CLIMATE: COULD 50°C BECOME THE NEW NORMAL?

A recent heatwave in Jacobabad, Pakistan saw temperatures hit a record 51°C - dangerously close to the limit of human survivability

- PROF DANN MITCHELL

More and more heatwave records are shattered every year. Last month, we saw temperatures max out at around 51°C in central Pakistan, while last year saw a nearly 5°C toppling of the previous temperature record in western Canada. For some of India's current heatwaves, we have estimated that climate change has made them 100 times more likely, and by the end of the century, we predict that heatwave temperatures of 50°C will be an annual occurrence in the region. The numbers vary depending where you are on the globe, but one thing we can be sure about: more extremes are coming.

The feeling of being hot or cold doesn't simply depend on temperature, but a range of weather conditions. Humidity, wind speed, and solar radiation can all add or subtract from our perceived temperature, and in certain combinations, they can be deadly.

WET BULB, DRY BULB

At the heart of this combination is 'dry-bulb temperature'. This is what we normally think of when we say temperature, and what you would measure if you stuck a thermometer above your head and read off the mercury. But meteorologists often prefer to use a 'felt temperature', known as wet-bulb temperature, which is also measured with a thermometer but wrapped in a wet cloth, to mimic many of the same heat transfers that are regulated by our bodies.