Context: Canada is reeling under a severe heat wave, which has caused an unprecedented 195 per cent rise in sudden fatalities within the past five days.

• The abnormal heat wave caused the temperature in the country to rise to 49.5 degrees Celsius, an all-time record.
• The weather experts have blamed the heat dome effect for the sudden rise in temperature.

What is a Heat Dome?

• It is essentially a mountain of warm air built into a very wavy jet stream, with extreme undulations.
• It develops when there is a large poleward shift in the jet stream, which becomes wavy and elongated.
• The National Oceanic and Atmospheric Administration (NOAA) says that to understand what causes a heat dome, one should liken the Pacific ocean to a large swimming pool in which the heater is turned on.

The portions of the pool close to the heating jets will warm up faster once the heater is on and therefore, the temperature in that area will be higher.

• In the same way, the western Pacific Ocean’s temperatures have increased in the past few decades and are relatively more than the temperature in the eastern Pacific.
• The strong change in ocean temperature from the west to the east is what a team of scientists believe is the reason for the heat dome.
• The reason that the planet Venus is the hottest in the Solar System is because its thick, dense cloud cover traps the heat at the surface, leading to temperatures as high as 471 degree Celsius.

Effects of heat domes

• Those living without an air conditioner see the temperatures of their homes rising to unbearably high, leading to sudden fatalities like those which are being reported in Canada and parts of the US.
• The trapping of heat can also damage crops, dry out vegetation and result in droughts.
• The sweltering heat wave will also lead to rise in energy demand, especially electricity, leading to pushing up rates.
• The heat domes can also act as fuel to wildfires, which destroys a lot of land area in the US every year.

About Heat Waves

• A heat wave is a period of unusually hot weather that lasts for more than two days.
• The NWS notes that heat waves can occur with or without high humidity and have the potential to cover a large area, exposing a high number of people to hazardous heat.
• A heatwave is an extended period of hot weather relative to the expected conditions of the area at that time of year, which may be accompanied by high humidity.

Link between Heat Waves and Climate Change

• The heatwaves are extreme weather events, but research shows that climate change is making these events more likely.
• A small increase in the Earth's average temperature can dramatically impact climate extremes, both hot and cold, increasing their chances of occurring exponentially.
• The extreme heat events are occurring more frequently with more severity, and therefore they will likely push the average temperatures higher for years to come.
• If greenhouse gas emissions are not significantly curtailed, the coldest and warmest daily temperatures are expected to increase by at least 5 degrees F in most areas by mid-century rising to 10 degrees F by late century.