Anthropogenic activities are increasing the amount of carbon dioxide (CO2) in the atmosphere. There is mounting experimental evidence that lifetime exposur
The costs of a RCT to subject a population of humans over their lifespan to 600 ppm CO2 would be insane. Does this mean that we can’t say anything about how humans interact with elevated CO2 levels and have to guess from mice and first principles about blood bicarbonate levels? Well, there are a few groups of humans who regularly encounter elevated CO2 levels - highly urban populations, indoor office workers (especially in highly urban societies), and submariners.
Well we were at 300ppm - humans didn’t face a “potentially toxic” atmosphere.
We’re at 400ppm - atmosphere not feeling “potentially toxic” to me.
Indoor office workers get a workweek’s worth of indoor time at 1000 ppm CO2, then however long they spend commuting (I’m thinking trains here) more elevated CO2, then stay at home with 500+ ppm CO2 (levels can vary widely). Sure, office workers tend to be less healthy, but a “potentially toxic” atmosphere seems like stretching it.
Finally, there are submariners (and technically astronauts, but they tend to be fewer) who can spend months underway at a time and years cumulatively at 1000+ ppm CO2. How do they suffer? Not too differently from the rest of us -
https://pmc.ncbi.nlm.nih.gov/articles/PMC1128685/https://pubmed.ncbi.nlm.nih.gov/34412099/https://pubmed.ncbi.nlm.nih.gov/8515322/https://pmc.ncbi.nlm.nih.gov/articles/PMC5623552/
Okay, suppose that actually at 500ppm of CO2, it turns out that toddlers spontaneously combust. I think it’s probable that at some point in some urban city that there have been toddlers that have spent almost all of their time indoors and thus could have already been exposed to this condition without dying.
Is it possible that a 500, 600, 700, 800ppm CO2 cause conditions hazardous to human life or incompatible with human life? Yes, it’s possible and we won’t know for sure until we start pushing people into that condition for their whole life. Do I think it’s likely given that we know that people aren’t dropping like flies in highly urban societies like Hong Kong and Singapore and that submariners seem ok? No.
I myself am on team wet bulb event, but I think there is a subset of the population that believes (correctly) that they will be able to survive and thrive no matter how much they destroy the earth or whatever mass mortality events occur.
I agree that this will not be the first thing to kill us off, but i’d say we see things like early onset osteoporosis, malformation of limbs in newborns, increased maternal mortality and generally reduced life expectancy; maybe effects like delayed development in children with correspondingly reduced mental capacity.
Interestingly enough, i just last week saw a statistic that claimed that the first time ever, the youngest generation had an on average (marginally, but statistically relevant) lower intelligence than the one before. There are so many factors that can play into this, so i doubt that there is a measurable causation here, but it’s just one more puzzle piece in the large picture how we are shooting ourselves in our feet.
Like i said, the pH levels in the ocean (in combination with the massively rising heat levels there) are a much larger deal. It directly hits the basis of everything requiring oxygen globally, which will also hamper removal of CO2 (exacerbating the problem) and the food chain basis of every life form in the oceans (therefor hitting especially us humans on land depending on fishery), and as we already can see, the oceans are the thing that gets hit first by both the temperature rises and the CO2 levels.
The costs of a RCT to subject a population of humans over their lifespan to 600 ppm CO2 would be insane. Does this mean that we can’t say anything about how humans interact with elevated CO2 levels and have to guess from mice and first principles about blood bicarbonate levels? Well, there are a few groups of humans who regularly encounter elevated CO2 levels - highly urban populations, indoor office workers (especially in highly urban societies), and submariners.
Well we were at 300ppm - humans didn’t face a “potentially toxic” atmosphere. We’re at 400ppm - atmosphere not feeling “potentially toxic” to me. Indoor office workers get a workweek’s worth of indoor time at 1000 ppm CO2, then however long they spend commuting (I’m thinking trains here) more elevated CO2, then stay at home with 500+ ppm CO2 (levels can vary widely). Sure, office workers tend to be less healthy, but a “potentially toxic” atmosphere seems like stretching it. Finally, there are submariners (and technically astronauts, but they tend to be fewer) who can spend months underway at a time and years cumulatively at 1000+ ppm CO2. How do they suffer? Not too differently from the rest of us - https://pmc.ncbi.nlm.nih.gov/articles/PMC1128685/ https://pubmed.ncbi.nlm.nih.gov/34412099/ https://pubmed.ncbi.nlm.nih.gov/8515322/ https://pmc.ncbi.nlm.nih.gov/articles/PMC5623552/
Okay, suppose that actually at 500ppm of CO2, it turns out that toddlers spontaneously combust. I think it’s probable that at some point in some urban city that there have been toddlers that have spent almost all of their time indoors and thus could have already been exposed to this condition without dying.
Is it possible that a 500, 600, 700, 800ppm CO2 cause conditions hazardous to human life or incompatible with human life? Yes, it’s possible and we won’t know for sure until we start pushing people into that condition for their whole life. Do I think it’s likely given that we know that people aren’t dropping like flies in highly urban societies like Hong Kong and Singapore and that submariners seem ok? No.
I myself am on team wet bulb event, but I think there is a subset of the population that believes (correctly) that they will be able to survive and thrive no matter how much they destroy the earth or whatever mass mortality events occur.
I agree that this will not be the first thing to kill us off, but i’d say we see things like early onset osteoporosis, malformation of limbs in newborns, increased maternal mortality and generally reduced life expectancy; maybe effects like delayed development in children with correspondingly reduced mental capacity.
Interestingly enough, i just last week saw a statistic that claimed that the first time ever, the youngest generation had an on average (marginally, but statistically relevant) lower intelligence than the one before. There are so many factors that can play into this, so i doubt that there is a measurable causation here, but it’s just one more puzzle piece in the large picture how we are shooting ourselves in our feet.
Like i said, the pH levels in the ocean (in combination with the massively rising heat levels there) are a much larger deal. It directly hits the basis of everything requiring oxygen globally, which will also hamper removal of CO2 (exacerbating the problem) and the food chain basis of every life form in the oceans (therefor hitting especially us humans on land depending on fishery), and as we already can see, the oceans are the thing that gets hit first by both the temperature rises and the CO2 levels.