed surface waters, a weakening causes these warm western
Pacific waters to slosh back into the colder central and eastern Pacific
basins.
Impacts of 2016 El Nino
event:
1. Coral bleaching:
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One
third of the corals on Australia's Great Barrier Reef died.
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In too-warm waters corals
will expel living algae, causing them to calcify and turn white.
2. Disease outbreak:
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It facilitated conditions
for transmission of diseases, resulting in an uptick in reported cases for plague and hantavirus in Colorado and New
Mexico, cholera in Tanzania, and dengue fever in Brazil and Southeast Asia,
among others.
3. Drought:
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Over 60 million people faced hunger and malnutrition in 2016 due to
drought effects influenced by ENSO, with Africa the worst hit.
4. Below average rainfall:
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During the event the
Walker circulation and associated rainfall was shifted eastwards, which meant
that a large part of the Pacific received below average rainfall.
Effects of El Nino event:
1. Lower hurricanes in Atlantic:
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Hurricane activity
falters as the storms fail to form in the Atlantic due to changes in the wind,
sparing the United States.
2. Increasing frequency of cyclones in
Pacific:
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The tropical cyclones in
the Pacific get a boost, with storms often spinning toward vulnerable islands.
3. Shifting of Subtropical jet stream:
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The El Nino event affects
the subtropical jet stream and pushes its path southward and straightening it
out into a flatter stream that delivers similar weather along the same
latitudes.
4. Weather in North America:
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During an El Nino, the
southern United States experiences cooler and wetter weather, while parts of
the U.S. West and Canada are warmer and drier.
5. South America:
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Some parts of Central and
South America experience heavy rainfall, although the Amazon rainforest tends
to suffer from drier conditions.
6. Australia:
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Australia endures extreme
heat, drought and bushfires.
7. Horn of Africa:
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El Nino brings more rain
to the Horn of Africa region, unlike the triple-dip La Nina which desiccated
the region.
El Niño impacts on India:
1. Reduced rainfall:
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El Niño typically leads
to reduced rainfall in India, especially in the central and western parts of
the country. This can cause droughts, crop failures, and water shortages.
2. Delayed monsoon onset:
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El Niño can also delay
the onset of the monsoon in India. This can be a problem for farmers, as they
need the monsoon rains to water their crops.
3. Shifted rainfall patterns:
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El Niño can also shift
the rainfall patterns in India. For example, it can cause more rain to fall in
the northeast of the country, while reducing rainfall in the southwest.
4. Increased cyclone activity:
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El Niño can also increase
the frequency and intensity of cyclones in the Indian Ocean. This can cause
flooding and damage to coastal areas.