Persistent occurrence of heatwaves across certain regions or countries in the world particularly in the northern hemisphere raises some fundamental questions. What causes heatwaves and why have they become more common and intense in recent times? What would be the long term or sustainable solutions for heatwaves? Are the predictions showing linear progression of heatwaves manifestation and intensity accurate? What is the relationship between heatwaves and cities? If we accept the argument that greenhouse gases are responsible then we must ask whether or not the gases do accumulate over regions experiencing heatwaves and where the gases go when heatwaves subside.

Points to note

1) French researchers established temperatures had risen by 1.45 degrees Celsius 10 metres beneath Mt. Blanc over a period of 12 months according to a report by France 24 TV in June 2019.
2) Planet earth and the sun have a two heat sources relationship.
3) The sun’s heating effect on earth’s surface is insignificant and is not responsible for global warming.
4) Temperatures inside the planet are extremely hot and fluctuate over time.
5) Out of the nearly 30% land cover of earth’s surface, much of the continental cover is in the northern hemisphere.
6) Persistent record-breaking warm temperatures in recent times.

What causes heatwaves?

Heatwaves are caused by intense heat coming through the crust thereby warming low atmospheric air at a time when there is little cold air descending over earth because the sun is overhead and warming upper atmospheric air. Increased heat on lower atmospheric air also results in air depression since warm air ascends faster. The ascending air increases pressure on the upper atmosphere which pressure is redirected to cooler regions where cold air descends over earth. This scenario is best represented by the figure below.

Nights are colder because the sun’s absence implies less warming of upper atmospheric air with more cold air falling over earth thereby overwhelming earth’s heat. Indoors remain warmer since air movement is limited while heat from below persists.