BBC News

• While the record-breaking maximum recorded temperature of 52.9°C has been called into question by India’s Meteorological Department, it’s entirely possible.
• The city has been sweltering, with top temperatures ranging from 45.2°C to 49.1°C, at the limit of human endurance.
• This event follows hot on the heels of extreme heatwaves across Asia as well as the Sahel in Africa.
• There’s no guarantee these air con units will extract enough heat to effectively cool our living and working areas, and electricity networks can fail.

What does extreme heat do to people?

• If the surrounding air is hotter, the body’s efforts to cool down can do just the opposite and absorb more heat.
• This is made worse during exercise, when 80% of the energy produced by working muscles is heat.
• In public health we talk about extreme heat having a “long tail” in a statistical sense.
• Mass heat death events are a relatively new phenomena, so the detailed understanding of the physiological mechanisms is still lacking.

India: hot and humid on the campaign trail

• Wednesday’s maximum temperature ranged from 45.2°C to 49.1°C, except for Mungeshpur on Delhi’s northwest outskirts, which reported 52.9°C.
• As this was an outlier compared to other weather stations, the Department said it could be due to an error in the sensor.
• Delhi is crowded, hot and humid with limited access to air conditioning.

The message for other nations

• Australia, for example, is vulnerable to extreme heat, not just because of its hot climates but also because people acclimatise to their average local conditions.
• Tasmanians can succumb to temperatures regarded as normal for people in Broken Hill, New South Wales.
• Everyone should be familiar with the signs and symptoms of heat stress, first aid treatment and when to call an ambulance.

Climate change is here, now