It's entirely certain that there are wet-bulb temperatures above which humans cannot survive for long and pretty certain that there are highly populated areas where a few more degrees warming globally means that those temperatures will be reached (or at least apprached, which is still dangerous) much more often. There are a variety of less direct potential tipping points, which may be more or less certain, but we can be quite confident that higher temperatures means more people dying in heat waves.
If you examine the IPCC report maps [1] to see what areas have the greatest heating, wet tropical areas (like India and South-East Asia) tend to have less heating (in terms of degrees) than most other places.
Some of the areas with the highest predicted temperature increases are relatively dry places, such as Siberia and several deserts.
Sure, they aren't going to be warming the most, but they have already seen an increase in the incidence of heat waves nearing or reaching unlivable temperatures in the past few decades[1] and the incidence can be expected to continue increasing as average temperatures increase.
[1] >Since 2005, wet-bulb temperature values above 95 degrees Fahrenheit have occurred for short periods of time on nine separate occasions in a few subtropical places like Pakistan and the Persian Gulf. They also appear to be becoming more frequent. In addition, incidences of slightly lower wet-bulb temperature values in the 90 to 95-degree Fahrenheit (32 to 35-degree Celsius) range have more than tripled over the 40 years studied by Raymond’s team.
If you look at excess mortality from non-optimal temperatures, instead of just people getting caught outside in bad weather, the picture changes quite dramatically, with cold killing more people per year by a factor of 4:1 or more globally, and ESPECIALLY in hot areas such as Africa and South Asia:
Furthermore, while every death to heatstroke is a tragedy, the numbers listed in the article you provided are quite low, in the order of 100 per year (and falling).
The Lancet article found that in the Americas there are about 37 excess deaths per 100,000 people per year, or about 1000 times per per capita than the 2011-2020 average in the NASA article.
I'm not denying that global warming may make some small-to-moderate part of the world uninhabitable (at least without access to electricity or running water). Indeed, half of Vietnam may be flooded.
Still, wet-bulb temperatures of 35 degrees is extremely hot and quite rare. I doubt we will see death tools in the millions per year in our lifetime, which is what it would need to be to match what cold weather or indoor air polution is already causing.
>the numbers listed in the article you provided are quite low, in the order of 100 per year (and falling).
Those were deaths in the US, not globally or in the Americas. The US has just about the highest percentage of households with ACs of any country in the world and so is, broadly speaking, less susceptible to deaths from severe heatwaves even should they occur. Globally, the figure is more like five million [1] between heat and cold.
The guardian article you link is based on the lancet article I provided.
What the headline doesn't show, is that from those 5 million, over 80% is cold related.
Also, if you travel a bit in third world countries, you may be surprised by how many have access to air conditioning, either in their own house or (in an emergency) some relative or neighbour nearby.
From what I've seen there is little consensus; they seem somewhere between nearly a non-issue and apocalyptic. But James Hansen, who has been eerily prescient about everything so far published a paper last year much more on the apocalyptic end.
