Billions of people will not die from climate change, if anything they would simply not be born.
That is already happening in almost every western democracy as fertility rates have dropped precipitously. That is not because we have any food shortages: it’s because people are choosing not to have kids because life is so expensive.
Europe now has hundreds of excess deaths from heat and hundreds of excess deaths from flooding due to events exacerbated or caused entirely by climate change most years. Africa likely already experiences tens of thousands of climate change related deaths each year, although attribution is tricky. Assuming that climate change and its effects are an exponentially escalating phenomenon, why would it be unthinkable that over the next 10/20/50/100 years the cumulative death toll of climate change will reach into the billions?
It's quite a leap of faith to extrapolate from hundreds up to billions, no?
It all depends ob your assumptions, i.e. the actual effects of climate change on extreme weather events, the capacity of various polities to adapt to these effects and how you would define "climate change related deaths" and the timeframe you are looking at.
Direct fatalities from weather related natural disasters (droughts, floods, storms, etc) between 2005 and 2024 worldwide are estimated somewhere around 200.000 people, so about 10.000 deaths per year [0].
If you assume (just for the sake of the argument) that climate change will increase this death toll by 10% every year for 100 years, direct deaths from natural disasters caused by climate change alone will amount to close to 140.000.000 deaths over that time period.
Add to this indirect deaths, i.e. premature deaths due to insufficient nutrition during childhood caused by drought, disease spread by floods, etc. etc.
And because the effects of climate change are mostly political in nature, you'll have to make some assumptions about that, too. Sea level rise will affect (as in inundate their current homes at least once a year) more than 600 million people by the year 2100 [1]. Many of these peoples will be displaced and depending on the political and economic capacity of their societies to cope with this displacement, this alone could result in millions of deaths.
Climate change is also a contributor to general political instability and the risk of both civil and nation state war. How do you account for those deaths?
In summary, the death toll of climate change can inherently not be known. But if you look at the next hundred years, I doubt you can assume a number of less than in the hundreds of millions, if we assume climate change effects based on current estimates of "status quo" emissions. Which makes emission reductions essential, because there is a literal connection between an additional ton of CO2 in the atmosphere and an increase in the number of deaths.
[0] https://ourworldindata.org/grapher/number-of-deaths-from-nat... [1] https://www.nature.com/articles/s41467-019-12808-z
Simply assuming 10% compound growth year-on-year without any basis is, frankly, ridiculous.
https://ourworldindata.org/part-one-how-many-people-die-from...
"Cold deaths vastly outnumber heat-related ones, but mostly due to “moderate” rather than extremely cold conditions."
Maybe read the second part of this analysis? https://ourworldindata.org/part-two-how-many-people-die-from...
Cold deaths will decrease in high-latitude countries (which tend to be sparsely inhabited) but heat deaths will increase in low latitude countries (i.e. places like India). The exact effects of this will depend on political factors (adaption), but it is unlikely that the decrease in cold deaths will compensate the increase in heat deaths. Also, the people dying from heat will still be dead.
That's a useful baseline for future comparisons.
Currently (mostly) cities don't see Death Valley or Marble Bar range tempretures or beyond .. this will change.
~ https://www.climatechangenews.com/2025/07/14/to-help-people-...Extreme heat could lead to 30,000 deaths a year in England and Wales by 2070s, say scientists
~ https://www.theguardian.com/environment/2025/jul/10/extreme-...
That would be roughly on par with Germany's deaths related to infections contracted in a hospital. That doesn't make it into headlines.
That's just the UK (high latitude), at tempretures lower than current tempretures in Death Valley / Marble Bar.
Give it time for higher tempretures to reach dense urban centres, look to India and equatorial countries that'll experience both high temp and high humidity and you'll see heat exhaustion deaths rise to well past those anglocentric numbers.
The more serious numbers will come from climate related conflict and migration in any case (assuming no change in increasing emmissions, even assuming a flattening to a steady human annual addition).
>people are choosing not to have kids because life is so expensive.
Finally a positive outcome of capitalism!
Having children is subsidized where I come from. To a point where getting pregnant is a strategy to secure a form of UBI for certain low-income people. I think the reasons for lowered birth rates are much more hedonistic and less related to costs.
Not wanting to bring children into an overpopulated polluted overheating stormy flooding jobless fascist warring world of burning bombed out cities and ICE concentration camps run by heath care and science denying oligarchs and religious zealots is hardly hedonism.