The total drylands population is 35% of the world population (~6% from desert/semi-desert). The total number of migrants, however, is 3.5% of world population. So less than 10% of those from drylands have left. But most such migrants move because of politics, war, employment rather than climate. The number leaving because of climate is less (and possibly much less) than 5% of the drylands population.
So suppose a billion people newly found themselves in drylands or desert, and that 5% migrated, making 50M migrants. Probably too few of these people will go to any country, let alone Greenland, to make it into a new superpower. But let’s run the numbers for Greenland anyway. Of the world’s 300M migrants, Greenland currently has only ~10k. So of an extra 50M, Greenland could be expected to take ~2k, so I’m coming in 5-6 orders of magnitude lower than the 1B figure.
It does still have some military relevance, and would be good to keep it neutral, or at least out of the hands of China/Russia.
It seems like we’ve identified a crux here: what will be the total number of people living in Greenland in 2100 / world with 4 degrees warming?
I have disagreements with some of your estimates.
The total drylands population is 35% of the world population
Large populations currently reside in places like India, China and Brazil. These currently non-drylands could be converted to drylands in the future (and also possibly desertified). Thus, the 35% figure could increase in the future.
So less than 10% of those from drylands have left.
Drylands are categorised into {desert, arid, semi-arid, dry sub-humid}. It’s only when a place is in the desert category, that people seriously consider moving out (for reference all of California comes under arid or semi-arid category). In the future, deserts could form a larger share of drylands, and less arid regions could form a smaller share. So, you could have more than 10% of people from places called “drylands” leaving in the future.
The total number of migrants, however, is 3.5% of world population.
Yes, that is correct. But that is also a figure from 2019. A more relevant question would be how many migrants would there be in 2100? I think it’s quite obvious that as the Earth warms, the number of climate migrants will increase.
So suppose a billion people newly found themselves in drylands or desert, and that 5% migrated, making 50M migrants.
I don’t really agree with the 5% estimate. Specifically for desertified lands, I would guess the %age of people migrating to be significantly higher.
Of the world’s 300M migrants, Greenland currently has only ~10k.
This is a figure from 2020 and I don’t think you can simply extrapolate this.
After revising my estimates to something more sensible, I’m coming with ~50M people in Greenland. So, Greenland would be far from being a superpower. I’m hesitant to share my calculations because my confidence level for my calculations is low—I wouldn’t be surprised if the actual number was upto 2 orders of magnitude smaller or greater.
A key uncertainity: Does desertification of large regions imply that in-country / local migration is useless?
The world, 4 degrees warmer. A map from Parag Khanna’s book Connectography
I’m not sure you’ve understood how I’m calculating my figures, so let me show how we can set a really conservative upper bound for the number of people who would move to Greenland.
Based on current numbers, 3.5% of world population are migrants, and 6% are in deserts. So that means less than 3.5/9.5=37% of desert populations have migrated. Even if half of those had migrated because of the weather, that would be less than 20% of all desert populations. Moreover, even if people migrated uniformly according to land area, only 1.4% of migrants would move to Greenland (that’s the fraction of land area occupied by Greenland). So an ultra-conservative upper bound for the number of people migrating to Greenland would be 1B*.37*.2*.014=1M.
So my initial status-quo estimate was 1e3, and my ultra-conservative estimate was 1e6. It seems pretty likely to me that the true figure will be 1e3-1e6, whereas 5e7 is certainly not a realistic estimate.
Hmm this is interesting. I think I broadly agree with you. I think a key consideration is that humans have a good-ish track record of living/surviving in deserts, and I would expect this to continue.
The total drylands population is 35% of the world population (~6% from desert/semi-desert). The total number of migrants, however, is 3.5% of world population. So less than 10% of those from drylands have left. But most such migrants move because of politics, war, employment rather than climate. The number leaving because of climate is less (and possibly much less) than 5% of the drylands population.
So suppose a billion people newly found themselves in drylands or desert, and that 5% migrated, making 50M migrants. Probably too few of these people will go to any country, let alone Greenland, to make it into a new superpower. But let’s run the numbers for Greenland anyway. Of the world’s 300M migrants, Greenland currently has only ~10k. So of an extra 50M, Greenland could be expected to take ~2k, so I’m coming in 5-6 orders of magnitude lower than the 1B figure.
It does still have some military relevance, and would be good to keep it neutral, or at least out of the hands of China/Russia.
Thanks Ryan for your comment!
It seems like we’ve identified a crux here: what will be the total number of people living in Greenland in 2100 / world with 4 degrees warming?
I have disagreements with some of your estimates.
Large populations currently reside in places like India, China and Brazil. These currently non-drylands could be converted to drylands in the future (and also possibly desertified). Thus, the 35% figure could increase in the future.
Drylands are categorised into {desert, arid, semi-arid, dry sub-humid}. It’s only when a place is in the desert category, that people seriously consider moving out (for reference all of California comes under arid or semi-arid category). In the future, deserts could form a larger share of drylands, and less arid regions could form a smaller share. So, you could have more than 10% of people from places called “drylands” leaving in the future.
Yes, that is correct. But that is also a figure from 2019. A more relevant question would be how many migrants would there be in 2100? I think it’s quite obvious that as the Earth warms, the number of climate migrants will increase.
I don’t really agree with the 5% estimate. Specifically for desertified lands, I would guess the %age of people migrating to be significantly higher.
This is a figure from 2020 and I don’t think you can simply extrapolate this.
After revising my estimates to something more sensible, I’m coming with ~50M people in Greenland. So, Greenland would be far from being a superpower. I’m hesitant to share my calculations because my confidence level for my calculations is low—I wouldn’t be surprised if the actual number was upto 2 orders of magnitude smaller or greater.
A key uncertainity: Does desertification of large regions imply that in-country / local migration is useless?
I’m not sure you’ve understood how I’m calculating my figures, so let me show how we can set a really conservative upper bound for the number of people who would move to Greenland.
Based on current numbers, 3.5% of world population are migrants, and 6% are in deserts. So that means less than 3.5/9.5=37% of desert populations have migrated. Even if half of those had migrated because of the weather, that would be less than 20% of all desert populations. Moreover, even if people migrated uniformly according to land area, only 1.4% of migrants would move to Greenland (that’s the fraction of land area occupied by Greenland). So an ultra-conservative upper bound for the number of people migrating to Greenland would be 1B*.37*.2*.014=1M.
So my initial status-quo estimate was 1e3, and my ultra-conservative estimate was 1e6. It seems pretty likely to me that the true figure will be 1e3-1e6, whereas 5e7 is certainly not a realistic estimate.
Hmm this is interesting. I think I broadly agree with you. I think a key consideration is that humans have a good-ish track record of living/surviving in deserts, and I would expect this to continue.