This is a linkpost for the article Global death rate from rising temperatures projected to surpass the current death rate of all infectious diseases combined, published by Climate Impacts Lab, based on this study.
Bill Gates summarised this as follows:
In other words, by 2060, climate change could be just as deadly as COVID-19, and by 2100 it could be five times as deadly.
From the summary article:
New study from the Climate Impact Lab finds people in poor parts of the world are disproportionately vulnerable to the risk of death associated with increased heat.
...the study projects that climate change’s effect on temperatures could raise global mortality rates by 73 deaths per 100,000 people in 2100 under a continued high emissions scenario, compared to a world with no warming. That level is roughly equal to the current death rate for all infectious diseases—including tuberculosis, HIV/AIDS, malaria, dengue, yellow fever, and diseases transmitted by ticks, mosquitos, and parasites—combined (approximately 74 deaths per 100,000 globally).
As far as I'm aware, this modelling also excludes potential exacerbating effects that climate change has on infectious diseases, e.g through the expansion of tropical regions leading to vastly more deaths from malaria.
This latest modelling could impact conclusions on the relative importance of climate change, e.g. examined here, though some estimates indicate that work to mitigate climate change could be more effective than many global health interventions, depending on our assumptions.
Thanks for the link, this is interesting!
A couple of quick thoughts from glancing at the paper (more hopefully later):
1) It is a first draft / working paper, not peer-reviewed (though the website frames it as if it was a finished study).
2) Some of the central assumptions seem quite selected for finding maximum impact, e.g. the 73 death per 100,000 people comes from a model run with RCP 8.5 which is currently seen as an extreme case, not business as usual but considerably worse, https://thebreakthrough.org/issues/energy/3c-world). The combination with SSP3 as the socio-economic scenario also seems to point in the direction of worst case assumption as this is a scenario of low/difficult adaptation, https://www.sciencedirect.com/science/article/pii/S0959378016300838 ). So, yes, 73 deaths per 100,000 from heat is possible but it is probably in the top 5% of the distribution of worst outcomes based on what we now think is realistic.
3) Something else that made me a bit worried about the bias in the direction of finding high impact was this statement "This projection accounts for adaptations to climate that populations are likely to make, given historical patterns of adaptation." One of the key features of expectable changes in the world to 2100, especially in high emissions scenarios, is that currently poor countries get a fair deal richer and use a lot more energy (in RCP 8.5 we could all burn lots of coal). So, it seems that the accounting for adaptation seems minimal compared to what one might expect, more adaptation beyond historical patterns as those countries get richer and have more resources available.
4) I am not saying it is a bad study and I am not really qualified to assess that on the deeper details, but I often find a lot of the climate-impact related literature to work with assumptions that seem very focused on finding maximal impacts (or with article titles exaggerating what the paper actually says, even in journals like Nature/Science etc.), a kind of publication bias that has made me quite skeptical of any single study.
The copy you have is their 2019 version of the paper. The figure 9 I am referring to is their most recent 2020 NBER Working Paper version of the paper linked in the original post.
I agree that the RCPs, which were made in 2011, are outdated at this point. This is in large part because of the strong performance of renewable energy over the last decade. The RCPs at this point are still the standard emissions scenarios that are used in scientific papers, although I expect them to be updated in the near future when the next IPCC report comes out. Somewhere betw... (read more)