I think I remain confused as to what you mean with āall deaths from non-optimal temperatureā.
I mean the difference between the deaths for the predicted and ideal temperature. From OWID:
The deaths from non-optimal temperature are supposed to cover all causes (temperature is a risk factor for death rather than a cause of death in GBD), not just extreme heat and cold (which only account for a tiny fraction of the deaths; see my last comment). I say āsupposedā because it is possible the mortality curves above are not being modelled correctly, and this applies even more to the mortality curves in the future.
So to me it seems you are saying āI donāt trust arguments about compounding risks and the data is evidence for thatā whereas the data is inherently not set up to include that concern and does not really speak to the arguments that people most concerned about climate risk would make.
My understanding is that (past/āpresent/āfuture) deaths from non-optimal temperature are supposed to include conflict deaths linked to non-optimal temperature. However, I am not confident these are being modelled correctly.
I was not clear, but in my last comment I mostly wanted to say that deaths from non-optimal temperature account for the impact of global warming not only on deaths from extreme heat and cold, but also on cardiovascular or kidney disease, respiratory infections, diabetes and all others (including conflicts). Most causes of death are less heavy-tailed than conflict deaths, so I assume we have a better understanding of how they change with temperature.
Ok, so I think we converge pretty much thenāessentially what I am saying is that people concerned about compounding risks would argue that these are not modeled correctly in GBD and that there is much more uncertainty there (and that the estimate is probably an underestimate, from the perspective of taking the compounding risk view seriously).
Makes sense. Just to clarify, the data on deaths and disease burden from non-optimal temperature until now are from GBD, but the projections for the future death rates from non-optimal temperature are from Human Climate Horizons.
Iām not sure it would change your underlying conclusions, but for what itās worth I took a quick look at the data/āmethods from Human Climate Horizons and think that it is likely an underestimate of future heat-related mortality.
This paper underlies the Human Climate Horizons/āOWID estimates. A few quick assumptions I think are worth highlighting:
1. The authors (by admission) do not consider the effects of humidity. Accurate humidity data is much harder to come by than temperature, and itās often not included in the down-scaled versions of the climate models, though some exceptions apply. However, itās potentially quite relevant for heat-related mortality, though there is some debate in the literature. Given that it is unlikely that incorporating humidity would decrease heat-related mortality, my own view here is that this pushes current estimates towards a lower bound.
2. The authors use climate model data that are downscaled with a technique called Bias-Correction Spatial Disaggregation (BCSD). This approach has two key assumptions in it: (1) it assumes that the relative spatial patterns in the training data will remain constant under future climate change, and (2) it is calibrated to monthly data, not day to day changes, which has the effect of dampening extreme values. In practice, these assumptions limit the ability to model things like extreme heat waves and heat domes, which can cause large fatality spikes (e.g. figure below from Washington State in 2021). Missing these features in some locations might be akin to missing almost all the possible heat related mortality in cooler climates.
Again, I donāt think these are significant enough to fundamentally change your conclusions, but I do think itās worth highlighting that these types of results can be quite sensitive to specifics of the climate modeling approaches that are used.
Thanks, Bradley, and welcome to the EA Forum! Strongly upvoted.
Given that it is unlikely that incorporating humidity would decrease heat-related mortality, my own view here is that this pushes current estimates towards a lower bound.
If adequately modelling humidity would increase heat deaths, I wonder whether it would also decrease cold deaths, such that the net effects is unclear.
In practice, these assumptions limit the ability to model things like extreme heat waves and heat domes, which can cause large fatality spikes (e.g. figure below from Washington State in 2021). Missing these features in some locations might be akin to missing almost all the possible heat related mortality in cooler climates.
As illustrated below, deaths from extreme cold and heat accounted for only a tiny fraction of the deaths from non-optimal temperature in 2015 in some countries, which attenuates the effect you are describing.
I mean the difference between the deaths for the predicted and ideal temperature. From OWID:
The deaths from non-optimal temperature are supposed to cover all causes (temperature is a risk factor for death rather than a cause of death in GBD), not just extreme heat and cold (which only account for a tiny fraction of the deaths; see my last comment). I say āsupposedā because it is possible the mortality curves above are not being modelled correctly, and this applies even more to the mortality curves in the future.
My understanding is that (past/āpresent/āfuture) deaths from non-optimal temperature are supposed to include conflict deaths linked to non-optimal temperature. However, I am not confident these are being modelled correctly.
I was not clear, but in my last comment I mostly wanted to say that deaths from non-optimal temperature account for the impact of global warming not only on deaths from extreme heat and cold, but also on cardiovascular or kidney disease, respiratory infections, diabetes and all others (including conflicts). Most causes of death are less heavy-tailed than conflict deaths, so I assume we have a better understanding of how they change with temperature.
Ok, so I think we converge pretty much thenāessentially what I am saying is that people concerned about compounding risks would argue that these are not modeled correctly in GBD and that there is much more uncertainty there (and that the estimate is probably an underestimate, from the perspective of taking the compounding risk view seriously).
Makes sense. Just to clarify, the data on deaths and disease burden from non-optimal temperature until now are from GBD, but the projections for the future death rates from non-optimal temperature are from Human Climate Horizons.
Thanks, Bradley, and welcome to the EA Forum! Strongly upvoted.
If adequately modelling humidity would increase heat deaths, I wonder whether it would also decrease cold deaths, such that the net effects is unclear.
As illustrated below, deaths from extreme cold and heat accounted for only a tiny fraction of the deaths from non-optimal temperature in 2015 in some countries, which attenuates the effect you are describing.