COVID-19 Pandemic ???

The COVID-19 pandemic, also known as the coronavirus pandemic, is an
ongoing pandemic of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The disease was first identified in December 2019 in Wuhan, China, became a Public Health Emergency of International Concern in January 2020, and subsequently recognised as a pandemic in March 2020. As of 2 October 2020, more than 34.3 million cases have been reported worldwide, although the true number of cases are likely to be more higher. A more reliable indicator for case spread is the more than 1.02 million deaths attributed to COVID-19. Many recoveries from confirmed infections go unreported, but at least 23,711,591 people have recovered from confirmed infections.

The disease spreads between people most often when they are physically close. It spreads very easily and sustainably through the air, primarily via small droplets or particles such as aerosols, produced after an infected person breathes, coughs, sneezes, talks or sings. It may also be transmitted via contaminated surfaces, although this has not been conclusively demonstrated. It can spread for up to two days prior to symptom onset and from people who are asymptomatic. People remain infectious for 7–12 days in moderate cases and up to two weeks in severe cases. 

Longer-term damage to organs (in particular lungs and heart) has been observed, and there is concern about a significant number of patients who have recovered from the acute phase of the disease but continue to experience a range of effects including severe fatigue, memory loss and other cognitive issues, low grade fever, muscle weakness, breathlessness and other symptoms for months afterwards

Common symptoms include fever, cough, fatigue, shortness of breath or breathing difficulties, and loss of smell.

Complications may include pneumonia and acute respiratory distress syndrome. The incubation period is typically around five days but may range from one to 14 days. There are several vaccine candidates in development, although none have completed clinical trials to prove their safety and efficacy. There is no known specific antiviral medication, so primary treatment is currently symptomatic.

Recommended preventive measures include hand washing, covering mouth when sneezing or

coughing, social distancing, wearing a face mask in public, disinfecting surfaces, ventilating and air-filtering, and monitoring and self-isolation for people who suspect they may be infected. Authorities worldwide have responded by implementing travel restrictions, lockdowns, workplace hazard controls, and facility closures to slow the spread of the disease. Many places have also worked to increase testing capacity and trace contacts of the infected.

The pandemic has caused global social and economic disruption, including the largest global recession since the Great Depression. According to estimations, up to

100 million people have fallen into extreme poverty and global famines are affecting 130 million people. It has led to the postponement or cancellation of sporting, religious, political, and cultural events, widespread supply shortages exacerbated by panic buying, and decreased emissions of pollutants and greenhouse gases. Educational institutions have been partially or fully closed, with many switching to online schooling. Later in the pandemic certain countries reopened schools, usually with heavy restrictions and higher funding. Misinformation about the virus has circulated through social media and mass media. There have been many incidents of xenophobia and racism against Chinese people and against those perceived as being Chinese or as being from areas with high infection rates. The general public often call "coronavirus" both the virus and the disease it causes. U.S. President Donald Trump referred to the virus as the "Chinese virus" in tweets, interviews, and White House press briefings, which drew some criticism that he was stigmatizing the disease with racial or nationalistic overtones.

Virology

Infection and transmission

Human-to-human transmission of SARS-CoV-2 was confirmed on 20 January 2020, during the COVID-19 pandemic. Transmission was initially assumed to occur primarily via respiratory droplets from coughs

and sneezes within a range of about 1.8 metres (6 ft). Laser light scattering experiments suggest speaking as an additional mode of transmission. Other studies have suggested that the virus may be airborne as well, with aerosols potentially being able to transmit the virus.

Indirect contact via contaminated surfaces is another possible cause of infection. Preliminary research indicates that the virus may remain viable on

plastic (polypropylene) and stainless steel (AISI 304) for up to three days, but does not survive on cardboard for more than one day or on copper for more than four hours; the virus is inactivated by soap, which destabilises its lipid bilayer. Viral RNA has also been found in stool samples and semen from infected individuals.

Prevention and treatment

There are no vaccines or antiviral drugs to prevent or treat human coronavirus infections. Treatment is only supportive. A number of antiviral targets have been identified such as viral proteases, polymerases, and entry proteins. Drugs are in development which target these proteins and the different steps of viral replication. A number of vaccines using different methods are also under development for different human coronaviruses.

There are no antiviral drugs to treat animal coronaviruses. Vaccines are available for IBV, TGEV, and Canine CoV, although their effectiveness is limited. In the case of outbreaks of highly contagious animal coronaviruses, such as PEDV, measures such as destruction of entire herds of pigs may be used to prevent transmission to other herds.

Swine influenza and respiratory disease

Swine influenza (also known as swine flu or pig flu) is a respiratory disease that occurs in pigs that is caused by the Influenza A virus. Influenza viruses that are normally found in swine are known as swine influenza viruses (SIVs). The known SIV strains include influenza C and the subtypes of influenza A known as H1N1, H1N2, H3N1, H3N2 and H2N3. Pigs can also become infected with the H4N6, H9N2 subtypes and ASF (African Swine Fever)

Swine influenza virus is common throughout pig populations worldwide. Transmission of the virus from pigs to humans is not common and does not always lead to human influenza, often resulting only in the production of antibodies in the blood. If transmission does cause human influenza, it is called zoonotic swine flu or a variant virus. People with regular exposure to pigs are at increased risk of swine flu infection. Properly cooking the meat of an infected animal removes the risk of infection.

Pigs experimentally infected with the strain of swine flu that caused the human pandemic of 2009–10 showed clinical signs of flu within four days, and the virus spread to other uninfected pigs housed with the infected ones.

With around 1 billion individuals alive at any time, the domestic pig is one of the most numerous large mammals on the planet.

Feral pigs like other introduced mammals are major drivers of extinction and ecosystem change.

They have been introduced into many parts of the world, and will damage crops and home gardens as well as potentially spreading disease. They uproot large areas of land, eliminating native vegetation and spreading weeds. This results in habitat alteration, a change in plant succession and composition and a decrease in native fauna dependent on the original habitat.

Pigs and food safety

The pandemic virus is a type of swine influenza, derived originally from a strain which lived in pigs, and this

origin gave rise to the common name of "swine flu". This term is widely used by mass media, though the Paris-based World Organisation for Animal Health as well as industry groups such as the U.S. National Pork Board, the American Meat Institute, and the Canadian Pork Council objected to widespread media use of the name "swine flu" and suggested it should be called "North American flu" instead, while the World Health Organization switched its designation from "swine influenza" to "influenza A (H1N1)" in late April 2009. The virus has been found in U.S. hogs, and Canadian as well as in hogs in Northern Ireland, Argentina, and Norway. Leading health agencies and the United States Secretary of Agriculture have stressed that eating properly cooked pork or other food products derived from pigs will not cause flu.

 

Deforestation

Kate Jones, chair of ecology and biodiversity at University College London, says zoonotic diseases are Increasingly linked to environmental change and human behaviour. The disruption of pristine

forests driven by logging, mining, road building through remote places, rapid urbanisation and population growth is bringing people into closer contact with animal species they may never have been near before. The resulting transmission of disease from wildlife to humans, she says, is now “a hidden cost of human economic development". In a guest article published by IPBES, Peter Daszak and three co-chairs of the 2019 Global Assessment Report on Biodiversity and Ecosystem Services, Josef Settele, Sandra Díaz and Eduardo Brondizio, write that "rampant deforestation, uncontrolled expansion of agriculture, intensive farming, mining and infrastructure development, as well as the exploitation of wild species have created a ‘perfect storm’ for the spillover of diseases from wildlife to people. Deforestation, wildlife farming and trade in unsanitary conditions increases the risk of new zoonotic diseases, biodiversity experts have warned.

Misinformation related to the COVID-19 pandemic

The COVID-19 pandemic has resulted in misinformation and conspiracy theories about the scale of the pandemic and the origin, prevention, diagnosis, and treatment of the disease. False information, including intentional disinformation, has been spread through social media, text messaging, and mass media, including the tabloid media, conservative media, and state media of countries such as China, Russia, Iran, and Turkmenistan. It has also been reportedly spread by covert operations backed by states such as Saudi Arabia, Russia and China to generate panic and sow distrust in other countries. In some countries, such as India, Bangladesh, and Ethiopia, journalists have been arrested for allegedly spreading fake news about the pandemic.

Misinformation has been propagated by celebrities, politicians (including heads of state in countries such as the United States, Iran, and Brazil), and other prominent public figures. Commercial scams have claimed to offer at-home tests, supposed preventives, and "miracle" cures. Several religious groups have claimed their faith will protect them from the virus. Some people have claimed the virus is a bioweapon 

accidentally or purposefully leaked from a laboratory, a population control scheme, the result of a spy operation, or the side effect of 5G upgrades to cellular networks.

The World Health Organization has declared an "infodemic" of incorrect information about the virus, which poses risks to global health.

Lodestone

A lodestone is a naturally magnetized piece of the mineral magnetite. They are naturally-occurring magnets, which can attract iron. The property of magnetism was first discovered in antiquity through magnetic compasses, and their importance to early navigation is indicated by the name lodestone, which in Middle English means 'course stone' or 'leading stone', from the now-obsolete meaning of lode as ‘journey, way’.
lodestones. Pieces of lodestone, suspended so they could turn, were the first
Lodestone is one of the few minerals that is found naturally magnetized. Magnetite is black or brownish-black, with a metallic luster, a Mohs hardness of 5.5–6.5 and a black streak.

Origin

The process by which lodestone is created has long been an open question in geology. Only a small amount of the magnetite on Earth is found magnetized as lodestone. Ordinary magnetite is attracted to a magnetic field like iron and steel is, but does not tend to become magnetized itself; it has too low a magnetic coercivity (resistance to demagnetization) to stay magnetized for long.

Microscopic examination of lodestones has found them to be made of magnetite (Fe₃O₄) with inclusions of maghemite (cubic Fe₂O₃), often with impurity metal ions of titanium, aluminium, and manganese. This inhomogeneous crystalline structure gives this variety of magnetite sufficient coercivity to remain magnetized and thus be a permanent magnet.
The other question is how lodestones get magnetized. The Earth's magnetic field at 0.5 gauss is too weak to magnetize a lodestone by itself. The leading theory is that lodestones are magnetized by the strong magnetic fields surrounding lightning bolts. This is supported by the observation that they are mostly found near the surface of the Earth, rather than buried at great depth.

Properties
Lodestones were used as an early form of magnetic compass. Magnetite typically carries the

dominant magnetic signature in rocks, and so it has been a critical tool in paleomagnetism, a science important in understanding plate tectonics and as historic data for magnetohydrodynamics and other scientific fields. The relationships between magnetite and other iron-rich oxide minerals such as ilmenite, hematite, and ulvospinel have been much studied; the reactions between these minerals and oxygen influence how and when magnetite preserves a record of the Earth's magnetic field.
Magnetite has been very important in understanding the conditions under which rocks form.

Magnetite reacts with oxygen to produce hematite, and the mineral pair forms a buffer that can control oxygen fugacity. Commonly, igneous rocks contain grains of two solid solutions, one of magnetite and ulvospinel and the other of ilmenite and hematite. Compositions of the mineral pairs are used to calculate how oxidizing was the magma (i.e., the oxygen fugacity of the magma): a range of oxidizing conditions are found in magmas and the oxidation state helps to determine how the magmas might evolve by fractional crystallization.
Magnetite also occurs in many sedimentary rocks, including banded iron formations. In many igneous rocks, magnetite-rich and ilmenite-rich grains occur that precipitated together in magma. Magnetite also is produced from peridotites and dunites by serpentinization.
The Curie temperature of magnetite is 858 K (585 °C; 1,085 °F).

Applications
1) Magnetic recording
Audio recording using

magnetic acetate tape was developed in the 1930s. The German magnetophon utilized magnetite powder as the recording medium. Following World War II the 3M company continued work on the German design. In 1946 the 3M researchers found they could improve the magnetite based tape, which utilized powders of cubic crystals, by replacing the magnetite with needle shaped particles of gamma ferric oxide (γ-Fe₂O₃).

2)  Catalysis
Magnetite is the catalyst for the industrial synthesis of ammonia

3)  Arsenic sorbent
Magnetite powder efficiently removes arsenic(III) and arsenic(V) from water, the efficiency of which increases ~200 times when the magnetite particle size decreases from 300 to 12 nm. Arsenic-contaminated drinking water is a major problem around the world, which can be solved using magnetite as a sorbent.

4)  Other
Because of its stability at high temperatures, it is used for coating industrial watertube steam boilers. The magnetite layer is formed after a chemical treatment (e.g. by using hydrazine).
Iron-metabolizing bacteria can trigger redox reactions in microscopic magnetite particles. Using light, magnetite can reduce chromium (VI) (its toxic form), converting it to less toxic chromium (III), which can then be incorporated into a harmless magnetite crystal. Phototrophic Rhodopseudomonas palustris oxidized the magnetite, while Geobacter sulfurreducens reduced it, readying it for another cycle.

Pyrogen (fever)

Fever, also known as pyrexia and febrile response, is defined as having a temperature above the normal range due to an increase in the body's temperature set-point. There is not a single agreed-upon upper limit for normal temperature with sources using values between 37.5 and 38.3 °C (99.5 and 100.9 °F). The increase in set-point triggers increased muscle contraction and causes a feeling of cold. This results in greater heat production and efforts to conserve heat. When the set-point temperature returns to normal a person feels hot, becomes flushed, and may begin to sweat. Rarely a fever may trigger a febrile seizure. This is more common in young children. Fevers do not typically go higher than 41 to 42 °C (105.8 to 107.6 °F).
A fever can be caused by many medical conditions ranging from the not serious to potentially viral, bacterial and parasitic infections such as the common cold, urinary tract infections, meningitis, malaria and appendicitis among others. Non-infectious causes include vasculitis, deep vein thrombosis, side effects of medication, and cancer among others. It differs from hyperthermia, in that hyperthermia is an increase in body temperature over the temperature set-point, due to either too much heat production or not enough heat loss.

serious. This includes Treatment to reduce fever is generally not required. Treatment of associated pain and inflammation, however, may be useful and help a person rest. Medications such as ibuprofen or paracetamol may help with this as well as lower temperature. Measures such as putting a cool damp cloth on the forehead and having a slightly warm bath are not useful and may simply make a person more uncomfortable. Children younger than three months, people with serious medical problems such as a compromised immune system, and people with other symptoms may require medical attention. Hyperthermia does require treatment.
Fever is one of the most common medical signs. It is part of about 30% of healthcare visits by children and occurs in up to 75% of adults who are seriously sick. While fever is a useful defense mechanism, treating fever does not appear to worsen outcomes. Fever is viewed with greater concern by parents and healthcare professionals than it usually deserves, a phenomenon known as fever phobia.

Pyrogens
A pyrogen is a substance that induces fever. These can be either internal (endogenous) or external (exogenous) to the body. The bacterial substance lipopolysaccharide (LPS), present in the cell wall of some bacteria, is an example of an exogenous pyrogen. Pyrogenicity can vary: In extreme examples, some bacterial pyrogens known as superantigens can cause rapid and dangerous fevers. Depyrogenation may be achieved through filtration, distillation, chromatography, or inactivation.

Hypothalamus
The brain ultimately orchestrates heat effector mechanisms via the autonomic nervous system. These may be:

• Increased heat production by increased muscle tone, shivering and hormones like epinephrine (adrenaline)
• Prevention of heat loss, such as vasoconstriction.

In infants, the autonomic nervous system may also activate brown adipose tissue to produce heat (non-exercise-associated thermogenesis, also known as non-shivering thermogenesis). Increased heart rate and vasoconstriction contribute to increased blood pressure in fever.

Usefulness
There are arguments for and against the usefulness of fever, and the issue is controversial. There are studies using warm-blooded vertebrates and humans in vivo, with some suggesting that they recover more rapidly from infections or critical illness due to fever. Studies suggest reduced mortality in bacterial infections when fever was present.
In theory, fever can aid in host defence. There are certainly some important immunological reactions that are sped up by temperature, and some pathogens with strict temperature preferences could be hindered.
Research has demonstrated that fever assists the healing process in several important ways:

• Increased mobility of leukocytes
• Enhanced leukocyte phagocytosis
• Endotoxin effects decreased
• Increased proliferation of T cells

Management
Fever should not necessarily be treated. Most people recover without specific medical attention. Although it is unpleasant, fever rarely rises to a dangerous level even if untreated. Damage to the brain generally does not occur until temperatures reach 42 °C (107.6 °F), and it is rare for an untreated fever to exceed 40.6 °C (105 °F).


Conservative measures

Some limited evidence supports sponging or bathing feverish children with tepid water. The use of a fan or air conditioning may somewhat reduce the temperature and increase comfort. If the temperature reaches the extremely high level of hyperpyrexia, aggressive cooling is required. In general, people are advised to keep adequately hydrated. Whether increased fluid intake improves symptoms or shortens respiratory illnesses such as the common cold is not known

Medications
Medications that lower fevers are called antipyretics. The antipyretic ibuprofen is effective in reducing fevers in children. It is more effective than acetaminophen (paracetamol) in children.

Ibuprofen and acetaminophen may be safely used together in children with fevers. The efficacy of acetaminophen by itself in children with fevers has been questioned. Ibuprofen is also superior to aspirin in children with fevers. Additionally, aspirin is not recommended in children and young adults (those under the age of 16 or 19 depending on the country) due to the risk of Reye's syndrome.
Using both paracetamol and ibuprofen at the same time or alternating between the two is more effective at decreasing fever than using only paracetamol or ibuprofen. It is not clear if it increases child comfort. Response or nonresponse to medications does not predict whether or not a child has a serious illness  

Automatic fire suppression

Automatic fire suppression systems control and extinguish fires without human intervention. fire sprinkler system, gaseous fire suppression, and condensed aerosol fire suppression.

Examples of automatic systems include
The first fire extinguisher patent was issued to Alanson Crane of Virginia on Feb. 10, 1863. The first fire sprinkler system was patented by H.W. Pratt in 1872. But the first practical automatic sprinkler system was invented in 1874 by Henry S. Parmalee of New Haven, CT. He installed the system in a piano factory he owned.

Types of automatic systems
Today there are numerous types of Automatic Fire Suppression Systems. Systems are as diverse as the many applications. In general, however, Automatic Fire Suppression Systems fall into two categories: engineered and pre-engineered systems.

Engineered Fire Suppression Systems are design specific. Engineered systems are usually for
larger installations where the system is designed for the particular application. Examples include marine and land vehicle applications, computer clean rooms, public and private buildings, industrial paint lines, dip tanks and electrical switch rooms. Engineered systems use a number of gaseous or solid agents. Many are specifically formulated. Some, such as 3M Novec 1230 Fire Protection Fluid, are stored as a liquid and discharged as a gas.

Pre-Engineered Fire Suppression Systems use pre-designed elements to eliminate the need for
potassium carbonate or monoammonium phosphate (MAP), to protect spaces such as paint rooms and surfactant additive, and target retrofit applications where the risk of fire or fire injury is high but where a conventional fire sprinkler system would be unacceptably expensive. In addition, residential range hood fire suppression systems are becoming more common in shared-use cooking spaces, such as those found in assisted living facilities, hospice homes, and group homes.
booths, storage areas and commercial kitchens. A small number of residential designs have also emerged that typically employ water mist with or without a engineering work beyond the original product design. Typical industrial solutions use a simple wet or dry chemical agent, such as those found in assisted living facilities, hospice homes, and group homes.

Components
By definition, an automatic fire suppression system can operate without human intervention. To do so it must possess a means of detection, actuation and delivery.

In many systems, detection is accomplished by mechanical or electrical means. Mechanical detection uses fusible-link or thermo-bulb detectors. These detectors are designed to separate at a specific temperature and release tension on a release mechanism. Electrical detection uses heat detectors equipped with self-restoring, normally-open contacts which close when a predetermined temperature is reached. Remote and local manual operation is also possible.
Actuation usually involves either a pressurised fluid and a release valve, or in some cases an electric pump.
Delivery is accomplished by means of piping and nozzles. Nozzle design is specific to the agent used and coverage desired.

Extinguishing agents
In the early days, water was the exclusive fire suppression agent. Although still used today, water has limitations. Most notably, its liquid and conductive properties can cause as much property damage as fire itself.

Agent	Primary Ingredient	Applications
HFC 227ea (e.g.FM-200)	Heptafluoropropane	Electronics, medical equipment, production equipment, libraries, data centers, medical record rooms, server rooms, oil pumping stations, engine compartments, telecommunications rooms, switch rooms, engine and machinery spaces, pump rooms, control rooms
FK-5-1-12 (3M Novec 1230 Fire Protection Fluid)	Fluorinated Ketone	Electronics, medical equipment, production equipment, libraries, data centers, medical record rooms, server rooms, oil pumping stations, engine compartments, telecommunications rooms, switch rooms, engine and machinery spaces, pump rooms, control rooms

Health and environmental concerns
Despite their effectiveness, chemical fire extinguishing agents are not without disadvantages. In the early 20th century, carbon tetrachloride was extensively used as a dry cleaning solvent, a refrigerant and as a fire extinguishing agent. In time, it was found carbon tetrachloride could lead to severe health effects.
From the mid-1960s Halon 1301 was the industry standard for protecting high-value assets from the

threat of fire. Halon 1301 had many benefits as a fire suppression agent; it is fast-acting, safe for assets and required minimal storage space. Halon 1301's major drawbacks are that it depletes atmospheric ozone and is potentially harmful to humans.
Since 1987, some 191 nations have signed The Montreal Protocol on Substances That Deplete the Ozone Layer. The Protocol is an international treaty designed to protect the ozone layer by phasing out the production of a number of substances believed to be responsible for ozone depletion. Among these were halogenated hydrocarbons often used in fire suppression. As a result, manufacturers have focused on alternatives to Halon 1301 and Halon 1211 (halogenated hydrocarbons).
A number of countries have also taken steps to mandate the removal of installed Halon systems. Most notably these include Germany and Australia, the first two countries in the world to require this action. In both of these countries complete removal of installed Halon systems has been completed except for a very few essential-use applications. The European Union is currently undergoing a similar mandated removal of installed Halon systems.

Modern systems
Since the early 1990s manufacturers have successfully developed safe and effective Halon alternatives. These include DuPont FM-200, American Pacific’s Halotron and 3M Novec 1230 Fire Protection Fluid. Generally, the Halon replacement agents available today fall into two broad categories, in-kind (gaseous extinguishing agents) or not in-kind (alternative technologies). In-kind gaseous agents generally fall into two further categories, halocarbons and inert gases. Not in-kind alternatives include such options as water mist or the use of early warning smoke detection systems. 

El Niño

El Niño /ɛl ˈniːnjoʊ/ (Spanish pronunciation: [el ˈniɲo]) is the warm phase of the El Niño Southern Oscillation (commonly called ENSO) and is associated with a band of warm ocean water that Pacific International Date Line and 120°W), including off the Pacific coast of South America. El Niño Southern Oscillation refers to the cycle of warm and cold temperatures, as measured by sea surface temperature, SST, of the tropical central and eastern Pacific Ocean. El Niño is accompanied by high air pressure in the western Pacific and low air pressure in the eastern Pacific. The cool phase of ENSO is called "La Niña" with SST in the eastern Pacific below average and air pressures high in the eastern and low in western Pacific. The ENSO cycle, both El Niño and La Niña, causes global changes of both temperatures and rainfall. Mechanisms that cause the oscillation remain under study.
(between approximately the
develops in the central and east-central equatorial


Definition
El Niño is defined by prolonged warming in the Pacific Ocean sea surface temperatures when compared with the average value.

The U.S NOAA definition is a 3-month average warming of at least 0.5 °C (0.9 °F) in a specific area of the east-central tropical Pacific Ocean; other organizations define the term slightly differently. Typically, this anomaly happens at irregular intervals of two to seven years, and lasts nine months to two years. The average period length is five years. When this warming occurs for seven to nine months, it is classified as El Niño "conditions"; when its duration is longer, it is classified as an El Niño "episode".
The first signs of an El Niño are a weakening of the Walker circulation or trade winds and strengthening of the Hadley circulation and may include:

1. Rise in surface pressure over the Indian Ocean, Indonesia, and Australia
2. Fall in air pressure over Tahiti and the rest of the central and eastern Pacific Ocean
3. Trade winds in the south Pacific weaken or head east
4. Warm air rises near Peru, causing rain in the northern Peruvian deserts

El Niño's warm rush of nutrient-poor water heated by its eastward passage in the Equatorial Current, replaces the cold, nutrient-rich surface water of the Humboldt Current.
A recent study has appeared applying network theory to the analysis of El Niño events; the study presented evidence that the dynamics of a described "climate network" were very sensitive to such events, with many links in the network failing during the events.

Effects of ENSO warm phase (El Niño)

Economic impact
When El Niño conditions last for many months, extensive ocean warming and the reduction in easterly trade winds limits upwelling of cold nutrient-rich deep water, and its economic impact to local fishing for an international market can be serious.

More generally, El Niño can affect commodity prices and the macroeconomy of different countries. It can constrain the supply of rain-driven agricultural commodities; reduce agricultural output, construction, and services activities; create food-price and generalised inflation; and may trigger social unrest in commodity-dependent poor countries that primarily rely on imported food. A University of Cambridge Working Paper shows that while Australia, Chile, Indonesia, India, Japan, New Zealand and South Africa face a short-lived fall in economic activity in response to an El Niño shock, other countries may actually benefit from an El Niño weather shock (either directly or indirectly through positive spillovers from major trading partners), for instance, Argentina, Canada, Mexico and the United States. Furthermore, most countries experience short-run inflationary pressures following an El Niño shock, while global energy and non-fuel commodity prices increase The IMF estimates a significant El Niño can boost the GDP of the United States by about about 0.5% (due largely to lower heating bills) and reduce the GDP of Indonesia by about 1.0%.

Health and social impacts

Extreme weather conditions related to the El Niño cycle correlate with changes in the incidence of epidemic diseases.

For example, the El Niño cycle is associated with increased risks of some of the diseases transmitted by mosquitoes, such as malaria, dengue, and Rift Valley fever. Cycles of malaria in India, Venezuela, Brazil, and Colombia have now been linked to El Niño. Outbreaks of another mosquito-transmitted disease, Australian encephalitis (Murray Valley encephalitis—MVE), occur in temperate south-east Australia after heavy rainfall and flooding, which are associated with La Niña events. A severe outbreak of Rift Valley fever occurred after extreme rainfall in north-eastern Kenya and southern Somalia during the 1997–98 El Niño.
ENSO conditions have also been related to Kawasaki disease incidence in Japan and the west coast of the United States, via the linkage to tropospheric winds across the north Pacific Ocean.
ENSO may be linked to civil conflicts. Scientists at The Earth Institute of Columbia University, having analyzed data from 1950 to 2004, suggest ENSO may have had a role in 21% of all civil conflicts since 1950, with the risk of annual civil conflict doubling from 3% to 6% in countries affected by ENSO during El Niño years relative to La Niña years.

Recent occurrences
Since 2000, El Niño events have been observed in 2002–03, 2004–05, 2006–07, 2009–10 and 2015–16.
In December 2014, the Japan Meteorological Agency declared the onset of El Niño conditions, as warmer than normal sea surface temperatures were measured over the Pacific, albeit citing the lack of atmospheric conditions related to the event. In March and May 2015 both NOAA's Climate Prediction Center (CPC) and the Australian Bureau of Meteorology respectively confirmed the arrival of weak El Niño conditions. El Niño conditions were forecast in July to intensify into strong conditions by fall and winter of 2015. In July the NOAA CPC expected a greater than 90% chance that El Niño would continue through the 2015-2016 winter and more than 80% chance to last into the 2016 spring. In addition to the warmer than normal waters generated by the El Niño conditions, the Pacific Decadal Oscillation was also creating persistently higher than normal sea surface temperatures in the northeastern Pacific. In August, the NOAA CPC predicted that the 2015 El Niño "could be among the strongest in the historical record dating back to 1950.” In mid November, NOAA reported that the temperature anomaly in the Niño 3.4 region for the 3 month average from August to October 2015 was the 2nd warmest on record with only 1997 warmer.

Relation to climate change
During the last several decades the number of El Niño events increased, although a much longer period of observation is needed to detect robust changes.

The question is, or was, whether this is a random fluctuation or a normal instance of variation for that phenomenon or the result of global climate changes as a result of global warming. A 2014 study reported a robust tendency to more frequent extreme El Niños, occurring in agreement with a separate recent model prediction for the future.
Several studies of historical data suggest the recent El Niño variation is linked to anthropogenic climate change; in accordance with the larger consensus on climate change. For example, even after subtracting the positive influence of decade-to-decade variation (which is shown to be present in the ENSO trend), the amplitude of the ENSO variability in the observed data still increases, by as much as 60% in the last 50 years.
It may be that the observed phenomenon of more frequent and stronger El Niño events occurs only in the initial phase of the climate change, and then (e.g., after the lower layers of the ocean get warmer, as well), El Niño will become weaker than it was. It may also be that the stabilizing and destabilizing forces influencing the phenomenon will eventually compensate for each other. More research is needed to provide a better answer to that question. However, a new 2014 model appearing in a research report indicated unmitigated climate change would particularly affect the surface waters of the eastern equatorial Pacific and possibly double extreme El Niño occurrences.