I would be curious to know your thoughts on the extent to which there is consensus that global warming will result in more deaths related to temperature and “natural” disasters accounting for adaptation. These may well increase in the future, but so far it looks like they have been decreasing.
Zhao 2021 found that, in the last 15 years, the decrease in cold-related deaths was 2.43 (= 0.51/0.21) times the increase in heat-related deaths:
From 2000–03 to 2016–19, the global cold-related excess death ratio changed by −0·51 percentage points (95% eCI −0·61 to −0·42) and the global heat-related excess death ratio increased by 0·21 percentage points (0·13–0·31), leading to a net reduction in the overall ratio.
From OWID, deaths per capita from “natural” disasters have been decreasing:
Thanks a lot for the response! I was the main researcher for these articles—here are a few thoughts from me and the team:
It’s a little tricky for us to evaluate the consensus on these issues ourselves as we don’t have the capacity or expertise to review all the relevant papers and assess their relative influence. (We’d welcome anyone sharing their views on this, especially if they have expertise in the field!)
Because of this, we typically defer to respected authorities – especially the IPCC – which is likely a decent proxy for expert consensus. While any one institution will inevitably have its shortcomings, the IPCC’s comprehensiveness in reviewing the literature is impressive, and they do a fairly good job of representing their uncertainty based on the literature in their reports.
That being said, there seems to be a lot of uncertainty about expected adaptation efforts, perhaps more so than there is uncertainty about the direct effects of climate change, and the extent to which the IPCC provides estimates accounting for adaptation depends on the problem. In short – we don’t really know, (though we’re open to being corrected on this).
Because of this, when trying to estimate the value of working on adaptation, given high uncertainty about how much of it will take place without our intervention, as well as a reportedly widening adaptation finance gap, it’s still worth thinking about the expected impacts assuming minimal or current-trajectory adaptation. Though, naturally, the more we learn about the impact of expected adaptation efforts, the better.
Here’s a few more specific points on deaths from non-optimal temperatures and natural disasters:
On temperature and mortality:
When discussing the promisingness of an adaptation response to heat stress, we think what matters is the absolute numbers of heat-stress-related deaths, which we can be quite confident will significantly increase, and not whether on net climate will cause or prevent more deaths (taking into account other types of deaths prevented). We included the estimate that increases in fatalities will outweigh reduction in deaths because it provides interesting and relevant context, not because it directly bears on how promising this area of adaptation is.
It’s also worth noting that even Zhao (2021) claims that ‘in the long run, climate change is expected to increase the [temperature-related] mortality burden’, even if it reduces mortality in the short term. They don’t give any concrete projections, so it’s unclear the extent to which the numbers we’ve given align with this claim – but the direction is the same. Nonetheless, this does complicate the discussion around temperature-related mortality, so thanks for bringing it to our attention!
On natural disasters:
First, although fatalities from natural disasters have decreased, most of this reduction has been in high-income countries (if you look at the OWID page and filter by low-income countries, the downward trend is much less clear).
Additionally, looking at the decadal average of all natural disasters can hide how sparse the data points driving this impression are. If we look at the year-by-year view of natural disaster deaths, just a handful of terrible events are responsible for the vast majority of deaths throughout the 20th century, which means we’re wary about inferring long-term trends from the decadal view – especially for events that fit a power-law distribution.
On top of this, looking at the specific kinds of natural disasters we’re discussing, it’s not clear they’re subject to the same downward trend, even on the decadal view. For instance, the OWID chart on natural disasters shows deaths from extreme temperatures have sharply increased in recent decades, and annual flood deaths have been fairly flat since the 1970s.
And just as a general point on the importance of climate-related extreme weather events, only counting fatalities may also give us a misleading picture, since it excludes other significant effects like damage to infrastructure, worsened mental health, and cumulatively huge economic losses. Again referring to the OWID page, the economic damage inflicted by natural disasters is much higher now than it was in the 1960s(as a share of GDP), despite them causing fewer deaths.
Our current view is that looking at the century-long average as an estimate of expected future fatalities may be an overestimate (primarily due to reductions in high-income countries), but it’s unclear that existing adaptation efforts will similarly continue to reduce harms going forward (or prevent potential rises in disasters where such are expected due to climate change).
The bottom line is we think there’s a lot of complexities in the analysis of the quantitative estimates, especially when adaptation and human response is a critical factor. But we believe that the areas we’ve identified are nonetheless promising areas to have a positive impact given what we know.
You cannot infer trends in the climate-related economic impact of natural disasters from trends in the total damage of natural disasters or trends in the per capita economic impact of natural disasters. The economic costs of natural disasters is influenced by the increasing economic value of areas that are vulnerable to climate change. Eg here is a Miami beach a century ago compared to today
You need to adjust for this by producing an estimate of normalised damages (discussedhereby one of the most cited climate researchers). For example, here is the normalised cost to the US of hurricanes since 1900. i.e. suggestive of increased losses on the order of $5-10bn over the course of a century, which is about 0.2% of US GDP.
Despite what you read in the media,according to the IPCC, for the vast majority of extreme events, it is not yet possible to attribute with confidence any change to climate change. A white entry in the table means that a signal cannot yet be noticed with confidence. A blue entry means the signal is increasing. An orange entry means the signal is decreasing.
There is as yet no clear evidence of a climate signal for precipitation, flooding, drought, fire weather, wind speed, storms, cyclones, and coastal flooding.
I don’t agree with your points on natural disasters. I am going to post below the charts from OWID on weather-related deaths, including absolute numbers and per capita numbers. Some comments:
These numbers are (now thankfully) small, falling well well short of catastrophe.
There have been massive declines in the absolute and per person risk from the most threatenting risks (droughts, floods). This is due to economic development.
To characterise the trend in flood deaths as anything other than a dramatic downward trend seems clearly wrong.
For all the media discussion of wildfires and a world on fire, we have passed 1 degree and wildfire deaths are 140 per year, which is far exceeded by the number of people who die falling off ladders. Perhaps not today, but at some point the media and the scientific community are going to face scrutiny for exaggerating on climate change.
Extreme temperature deaths are increasing, but this would (I assume) include cold-related deaths and heat-related deaths. According to Zhao et al, cold-related deaths are 9x heat-related deaths today, so one would expect the 1C we have already experienced to have reduced the death toll. In the absence of climate change, the increase would be more pronounced. (I haven’t looked into the data source though)
There is large net migration (i.e. in the millions of people) to low lying coastal areas in Asia that are most vulnerable to coastal storms. This, rather than climate change significantly confounds trends in per capita or total storm deaths. Nevertheless, storm deaths are at historic lows for any ten or twenty year period in the 20th Century.
As indicated by your comment, if your concern is reducing deaths from climate change, the main thing to do seems to be to increase economic growth in poor countries given that is what drove the massive decline in weather-related deaths over the last 200 years.
I again genuinely appreciate this feedback, and what I said above also applies here: we’ll revisit the content with your comments in mind and will likely make some changes. Because I’ve already given some object-level discussion in this thread, I wanted to provide a response to this claim:
For all the media discussion of wildfires and a world on fire, we have passed 1 degree and wildfire deaths are 140 per year, which is far exceeded by the number of people who die falling off ladders. Perhaps not today, but at some point the media and the scientific community are going to face scrutiny for exaggerating on climate change.
Whilst you’re correct that direct deaths from wildfires are low, these are not what primarily drive deaths caused by wildfires; the indirect effects from wildfires (via air pollution) are much larger.
For instance, Ye, et al (2022) attributes over 130,000 deaths to wildfire-related PM2.5 exposure in Brazil from 2000-2016 (>8,000 per year), and Chen et al (2021) seemingly attributes around 30,000 deaths per year from 2000-2016 to wildfire-caused pollution, globally.
It is difficult for me to verify every assumption in these papers, but even if they’re significant overestimates, it’s clear that indirect deaths from wildfires vastly outnumber direct deaths. Several other papers that directionally support this point (with a fairly wide range between estimates):
Of course, the extent to which climate change drives wildfires, both now and into the future as warming increases, is an important crux in how many of these deaths we should attribute to climate change. But, when evaluating the importance of wildfires themselves (e.g. when thinking about adaptation), looking just at the direct harms will lead us to significantly underestimate their impact.
Thanks for sharing!
I would be curious to know your thoughts on the extent to which there is consensus that global warming will result in more deaths related to temperature and “natural” disasters accounting for adaptation. These may well increase in the future, but so far it looks like they have been decreasing.
Zhao 2021 found that, in the last 15 years, the decrease in cold-related deaths was 2.43 (= 0.51/0.21) times the increase in heat-related deaths:
From OWID, deaths per capita from “natural” disasters have been decreasing:
Thanks a lot for the response! I was the main researcher for these articles—here are a few thoughts from me and the team:
It’s a little tricky for us to evaluate the consensus on these issues ourselves as we don’t have the capacity or expertise to review all the relevant papers and assess their relative influence. (We’d welcome anyone sharing their views on this, especially if they have expertise in the field!)
Because of this, we typically defer to respected authorities – especially the IPCC – which is likely a decent proxy for expert consensus. While any one institution will inevitably have its shortcomings, the IPCC’s comprehensiveness in reviewing the literature is impressive, and they do a fairly good job of representing their uncertainty based on the literature in their reports.
That being said, there seems to be a lot of uncertainty about expected adaptation efforts, perhaps more so than there is uncertainty about the direct effects of climate change, and the extent to which the IPCC provides estimates accounting for adaptation depends on the problem. In short – we don’t really know, (though we’re open to being corrected on this).
Because of this, when trying to estimate the value of working on adaptation, given high uncertainty about how much of it will take place without our intervention, as well as a reportedly widening adaptation finance gap, it’s still worth thinking about the expected impacts assuming minimal or current-trajectory adaptation. Though, naturally, the more we learn about the impact of expected adaptation efforts, the better.
Here’s a few more specific points on deaths from non-optimal temperatures and natural disasters:
On temperature and mortality:
When discussing the promisingness of an adaptation response to heat stress, we think what matters is the absolute numbers of heat-stress-related deaths, which we can be quite confident will significantly increase, and not whether on net climate will cause or prevent more deaths (taking into account other types of deaths prevented). We included the estimate that increases in fatalities will outweigh reduction in deaths because it provides interesting and relevant context, not because it directly bears on how promising this area of adaptation is.
It’s also worth noting that even Zhao (2021) claims that ‘in the long run, climate change is expected to increase the [temperature-related] mortality burden’, even if it reduces mortality in the short term. They don’t give any concrete projections, so it’s unclear the extent to which the numbers we’ve given align with this claim – but the direction is the same. Nonetheless, this does complicate the discussion around temperature-related mortality, so thanks for bringing it to our attention!
On natural disasters:
First, although fatalities from natural disasters have decreased, most of this reduction has been in high-income countries (if you look at the OWID page and filter by low-income countries, the downward trend is much less clear).
Additionally, looking at the decadal average of all natural disasters can hide how sparse the data points driving this impression are. If we look at the year-by-year view of natural disaster deaths, just a handful of terrible events are responsible for the vast majority of deaths throughout the 20th century, which means we’re wary about inferring long-term trends from the decadal view – especially for events that fit a power-law distribution.
On top of this, looking at the specific kinds of natural disasters we’re discussing, it’s not clear they’re subject to the same downward trend, even on the decadal view. For instance, the OWID chart on natural disasters shows deaths from extreme temperatures have sharply increased in recent decades, and annual flood deaths have been fairly flat since the 1970s.
And just as a general point on the importance of climate-related extreme weather events, only counting fatalities may also give us a misleading picture, since it excludes other significant effects like damage to infrastructure, worsened mental health, and cumulatively huge economic losses. Again referring to the OWID page, the economic damage inflicted by natural disasters is much higher now than it was in the 1960s (as a share of GDP), despite them causing fewer deaths.
Our current view is that looking at the century-long average as an estimate of expected future fatalities may be an overestimate (primarily due to reductions in high-income countries), but it’s unclear that existing adaptation efforts will similarly continue to reduce harms going forward (or prevent potential rises in disasters where such are expected due to climate change).
The bottom line is we think there’s a lot of complexities in the analysis of the quantitative estimates, especially when adaptation and human response is a critical factor. But we believe that the areas we’ve identified are nonetheless promising areas to have a positive impact given what we know.
You cannot infer trends in the climate-related economic impact of natural disasters from trends in the total damage of natural disasters or trends in the per capita economic impact of natural disasters. The economic costs of natural disasters is influenced by the increasing economic value of areas that are vulnerable to climate change. Eg here is a Miami beach a century ago compared to today
You need to adjust for this by producing an estimate of normalised damages (discussed here by one of the most cited climate researchers). For example, here is the normalised cost to the US of hurricanes since 1900. i.e. suggestive of increased losses on the order of $5-10bn over the course of a century, which is about 0.2% of US GDP.
Despite what you read in the media, according to the IPCC, for the vast majority of extreme events, it is not yet possible to attribute with confidence any change to climate change. A white entry in the table means that a signal cannot yet be noticed with confidence. A blue entry means the signal is increasing. An orange entry means the signal is decreasing.
There is as yet no clear evidence of a climate signal for precipitation, flooding, drought, fire weather, wind speed, storms, cyclones, and coastal flooding.
I don’t agree with your points on natural disasters. I am going to post below the charts from OWID on weather-related deaths, including absolute numbers and per capita numbers. Some comments:
These numbers are (now thankfully) small, falling well well short of catastrophe.
There have been massive declines in the absolute and per person risk from the most threatenting risks (droughts, floods). This is due to economic development.
To characterise the trend in flood deaths as anything other than a dramatic downward trend seems clearly wrong.
For all the media discussion of wildfires and a world on fire, we have passed 1 degree and wildfire deaths are 140 per year, which is far exceeded by the number of people who die falling off ladders. Perhaps not today, but at some point the media and the scientific community are going to face scrutiny for exaggerating on climate change.
Extreme temperature deaths are increasing, but this would (I assume) include cold-related deaths and heat-related deaths. According to Zhao et al, cold-related deaths are 9x heat-related deaths today, so one would expect the 1C we have already experienced to have reduced the death toll. In the absence of climate change, the increase would be more pronounced. (I haven’t looked into the data source though)
There is large net migration (i.e. in the millions of people) to low lying coastal areas in Asia that are most vulnerable to coastal storms. This, rather than climate change significantly confounds trends in per capita or total storm deaths. Nevertheless, storm deaths are at historic lows for any ten or twenty year period in the 20th Century.
As indicated by your comment, if your concern is reducing deaths from climate change, the main thing to do seems to be to increase economic growth in poor countries given that is what drove the massive decline in weather-related deaths over the last 200 years.
I again genuinely appreciate this feedback, and what I said above also applies here: we’ll revisit the content with your comments in mind and will likely make some changes. Because I’ve already given some object-level discussion in this thread, I wanted to provide a response to this claim:
Whilst you’re correct that direct deaths from wildfires are low, these are not what primarily drive deaths caused by wildfires; the indirect effects from wildfires (via air pollution) are much larger.
For instance, Ye, et al (2022) attributes over 130,000 deaths to wildfire-related PM2.5 exposure in Brazil from 2000-2016 (>8,000 per year), and Chen et al (2021) seemingly attributes around 30,000 deaths per year from 2000-2016 to wildfire-caused pollution, globally.
It is difficult for me to verify every assumption in these papers, but even if they’re significant overestimates, it’s clear that indirect deaths from wildfires vastly outnumber direct deaths. Several other papers that directionally support this point (with a fairly wide range between estimates):
Kollanus et al (2016): >1,000 deaths in Europe in both 2005 and 2008
Neumann et al (2021): 720 deaths per year in Western US, 1996-2005
Pan et al (2023): 4,000 deaths per year in US, 2012-2014
Johnston et.al (2015): 339,000 global deaths per year, 1997-2006 (from landscape fires—a broader category than wildfires)
Roberts & Wooster (2021): 677,745 global deaths per year, 2016-2019 (also from landscape fires)
Of course, the extent to which climate change drives wildfires, both now and into the future as warming increases, is an important crux in how many of these deaths we should attribute to climate change. But, when evaluating the importance of wildfires themselves (e.g. when thinking about adaptation), looking just at the direct harms will lead us to significantly underestimate their impact.
Yes, those are good points
Thanks for the detailed reply, Dylan!