I wonder what a 100 yr heat death map, worldwide, would look like. When the north has summers, we are farther away from the sun. When the south has summers, we are closer to the sun. So does Africa, Australia and SA have death heat waves? It's curious and seems to happen in the mid latitudes.
It would be difficult to compare 100 years ago, certainly for the 'developed' world as life expectancy then was around 56 and I would assume recording death by heat probably wasn't accurate but that is just a guess.
"At least 473 heat-related deaths were reported to a coroner in Australia in the 18 years from July 2000 to June 2018, 354 occurred during heatwave conditions, as defined by Nairn and Fawcett (2015) and, of these, 244 occurred within or near buildings. "
Increasingly frequent and intense heatwaves, in combination with Australia’s population growth, greater urbanisation and an aging populatio,n places an increased importance on research-based risk reduction strategies.
www.preventionweb.net
For me it is a combination of behaviour and city layout from what I have read, but I can;t really justify that position, only comes across that way with what I have found so far.
Should it be connected to air quality (on another note the 1783 eruption of Laki and the impact in Europe could be cited here?), it would be impossible to improve the situation as too many people would connect it to Green Taxes, population control or a general agenda to make people rich.