Day 59 – Q.3 Discuss the causes and consequences of El Niño and La Niña, two of the most important geophysical phenomena that affect the global climate.

Discuss the causes and consequences of El Niño and La Niña, two of the most important geophysical phenomena that affect the global climate.

एल नीनो और ला नीना के कारणों और परिणामों पर चर्चा करें, ये दो सबसे महत्वपूर्ण भूभौतिकीय घटनाएं हैं जो वैश्विक जलवायु को प्रभावित करती हैं।

Approach

Candidates can start the answer with giving basic idea of El Nino and La Nina with its formation. And then simply explain what are its causes and different consequences

Introduction

El Niño and La Niña are two natural climate phenomena occurring across the tropical Pacific Ocean and influence the weather they are two opposing weather patterns that can have significant impacts on weather patterns around the world.

Body

• El Niño is caused by a warming of the surface waters in the eastern Pacific Ocean, which leads to a shift in the prevailing winds and a change in the location and strength of the jet stream.
• This can lead to increased rainfall in the western Pacific and drought in the eastern Pacific. El Niño can also result in increased storm activity in the eastern Pacific, and can have a range of impacts on weather patterns around the world, such as increased rainfall in some regions and drought in others.
• La Niña is the opposite of El Niño, and is caused by a cooling of the surface waters in the eastern Pacific Ocean. This leads to a shift in the prevailing winds and a change in the location and strength of the jet stream, which can lead to drought in the western Pacific and increased rainfall in the eastern Pacific.
• La Niña can also result in decreased storm activity in the eastern Pacific, and can have a range of impacts on weather patterns around the world, such as increased drought in some regions and increased rainfall in others.

Impact on global climate:

• During an El Niño event, the trade winds that usually blow from east to west across the Pacific weaken or even reverse. This allows warm water from the western Pacific to move eastward towards the coast of South America, leading to an increase in temperature and a shift in weather patterns.
• El Niño can result in increased rainfall in some regions, such as the southern United States, and drought in others, such as Australia and Indonesia.
• It can also lead to increased storm activity in the eastern Pacific, and can have a range of impacts on weather patterns around the world, such as increased flooding in some regions and drought in others.
• La Niña, on the other hand, is characterized by a cooling of the surface waters in the eastern Pacific Ocean, which leads to a strengthening of the trade winds and a shift in weather patterns.
• La Niña can result in increased rainfall in some regions, such as the western Pacific, and drought in others, such as the southern United States.
• It can also lead to decreased storm activity in the eastern Pacific, and can have a range of impacts on weather patterns around the world, such as increased drought in some regions and increased flooding in others.

El Nino impacts India:

• El Nino and Indian monsoons are inversely related. The most prominent droughts in India – six of them – since 1871 have been El Nino droughts, including the recent ones in 2002 and 2009
• However, not all El Nino years led to a drought in India. For instance, 1997/98 was a strong El Nino year but there was no drought (Because of IOD).
• El Nino directly impacts India’s agrarian economy as it tends to lower the production of summer crops such as rice, sugarcane, cotton, and oilseeds.

La Nina impacting India:

• Winter rainfall is less than normal in North India.
• Snowfall over Western Himalayas is less than normal.
• Winter temperatures in the plains are less than normal.

Conclusion

Both El Niño and La Niña can have significant impacts on agriculture, freshwater resources, and human settlements, as well as on the timing and distribution of plant and animal species. They can also impact the fishing and tourism industries, as well as global economy and trade.