Heat Dome


    In News

    Huge tracts of North America are sweltering under very high temperatures, which are close to 50ºC in some places. The phenomenon behind this weather is known as a ‘heat dome’.

    Heat Dome

    • It is a mountain of warm air built into a very wavy jet stream, with extreme undulations.
    • As per the National Oceanic and Atmospheric Administration (NOAA), a heat dome occurs when the atmosphere traps hot ocean air like a lid or a cap.
    • Cause: 
      • The phenomenon of Heat dome starts when there is a strong change (or gradient) in the ocean temperatures. 
      • In the process called convection, the gradient causes more warm air, heated by the ocean surface, to rise over the ocean surface.
      • The prevailing winds move the hot air east, the northern shifts of the jet stream trap the air and move it toward the land, where it sinks and results in heatwaves.
    • 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 degrees Celsius.
    • Heat Waves:
      • It is a period of unusually hot weather that lasts for more than two days.
      • The heatwaves 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.

    Image Courtesy: Barron

    Impact of Climate Change

    • Some scientists believe that the heat waves occurring today are more likely to be a result of climate change for which humans are responsible.
    • 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 the late century.

    Effects of Extreme Heat Conditions

    • Health: One of the biggest health risks in a heatwave such as this one is heatstroke.  heatstroke can lead to many serious problems including damage to the brain, heart, muscles and internal organs.
      • Older people are more susceptible to heatstroke, as the body’s ability to regulate heat deteriorates with age.
    • Agriculture: It can also have a severe impact on agriculture and forests.
      • It either causes vegetables to wilt and die or encourage the spread of plant diseases.
    • Environment: The severe heat waves cause wildfires which lead to forest cover reduction and death of fauna.
    • Infrastructure: It affects infrastructure too by straining power grids and causing blackouts. It can ground planes, melt roads and cause the inside of vehicles to overheat to dangerous levels.

    Source: IE