Delhi's 52.9 to Iran's 66 degrees Celsius: Heatwaves are breaking records globally

In July 2022, the United Kingdom surpassed 40 degrees Celsius for the first time. A small town in northwest China recorded 52 degrees Celsius last year, the highest ever for that country

The exceptionally high temperatures recorded in New Delhi over the past couple of days are remarkable but not unprecedented. In recent years, the world has seen numerous extreme weather events that highlight the escalating severity of climate change. 

Delhi is now among the regions experiencing record-breaking temperatures, often exceeding 50 degrees Celsius. On Wednesday (May 29), temperature in parts of Delhi reportedly reached 52.9 degrees Celsius, marking the highest ever recorded in India.

However, Delhi isn’t alone in facing extreme heat. In July 2022, the United Kingdom witnessed temperatures surpassing 40 degrees Celsius for the first time. A small town in northwest China recorded 52 degrees Celsius last year, the highest ever for the country. In 2021, Sicily in Italy recorded 48.8 degrees Celsius, the highest ever for Europe. 

Another alarming incident was reported from Iran last year, where the heat index caused temperatures to soar to an unprecedented 66 degrees Celsius in July. Due to this “unprecedented heat”, Iran declared public holidays and advised the elderly and those with health conditions to stay indoors.

What is the ‘feels-like’ temperature?

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 hinder 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 the human body can endure for extended periods.

What are the health risks of high temperature?

Extreme heat can have a devastating impact on human health. According to vaccine alliance GAVI, it can lead to dehydration. If a person doesn’t drink enough water to replace what is lost through sweating and urination, the blood starts to thicken, increasing the risk of heart attack and stroke.

Exposure to high temperatures can also exacerbate existing health problems, putting older people and those with chronic conditions at particularly high risk.

Are these a result of climate change?

The year 2024 was forecasted to be exceptionally warm. Last year set a record as the warmest year globally, a trend expected to continue this year—and it has not failed. Climate change has emerged as a critical global issue, with rising temperatures being a major consequence. The Earth’s climate is experiencing unprecedented changes mainly due to human activities, especially the emission of greenhouse gases into the atmosphere.

Activities like burning fossil fuels, deforestation, industrial processes, and agricultural practices have led to the accumulation of greenhouse gases such as carbon dioxide and methane. This accumulation creates a greenhouse effect, trapping heat in the Earth’s atmosphere and causing a steady rise in the planet's average temperature over the past century.

Climate change disrupts traditional weather patterns, leading to more frequent and intense heatwaves, prolonged droughts, and other extreme weather events. As temperatures rise, phenomena such as melting ice caps and increased evaporation further exacerbate warming, creating a feedback loop that intensifies climate impacts.

An analysis by Carbon Brief, a UK-based publication focused on climate change, indicated that nearly 40 per cent of the Earth recorded its highest-ever daily temperatures between 2013 and 2023, including places in Antarctica.

India still below average global temperatures

April 2024 marked the 11th consecutive month where the global average monthly temperature reached a new record, according to the European Union’s agency Copernicus Climate Change Service. The period from May 2023 to April 2024 was the warmest 12-month span on record, about 1.61 degrees Celsius higher than the pre-industrial (1850-1900) average.

However, the warming over India is less pronounced than the global average. Annual mean temperatures in India have risen by about 0.7 degrees Celsius since 1900, significantly lower than the 1.59 degrees Celsius increase in global land temperatures. Including oceans, global temperatures are currently at least 1.1 degrees Celsius higher than pre-industrial averages.

Nevertheless, heatwaves in India are becoming increasingly severe. In 2023, heatwave conditions were observed even in February, a winter month typically not associated with such conditions. 

The current high temperatures in Delhi and most of North India appear anomalous compared to the normal temperatures based on the 1981-2010 averages. Moving forward, temperatures exceeding 45 degrees Celsius are likely to become the new normal, and readings of 50 degrees Celsius will no longer seem unusual.