"Study Links Current Super El Niño to Rising Heat Deaths"
ENSO
El Niño-Southern Oscillation, the periodic warming and cooling cycle of the tropical Pacific Ocean.
Niño 3.4 Index
measure of sea-surface temperature anomaly used to gauge El Niño strength.
El Niño is the warm phase of the El Niño-Southern Oscillation (ENSO), a periodic shift in sea-surface temperature and atmospheric circulation across the tropical Pacific Ocean. Normally, trade winds push warm surface water toward Asia and Australia. During an El Niño, these winds weaken, and the warm pool shifts eastward, raising sea-surface temperatures across the central and eastern Pacific. The World Meteorological Organization tracks this shift through the Niño 3.4 Index, which measures the sea-surface temperature anomaly in a defined stretch of the central-eastern Pacific. The informal label 'Super El Niño' is used when this anomaly becomes exceptionally strong. In the current event, eastern equatorial Pacific temperatures are already more than 3°C above normal, with forecasts putting the chance of a very strong El Niño through the coming months above 90%.
El Niño's best-known effect on India is a weakening of the southwest monsoon, though this relationship is not fixed. The Indian Ocean Dipole (IOD), the sea-surface temperature difference between the western and eastern Indian Ocean, can offset or reinforce El Niño's influence on Indian rainfall in a given year. Forecasters also track Ocean Mean Temperature (OMT), measured up to the depth of the 26°C isotherm in the south-western Indian Ocean, as an early indicator of whether the coming monsoon will bring above- or below-average rainfall. This year, the southwest monsoon has entered its withdrawal phase with the national rainfall deficit at about 15% below normal, with larger shortfalls in the south and east.
Extreme heat becomes lethal through a specific physiological limit: wet-bulb temperature, which captures the combined effect of heat and humidity on the body's ability to cool itself through sweat evaporation. Once wet-bulb temperature approaches 35°C, sweat can no longer evaporate effectively, and the body's core temperature rises even in shade, regardless of hydration. This is the mechanism underlying most heat-mortality projections, including those linking the current Super El Niño to additional deaths across South and Southeast Asia, Latin America, and the Sahel.
The temperature-mortality projection method applies previously estimated relationships between heat and death rates to seasonal temperature forecasts across thousands of regions worldwide, adjusting for local climate, vulnerability, and adaptive capacity rather than relying on a single global coefficient. …
The World Bank warned that India could become one of the first places where wet-bulb temperatures routinely exceed 35°C. Which of the following statements best reflect(s) the implication of the above-said report?
I.Peninsular India will most likely suffer from flooding, tropical cyclones and droughts.
II.The survival of animals including humans will be affected as shedding of their body heat through perspiration becomes difficult.
Select the correct answer using the code given below.
With reference to Ocean Mean Temperature (OMT), which of the following statements is/are correct?
1.OMT is measured up to a depth of 26°C isotherm which is 129 metres in the south-western Indian Ocean during January-March.
2.OMT collected during January-March can be used in assessing whether the amount of rainfall in monsoon will be less or more than a certain long-term mean.
Which of the statements given above is/are correct?
With reference to 'Indian Ocean Dipole (IOD)' sometimes mentioned in the news while forecasting Indian monsoon, which of the following statements is/are correct?
1.IOD phenomenon is characterised by a difference in sea surface temperature between tropical Western Indian Ocean and tropical Eastern Pacific Ocean.
2.An IOD phenomenon can influence an El Nino's impact on the monsoon.
Select the correct answer using the code given below:
The World Bank warned that India could become one of the first places where wet-bulb temperatures routinely exceed 35°C. Which of the following statements best reflect(s) the implication of the above-said report?
I.Peninsular India will most likely suffer from flooding, tropical cyclones and droughts.
II.The survival of animals including humans will be affected as shedding of their body heat through perspiration becomes difficult.
Select the correct answer using the code given below.
Match List I (Term) with List II (What it measures) and select the correct answer using the code given below: List I:
A.Niño 3.4 Index;
B.Indian Ocean Dipole;
C.Ocean Mean Temperature (OMT);
D.Wet-bulb temperature. List II:
1.Sea-surface temperature anomaly in the central-eastern tropical Pacific Ocean;
2.Sea-surface temperature difference between western and eastern Indian Ocean;
3.Temperature measured up to the depth of the 26°C isotherm in the south-western Indian Ocean;
4.Combined effect of heat and humidity on the body's cooling capacity.
Consider the following statements about wet-bulb temperature: 1. It measures the combined effect of heat and humidity on the human body's ability to cool itself through sweat evaporation. 2. Once wet-bulb temperature crosses about 35°C, the body loses the ability to cool itself by sweating, regardless of hydration. 3. Wet-bulb temperature is always less than or equal to the dry-bulb (ambient air) temperature. How many of the above statements are correct?
With reference to the effects of El Niño on tropical cyclone activity, consider the following statements: 1. El Niño tends to increase wind shear over the Atlantic Ocean, suppressing hurricane formation there. 2. El Niño tends to favour cyclone intensification in the eastern Pacific Ocean due to warmer sea-surface temperatures. Which of the statements given above is/are correct?
The Sahel, a region frequently cited in reports on climate vulnerability across Africa, is best described as a transitional zone between which two of the following?
With reference to the burden of heat-related mortality, consider the following statements: 1. Absolute heat-related death tolls tend to be higher in more populous countries because more people are exposed. 2. Population size alone determines the mortality burden from a heatwave. 3. Vulnerability, age structure, and adaptive capacity also influence heat-mortality risk. How many of the above statements are correct?
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