The Financial Express

Perils of extreme heatwaves

| Updated: July 06, 2021 21:56:11

Perils of extreme heatwaves

An extreme heat wave has struck Western Canada and the US Pacific Northwest causing deaths to hundreds of people. In American Northwest, the city of Portland in the state of Oregon, for example, witnessed its highest ever temperature at 46.1 degrees Celsius on Monday last week.   Similar stories are coming from the West Coast city of Seattle in the Washington state with their attendant casualties. In British Columbia of Western Canada, on the other hand, the heat wave led to a rise in temperature that broke all previous records. At the village of Lytton in British Columbia, for example, the temperature rose to as high as 49.6 degrees Celsius (121.3 degrees Fahrenheit) triggering a wildfire that destroyed 90 per cent of the village. The British Columbia Wildfire Service reported some 78 incidents of fire in the previous weeks. In a map showing heat spots, the National Weather Service (NWS) of Portland viewed the temperatures as very uncommon. In fact, these areas never experienced such kind of extreme weather events.

But what lies behind these extreme weather phenomena? Has climate change any role to play in creating this heat wave?  But let us first try to understand what a heat wave is.

It is an excessively hot weather often accompanied by humidity. However, what is extreme heat in one region, say, Canada, may not be extreme, say, in Saudi Arabia. So, for the weather condition to be called heatwave in a particular region, the temperatures have to be above the historical average in the region in question for two or more days, before the spell of extreme heat could be called a 'heatwave' in that locality, says the US National Weather Service (NWS). Now the question, what is behind this heat wave in the American Northwest and Western Canada? Generally, when high pressure in the atmosphere builds up-a dome of pressure-in a particular region over a period of several days or weeks, it gives rise to heatwave.  And this extreme weather condition can be further worsened by human-induced climate change and thereby increase the likelihood of repeated occurrence of such extreme weather events, according to meteorologists.  The international news agency AFP, on the other hand, terms the phenomenon causing this 'one of the most extreme heat waves that we have seen on earth' a 'heat dome'. And the heat dome, according to AFP, is when 'hot air is trapped by high pressure fronts, and as it is pushed back to the ground, it heats up even more'. It is like compressed air heating up when pumped into a bicycle tire. And the condition called 'heat dome' prevents clouds from forming causing sun rays to make the ground hotter.

The recurrence of the extreme heat wave over the past couple of decades in Europe and North America, regions of cold climate, has made it clear that no regions of earth is immune from this extreme weather condition. Heat waves' global spread points strongly to their link to global warming. So, the world will have to brace for more of such extreme weather events everywhere and should be prepared to take measures to cope with them. So, it is important to know what happens to a human body when hit by an extreme heatwave and learn to protect it.  Everyone knows that in a very hot weather the body tries to cool itself through sweating profusely. It causes dehydration, a condition that can be counterbalanced by drinking a lot of water. Otherwise, the blood will thicken developing clots, which may prove to be deadly. Old people are especially at risk in such condition.

Other forms of heat-related complications include: exhaustion, fainting, heatstroke, etc.  In the case of heatstroke, body's internal mechanism of balancing heat received through losing heat fails. When this heat regulatory system fails, the internal temperature rises causing heatstroke. To avoid this syndrome, body surface needs to be kept cool by diving in cold water, getting shower, using fan or air cooler, etc.

People of this part of the world have a natural advantage against the perils of heatwave. But that should not be an excuse to be complacent. Everyone needs to learn how to cope in the face of extreme heatwave.

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