El Nino, La Nina and its Implication IAS Target

El Nino, La Nina and its Implication

31 Jul 2020

Category : Geography

Topic: El Nino, La Nina and its Implication

Monsoon is a familiar though a little known climatic phenomenon. In India, from agriculture to economic policies to disaster management, a lot depends on the Monsoon. The Monsoon is a recurring event i.e. it repeats after a certain frequency of time – a year in our case. But, it may not be uniform in every period (year). There are a lot of factors which affect its duration and intensity over India.
Monsoon where winds changes their direction twice each year, atmospheric circulation which reverses wind direction completely Every 6 months during summer and winter seasons. Wind blow from NE to SW for 6 months during winter season and from SW to NE for 6 months during summer season. The Monsoon is basically a result of the flow of moisture laden winds because of the variation of temperature across the Indian Ocean.

There are a number of climatic phenomena which affect it namely:
  • The Indian ocean dipole,
  • El nino,
  • La nina,
  • Equatorial Indian Ocean Oscillation (EQUINOO) etc.
These phenomena affect the temperature distribution over the oceans and thus affecting the direction and intensity of flow of the moisture laden winds. There have been recent reports that El Nino may disturb the Indian Monsoon and play badly with Indian agriculture. This brings us to the discussion of the concepts of El Nino and La Nina. In what follows we will look at their origin, mechanism, impact and mitigation strategies.

Origin

A sub-surface warm current, known as El-Nino current flows from north to south b/w 3° S to 36° S latitudes at a distance of about 180km from the Peruvian coast. The southward shifting of the counter equatorial warm current during southern winter gives birth to El-Nino current. The temperature at Peruvian coast doesn’t fall considerably because of this current. Though the amount of rainfall increases along the coast due to this current but fishes die due to disappearance of planktons and occurance of Guano disease and pests caused by El-Nino. It may be pointed out that El-Nino also affect monsoon in the Indian ocean. When El-Nino extended to the southern end of the S-America, warm water is pushed eastward to join the south-atlantic westerlies drift which bring warm water in the south-Indian ocean during southern winters. Consequently the high pressure in the Indian ocean during southern winter is not intensified due to which the SW summer monsoon is weakened.
El-Nino is considered as a weather event or phenomenon. El-Nino has been related to the increase of temperature of the east Pacific Ocean off Peruvian coast while La-Nina is related to the warming of the western Pacific ocean. The strong El-Nino brings heavy rainfall exceeding normal rainfall resulting into lush green otherwise dry coastal land of Peru. The cold water mass near Peruvian coast becomes warm due to strong El-Nino event resulting into heavy rainfall in the 1st half of the year (Jan to march). The heavy rainfall associated with strong El-Nino even makes coastal Peruvian deserts green and there is rich harvest of cotton, coconuts and bananas but there is oceanic biological disaster. It may be maintained that in the event of strong El-Nino the tropical eastern Pacific receives 4 to 6 times more rainfall than normal amount but dry condition prevails in the tropical western pacific resulting into severe drought in Indonesia, Bangladesh, India etc.
La-Nina is a counter ocean current which becomes effective in the tropical western Pacific when El-Nino becomes ineffective in the tropical eastern Pacific. The dry condition in the western Pacific is terminated and wet condition is introduced in the tropical western Pacific by La-Nina.

La-Nina

La Nina, “anti-El Nino” or simply “a cold event” is the cooling of water in the Eastern Pacific Ocean.
The following happens in La-Nina:
  • The water in Eastern Pacific, which is otherwise cool; gets colder than normal.
  • There is no reversal of the trade winds but it causes strong high pressure over the eastern equatorial Pacific.On the other hand, low pressure is caused over Western Pacific and Off Asia.

This has so far caused the following major effects:
  • Drought in Ecuador and Peru.
  • Low temperature,
  • High Pressure in Eastern Pacific.
  • Heavy floods in Australia;
  • High Temperature in Western Pacific, Indian Ocean, Off coast Somalia and good rains in India.
  • Drought in East Africa.
For India, an El Nino is often a cause for concern because of its adverse impact on the south-west monsoon; this happened in 2009. A La Nina, on the other hand, is often beneficial for the monsoon, especially in the latter half. The La Nina that appeared in the Pacific in 2010 probably helped 2010’s south-west monsoon end on a favorable note. However, it also contributed to the deluge in Australia, which resulted in one of that country’s worst natural disasters with large parts of Queensland either under water from floods of unusual proportions or being battered by tropical cyclones.

Correlation of El-Nino, La- Nina and drought in the Indian Landscape

“Looking at the relation between El Nino and Indian droughts since 1950, it is observed that India faced 13 droughts and 10 of these were in El Nino years and one in a La Nina year. This indicates there may not be a one-to-one correspondence between El Nino and Indian droughts,” “Overall, the analysis proves that since the 1980s, only El Nino years converted into droughts for our country. However, a La Nina year does not guarantee better-than-normal rains and similarly an El Nino year does not always translate into below-normal rains,”. El Nino phenomenon may hit in the second half of the monsoon season in 2014, factors such as favourable water reservoir levels, and high stocks of grains with the government may offer relief to farmers and consumers.

Implication of El-Nino

The following are some of the effects El Nino has on the weather in this part of the world:
  • In South America, there is a drastic increase in the risk of flooding on the western coast, while there is an increase in the risk of droughts on parts of the eastern coast. In general, El Nino causes vast amounts of rainfall in the eastern parts of the Pacific (the western coast of South America), and very dry weather on the western parts (India, Indonesia).
  • With all the extra heat at the surface of the Pacific Ocean, energy is released into the atmosphere, causing an overall warming of the global climate temporarily.
  • Years in which El Nino occurs tend to feature higher temperatures across the globe.
  • The effects of El Nino on the weather peak in December and can last for several months after that.
  • After El Nino, the trade and easterly winds often fall back into their normal, self-perpetuating cycle. However, on some occasions the effect is reversed in a process called La Nina.
  • During La Nina, the trade winds are strengthened, causing the normal cycle to be more dramatic and having the reverse effect of El Nino.

Some specific and detailed information of how to prevent El Nino effects:

Food and Agriculture Of all sectors of the economy, agriculture is the one that could be severely affected by El Nino. Drought can be said as the main threat to food production, but heavy rains, flooding, and extremely hot or cold weather caused by El Nino are also pretty much as dangerous. Those things could trigger the animal disease outbreaks, like food borne diseases and zoonosis, as well as forest fires and plant pests. It has also been proven from the previous events that livelihoods that depend on fisheries have been severely affected in certain coastal areas.
This is why farmers should be planning far ahead to prepare for the worst by planting drought resistant crops that could adapt to long periods of dryness as option how to prevent el nino. Drought tolerant trees like coconut, breadfruit, and mango should grow. Since usually fruit trees fruit heavily when the climate dries even further, it would be helpful if people preserve this fruit for future use so it doesn’t go to waste. Multi-store cropping system also helps people getting through the limited rainfall days.
Health Preparations El Nino could severely affect the health of the people depends on the countermeasures. The extent of these impacts depend on the vulnerability of the populations and national capacity. Its including how the health systems of the region prepare and respond. Most diseases and deaths caused by El Nino are related to weather-related disasters such as droughts, cyclones, and floods. Outbreaks of some diseases are associated with those extreme weather events most of the time.
Droughts could cause individual heat stress which may significantly diminish hydropower capacity and may then reduce electricity available to health facilities. Cyclone activity and flooding could also cause significant loss of life and other possible health and psycho-social effects. Flooding usually trigger food insecurity which then will possibly lead to the increase malnutrition and enhance vulnerability to infectious diseases. Damaged sanitation infrastructure also increase water and vector borne infectious diseases. Poor air and water quality could also trigger new exacerbate existing physical and mental health conditions.
To prevent these negative impacts on health, health authorities in those countries should do deeper analysis of historic climate and health data of El Nino events. There should be research and climate risk assessments to provide helpful information and planning. Sub populations like aged persons, people with disability, pregnant women, children and those with chronic health conditions should be identified specifically since their health status contributes to greater health risks. They should also step up their preparedness to tend the most likely risk areas. It is important to promote dialogue with health actors, partner organizations at all levels, national meteorological agencies, and disaster management organizations
Hygienic Water There are actually some ways to cope with drought and lack of clean water caused by El Nino. In drought situations especially, people may have to travel further to access water from unfamiliar source which may also affect their safety and security. When water supply is inadequate, these activities will become also more difficult since limited water is needed for drinking and cooking.
To reduce more water consumption and wastage at the household level, people have to know their usage. Don’t forget to save more water by reusing existing water. Collect rainwater from roof gutters and reuse dishwashing, laundry, and bath water to flush the toilet and wash cars. When washing cars, use a dipper and a pail of the reused water. It is important to pay attention to children too since they are usually the biggest water users. If water plants is needed, do it in early morning or late afternoon to minimize evaporation.
Shelter Preparation Whether it is drought or cyclones, it is important to make sure the preparedness of our house. In areas of drought, it is important to have properly functioning roofs and rainwater harvesting systems which could contribute to local level resilience to El Nino by acting as a valuable source of water collection and storage.
People have to make sure their roofs are secure and free from potential water contaminants. It is important to make sure gutters are secured and still functions. If you don’t have a rainwater harvesting system, identify where water runs off your roof and consider what containers or buckets you could use to capture some water when it rains.
Evacuation Area This step has to be built between the government and the people. This could also be considered as the last thing to do when avoiding El Nino if the previous couldn’t contain the level of risk the phenomenon blast. Governments have to be communicative to the people when certain areas are in risk of getting stuck in huge storm. They have to provide people secure accommodation, in an area further inland and on higher ground.
Other than special medical needs, access to power, clean water, and oxygen, the government has to help their people with emergency kits too. The emergency kit could include dry-goods such as flour, rice, sugar, tea or powdered milk, as well as canned food and other emergency supplies.

Other Way to Prevent

  • The government must make early warning to community around to make preparations in all sectors.
  • Prepare food staples to anticipate food famine. its purposes is for prevent people starving if El Nino occurred.
  • Farmers must increase their stocks of rice and staples crops production to reach their targets.
  • Acceleration and pursuing the planting period in various regions.
  • Develop rice varieties which can be planted in every area with various water volume.
  • Use wetlands or swamp areas for other option to planting.
  • Keep ensure the warehouse or barn to remain surplus so it can be maintained.
  • Check every sectors. Such as immigration ducts, reservoirs, and also situations. As well as area works well to deal when El Nino comes.

We saw EL-Nino and its effects. it is natural phenomenon we can’t prevent it, but we can reduce it hazardous impact. So we should spread awareness and govt take steps to make administrative machinary more responsive and alert so that we prepared to face any externality arising from El-Nino