“It’s October! Why are we still talking about heat waves?”

Well, before you think we’re desperately holding on to summer, let me explain why.

When we had started planning the themes for this newsletter back in June, heatwaves were at the top of our list, unsurprisingly. This year alone, India experienced some of its hottest days on record, with several regions hitting temperatures well above 45°C. The health ministry confirmed over 40,000 heat strokes and at least 110 deaths between March 1 and June 18. And here’s the thing—this wasn’t an isolated event. 

Experts predict that heat waves will only intensify in the coming years, so learning from these patterns and preparing for the future is critical.

And despite the apparent end of summer, news about heat waves continues to pop up on my feed. 2 weeks ago, ANI reported that parts of Assam have seen a change in school timings due to a heatwave. This came as a response to an alert by India Meteorological Department (IMD) stating that the trend of rising temperature in the state will continue till 25^th September. And just last Saturday, some places in Andhra Pradesh reported a temperature of around 38 degrees. While this may not seem very hot objectively, atleast to us Indians, this was a deviation from the normal by a whopping 5°C.

So, maybe it’s not too late to talk about this phenomenon after all.

Now, this brings me to one of the most amusing news stories I’ve come across lately—and the lessons it holds.

In mid-summer 2024, a post by The Mirror went viral in social media: a heatwave alert was issued in the UK after temperatures hit 26°C for two consecutive days. Most of us should remember seeing the image that accompanied the post (and subsequently, the memes), of a person cooling off by a fountain, which left us wondering, as an X user aptly put, ‘how did they manage to rule India with our weather’.

As expected, there were countless comments from people used to hotter climates, especially from tropical countries, who found the UK’s heatwave threshold at 26°C laughable. After all, India faced scorching temperatures up to 52°C this year (though we don’t want to comment on the accuracy of sensors).

While we might chuckle at the comparison, it raises an interesting question: why is 26°C a heatwave in the UK when it’s considered mild, even pleasant, in India?

To answer this, let’s first clarify what a heatwave actually is.

What’s a Heatwave?

The IMD defines heatwaves as “periods of unusually high temperatures compared to what is normally expected over a region.” While this sounds straightforward, the specifics—what is considered “unusually high,” what counts as “normal,” and how we define a “region”—can vary widely.

Most countries base their heatwave thresholds based on the region’s average temperatures. In India, for instance, a heatwave is declared if temperature exceeds 4.5°C or more above the norm, with an actual maximum temperature reaching 45°C or more for at least two consecutive days. This also varies with geography, with thresholds of 30°C for hilly regions and 40°C for coastal regions. 

In the UK, however, the heatwave threshold is much lower, varying between 25°C and 28°C depending on the county. 

So, why does the UK struggle with 26°C when it’s a regular day in India?

There are several factors to consider.

First, UK’s infrastructure is typically designed to trap and retain heat during winters, with lots of insulation, thick materials, and very less ventilation. Most homes have no air conditioning, because in a temperate climate, it would be useless for most of the year. This makes it harder to adapt when temperatures suddenly spike, unless planning is undertaken considering the future likelihood of extreme heat events. 

Second, the UK is an island, and its high humidity levels make the heat feel a lot worse. Humidity hinders the body’s natural ability to cool down through sweating. This is also why coastal regions in India have lower heatwave thresholds. It’s not just the temperature—it’s the combination of heat and humidity that creates unbearable conditions. So even if two regions experience the same air temperature, the one with higher humidity will suffer more. 

Lastly, there’s the issue of adaptability. In India, we’re used to dealing with the heat. Simple strategies like wearing light coloured clothing, staying indoors or seeking shade during peak hours, and closing the windows during the day, have been drilled into us since childhood. However, in countries like the UK and Switzerland, heat is such a rare occurrence that people may not know how to handle it.

So, while we might laugh at a 26°C heatwave, it highlights an important point: the impacts of heatwaves—and climate change more broadly—are highly context-specific. What feels unbearable in one region might seem mild elsewhere, but that doesn’t make it any less dangerous.

So, whether it’s 26°C in the UK or 52°C in India, the real question we should be asking is: are we equipped to handle the heatwaves of tomorrow? If not, it’s high time we start preparing.

Ending with a slightly ominous thought from an article I came across:

“While this summer is likely to be one of the hottest on record, it is important to realize that it may also be one of the coldest summers of the future”.