In recent years, the world has witnessed extreme weather events that underscore the growing severity of climate change. India's capital Delhi joined the list of regions that have seen record temperatures - mostly above 50 degrees Celsius. The temperature in Delhi reportedly reached 52.9 degrees Celsius, the highest ever in India. Another alarming development was reported from Iran where the heat index caused the temperature to soar to an unprecedented 66 degrees Celsius in July last year. These examples show the major shift Earth's climate is undergoing, causing concern among environmentalists.
What is heat index?
The heat index, often referred to as the "feels-like" temperature, combines air temperature and relative humidity to estimate the human-perceived temperature. High humidity levels impede the body's ability to cool itself through sweating, making the heat feel much more intense. A heat index of 66 degrees Celsius is life-threatening, exceeding the thresholds that the human body can endure for extended periods.
What about Delhi?
According to Kuldeep Srivastava, regional head of India Meteorological Department (IMD), the already high temperature in Delhi broke record because of hot winds from Rajasthan.
"Parts of Delhi are particularly susceptible to the early arrival of these hot winds, worsening the already severe weather. Areas like Mungeshpur, Narela and Najafgarh are the first to experience the full force of these hot winds," Mr Srivastava said. Mungeshpur in northwest Delhi is the place where 52.9 degrees Celsius was reportedly recorded.
Mahesh Palawat from Skymet Weather told news agency PTI that open areas with vacant land experience increased radiation, leading to exceptionally high temperatures due to direct sunlight and lack of shade.
The Iran shocker
The extraordinary temperature at Persian Gulf international airport was termed unsafe for human survival. Weather experts said the temperature reached 40 Degrees Celsius in the region, with a relative humidity of 65 per cent, according to NOAA data. This created an apparent temperature of 66.7 degrees Celsius.
Extreme heat can have devastating impact on humans. According to vaccine alliance GAVI, it leads to dehydration and if a person doesn't drink enough water to replace that lost through sweating and urination, the blood starts to thicken, making it more prone to clotting, which increases the risk of heart attack and stroke.
Exposure to high temperature can also amplify existing health problems, making older people and those with chronic conditions at particularly high risk.
The role of climate change
The extreme heatwave in Iran is symptomatic of broader climatic shifts driven by global warming. Key factors contributing to such extreme weather events include:
- Rising global temperatures: The Earth's average temperature has increased by approximately 1.2 degrees Celsius since pre-industrial times, primarily due to the accumulation of greenhouse gases like carbon dioxide and methane in the atmosphere.
- Altered weather patterns: Climate change disrupts traditional weather patterns, leading to more frequent and intense heat waves, prolonged droughts, and other extreme weather events.
- Feedback loops: As temperatures rise, phenomena such as melting ice caps and increased evaporation further exacerbate warming, creating a feedback loop that intensifies climate impacts.
Simultaneous heatwaves are also suffocating many other parts of the world. China, for example, recorded its highest-ever temperature of 52.2 degrees Celsius in Sanbo township in 2023. Reacting to these developments, Dr Akshay Deoras, from the University of Reading's meteorology department, said that Earth will become an "inferno" if the heatwaves don't spur on governments to tackle global warming.
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