Does environmental stress drive migration?

New comprehensive analysis ranks environmental and social factors for explaining migration globally as well as in each country—and it’s more complicated than previous understanding suggests

Peer-Reviewed Publication


Feature importance ranking for net-negative migration

With the United Nations climate conference in Glasgow, the world is focused on the consequences of a climate crisis and how we can still change course. Yet while climate-driven migration has been deemed a major threat in public discourse and academic research, comprehensive studies that take into account both environmental and social factors globally have been scarce. Now, with the help of machine learning, a research team led by Aalto University has drawn a clearer picture of the factors involved in migration for 178 countries.

Traditionally, research on climate change-related migration has taken a linear approach, concentrating on whether or not environmental stress is directly related to migration—typically for one country or set of countries at a time. Researchers have known that social factors must also play a role, but studying both at a global scale, with all necessary information for all countries and sub-regions, has been a major challenge.

‘Perhaps the most surprising finding from our study is that, when we look at the overall picture, social factors are more important than environmental factors in explaining migration. And regardless of the level of income involved, gross national income was the key factor in explaining net-migration in half of countries,’ says Venla Niva, a doctoral student at Aalto University and lead author of the study published in Environmental Research Letters.

In their analysis, the team made use of a machine learning technique, called random forest analysis, well suited to dealing with the complex relationships seen between variables in very large sets of data. This allowed the researchers to explain the importance of each factor for each of the countries studied. Social factors were assessed in terms of income, education in years, life expectancy, government effectiveness; environmental factors were measured through natural hazards, water risk, food production scarcity, and drought prevalence.

For example, income was the most important factor in Finland and Ethiopia, while in the US and South Africa education explained the majority of within-country variation for net-negative migration. In areas like the US and Ethiopia where in-migration surpassed out-migration, health was the most important factor, whereas in Finland and South Africa income was the feature that best explained net-positive migration. Globally, out of environmental variables, drought risk was the most important variable. In Ethiopia, two environmental variables ranked in the top three factors in terms of net-positive migration: drought risk and water risk.

The data used in the study is from 1990 to 2000, the most recent period for which information from 178 countries of the world, both high- and low-income, is available at the level of detail studied: 10 km by 10 km units.

‘Very detailed data at the local, rather than national, level lets us see the areas from which people have moved, as well as the areas people have moved to—whether that’s across borders or within the country. For example, if a specific area has seen environmental stress, like a drought, we can zoom in to see whether there has been a loss of people due to out-migration over that same period,’ says Niva.

Majority of net-migration occurred in vulnerable regions

That same level of detail confirmed that while environmental pressures alone are unlikely to directly cause migration, environmental pressures in departure countries or areas are relevant.  More than half (58%) of net-negative migration occurred in areas with high environmental stress and low capacity to adapt to changes.

‘This is one of the biggest challenges of our times: the areas under environmental stress are the areas with lowest resilience, which means that they aren’t well equipped to cope with changes. As populations in Africa and South Asia are rapidly growing, decision-makers need to help build capacity to ensure vulnerable areas can deal with the consequences of a warming climate as well as other environmental stressors,’ explains Matti Kummu, professor of global water and food issues at Aalto University.

To get a better sense of how the factors explain more recent global migration, the team is currently creating a dataset that spans 2000-2020, with results expected in the next year or so.

‘For now what we can say is that with this recently published study we’ve been able to identify the basic factors involved in migration—next we’ll explore if and how the factors have changed in importance over time, as the climate heats up,’ says Kummu.     



Environmental Research Letters




Global migration is driven by the complex interplay between environmental and social factors



From EurekAlert!

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Tom Halla
November 5, 2021 6:06 pm

I saw no mention of escaping bad governments or their policies, which are rather more acute a problem than climate change.

Steve Case
Reply to  Tom Halla
November 5, 2021 6:09 pm

Ha ha ha ha ha ha ha! You beat me to it by two minutes (-:

John I Reistroffer
Reply to  Tom Halla
November 5, 2021 6:17 pm

Six million people out of a 27 million population have left Venezuela; so Tom you are exactly right! Runaway inflation, corruption, totalitarian gvt., oppression…etc, etc.

Nothing to do with climate.

Reply to  John I Reistroffer
November 6, 2021 5:03 am

Most of them flee to Florida, or Colombia where the climate is similarly warm. Not many Venezuelans settle in Canada or Norway!

John the Econ
Reply to  Tom Halla
November 5, 2021 6:31 pm

…or a shot at a $450,000 check on top of other benefits.

Reply to  John the Econ
November 5, 2021 10:06 pm

The President of Indonesia explained why people smugglers succeeded in attracting fare paying boat passengers to sail to Australia to seek asylum but on “Suspected Illegal Entry Boats” as illegal immigrants, and travelling via Indonesia from countries such as Afghanistan , Sri Lanka and others.

The President of Indonesia advised the Australian Government to remove incentives he called “sugar on the table”.

Reply to  Dennis
November 6, 2021 4:47 pm

For Indonesians involved in the people smuggling trade to Australia,
It was a lucrative game of ‘pass the parcel”
With the aim being to pass the ‘refugees’ on to some other country ( Australia ) while extracting cash in US dollars as they were passed on._

Tom Abbott
Reply to  John the Econ
November 6, 2021 5:47 am

That $450,000 is only for kids separated during the Trump administration. It doesn’t apply to kids separated under the Obama-Biden administration, or the current Biden administration. So future illegal aliens are out of luck as far as that goes.

John the Econ
Reply to  Tom Abbott
November 6, 2021 10:43 am

But it contributes to the impression that there could be benefits, which is why many come in the first place.

Reply to  Tom Abbott
November 6, 2021 12:59 pm

only for kids separated during the Trump administration

Ahahaha go ahead and believe that

Tom Abbott
Reply to  Ruleo
November 6, 2021 6:03 pm

Why wouldn’t I believe that?

Obama and Biden did the same thing Trump did. Now, Biden is trying to punish Trump for doing the same thing he did. And then Biden actually gets up there in public and feigns indignation at Trump’s actions, when they were just like Biden’s actions. Biden should be indignant at himself.

But it’s all an act. Biden only cares about politics and tearing down anyone who opposes him. A typical low-life Democrat. His indignation is a tactic.

Ben Vorlich
Reply to  Tom Halla
November 6, 2021 2:07 am

Yes my thoughts exactly.
Two main reasons for migration in the post LIA World politics/religion or to find a better life as economic migrants. My family tree goes back to Argyllshire and North Uist my grandparents met in Glasgow though. I have very few blood relatives in Scotland but many in Canada, USA, Australia, New Zealand and Chile that I’ve found when researching the family tree. All left the UK either as a result of being replaced by sheep (political) or unemployment (economic).

Tom Halla
Reply to  Ben Vorlich
November 6, 2021 4:59 am

Rather the same for some of my own ancestors. Either leaving central or Northern Europe due to economics or politics. Austria, Germany, or Sweden had both economic and political problems in the 19th Century, and my grandfather’s family skipped Mexico to avoid a revolution.

Reply to  Tom Halla
November 6, 2021 5:01 am

You mean there are good governments?

I rather believe that all governments are bad, with only variations in badness to distinguish one from another.

Reply to  Duane
November 6, 2021 5:05 am

I believe it was Ben Franklin who quipped, “Democracy is the worst form of government … except for all the others.”

Tom Halla
Reply to  Duane
November 6, 2021 7:50 am

I thought that was Winston Churchill

Reply to  Tom Halla
November 6, 2021 8:15 am

You might be right. The sentiment is correct.

Reply to  Tom Halla
November 7, 2021 3:12 pm

If Ben Franklin made the aphorism Churchill did well to take it up. He was a master at that. If he was the originator Franklin said something else as eminently quoatabe.

Tom Halla
Reply to  Philo
November 7, 2021 3:31 pm

It would have been an anachronism for it to have been Franklin. The US was the only democracy then in existence. There were defunct historical examples, like the Greeks or Romans, or the Netherlands in the then fairly recent past, but democracies were then showing one example.

Curious George
Reply to  Tom Halla
November 6, 2021 7:42 am

The Aalto University has been thoroughly finladized. They don’t dare to mention socialism at all.

Steve Case
November 5, 2021 6:08 pm

‘Perhaps the most surprising finding from our study is that, when we look at the overall picture, social factors are more important than environmental factors in explaining migration.
Social factors? What they couldn’t bring themselves to say, Politics?

Reply to  Steve Case
November 6, 2021 8:21 am

“Social factors” is rather different than politics. Politics is about government, while social factors are about how people and groups of people interact with each other.

Examples of social factors include religious persecution; sectarian violence; discrimination based upon race, culture, national origin, etc.

But yeah, government oppression is a key driver of outmigration.

Tom Gelsthorpe
November 5, 2021 6:19 pm

Are shoveling snow, scraping frozen sleet off car windows, and slipping & falling on the ice “environmental factors”?

If so, total population growth of our three warmest states — Florida, Texas and California — from 5 million in 1900 to 90 million today, shows how the environment influences migration. Almost all that growth comes from people moving from cooler areas to those three states over the last 120 years. Even Cubans in Florida and Mexicans & Guatemalans in CA, migrated from cooler home places to warmer new places.

Gunga Din
Reply to  Tom Gelsthorpe
November 6, 2021 6:08 am

Don’t forget that California lost a seat in the House due to people leaving for political reasons.
(New York also)

November 5, 2021 6:37 pm

‘Perhaps the most surprising finding from our study is that, when we look at the overall picture, social factors are more important than environmental factors in explaining migration.”

How surprising! These researches are running out of ideas. I have one! Try researching how climate change plays a part in pet ownership or maybe language evolution or what about grass mowing?

H. D. Hoese
November 5, 2021 6:57 pm

From the text–
“Random forest regression was utilized to quantitate the independent importance of each variable (table 1) in explaining both net-negative and net-positive migration. Random forest regression is a machine learning algorithm that uses an ensemble of multiple bootstrap sample predictions (decision trees) to produce a consensus regression fit (Breiman 2001). ” From Table 1 “Based on Smits and Permanyer (2019), missing values interpolated and extrapolated using method from Kummu et al (2018).”

Interpolate- 1 to alter or corrupt (as a text) by inserting new or foreign matter. Someone familiar with neo-statistics needs to explain. Random forest analysis doesn’t seem to.–“For random forest analysis, the net-migration data were then normalized with the respective population count in the initial timestep (1990) in each grid cell in order to address the effect of population to net-migration count. Here it is important to note that net-migration accounts for all types of mobility and does not distinguish between voluntary and forced migration, for instance.”

R Grubb
November 5, 2021 7:16 pm

Follow the money. That’s what emigrants do. The poor would emigrate to the Sahara or Siberia if the money was there for them.

November 5, 2021 8:00 pm

Is “machine learning” (mentioned several times) just another term for AI which is just another form of computer modeling? You can argue the differences between them but you can’t argue the GIGO factor.

Reply to  markl
November 5, 2021 9:30 pm

From ”Why machine learning is becoming a joke”

There was a time in the recent past when data scientists used to build ML algorithms from scratch. Before these new, fancy, and “sophisticated” libraries took over, true data scientists were aware of the underlying mechanics of the algorithms. They really knew about the models they run and the mathematics they used.
Today, everyone is a data scientist and it disintegrates the significance of this profession. With the help of highly abstract libraries like Keras and Scikit-Learn, a newbie can write the code without actually knowing what’s happening beneath.

Zig Zag Wanderer
Reply to  Mike
November 5, 2021 10:25 pm

a newbie can write the code without actually knowing what’s happening beneath.

This is indeed the difference between a software developer and a hack. The trouble is that so many people are now able to write code without understanding anything about how it works. Only 2% of people can actually understand as well as write code. A far greater number can write code but don’t understand it. India is full of very talented code writers with little understanding, and still only 2% of them can understand it.

This is why software, especially web pages and apps, are so abysmal.

Reply to  Zig Zag Wanderer
November 7, 2021 3:17 pm

I never write any program I don’t understand.

I only understand a few, simple programs someone else wrote!

November 5, 2021 10:02 pm

Another very good article in the Sydney Australia Daily Telegraph written by Vikki Campion.

It ends with: “Australia led a solid bloc of countries with Japan, Korea, India, Brazil, China and Indonesia to delete extreme pledges from the final communique (COP26), including a timeline on zero coal, signing up to a methane pledge and ceasing fossil fuels.”
“Even net-zero by 2050 was removed in the end to be in favour of net-zero ‘by or around mid-century’.”

“But in the end, Australia’s presence was slammed by the climate-Antoinettes, representatives from Hollywood, art galleries, climate renewable energy and environmental groups.”

“You will never make the climate-Antoinettes happy with any goal or commitment – not even when you are blaming your penis size on climate change.”

Zig Zag Wanderer
November 5, 2021 10:17 pm

Does environmental stress drive migration?


I migrated from the stress of living in a cold environment to live in a warm environment. Cold is nasty! Warm just requires a cold beer and a pool.

Reply to  Zig Zag Wanderer
November 7, 2021 3:19 pm

Cold living is clean. It is also bland.
Warm living must accomodate bugs, spiders, rats, mice and others ALL YEAR ROUND!

November 5, 2021 10:35 pm

“And regardless of the level of income involved, gross national income was the key factor in explaining net-migration in half of countries,’ says Venla Niva, a doctoral student at Aalto University and lead author of the study published in Environmental Research Letters”

People leave to better themselves. Who knew?

Rory Forbes
Reply to  lee
November 5, 2021 11:41 pm

The best way to succeed in science, when one has no aptitude for the real thing, is to ask questions for which the answers are obvious.

Tom Abbott
Reply to  Rory Forbes
November 6, 2021 8:40 am

Hey Rory, an antiviral to treat the Wuhan virus has just been authorized for use in the UK:

Pfizer is asking for approval for its new antiviral drug against the Wuhan virus and hopes to get approval by the end of November.

They are claiming if one gets infected with the Wuhan virus, taking these antivirals will prevent 90 percent of serious infections and keep most people out of the hospital.

All of a sudden, the news media is touting therapeutics as the solution to the Wuhan virus plague. Too bad they didn’t get on the therapeutics bandwagon a year ago with Hydroxycholoriquine and Ivermectin.. Thousands of lives would have been saved.

One conservative commentator this morning called the new Pfizer antiviral “Pfizermectin”. 🙂

Let’s just hope Trump doesn’t have anything positive to say about these new drugs, otherwise, the Elites will make them unavailable like they did with Hydroxycholoriquine.

So you now have an official alternative to a vaccination. If you get sick with Wuhan virus, just pop one of these pills in your mouth, and you’ll be done with the virus in a few days.

Just make sure to take any therapeutic as soon as possible after infection is detected. The sooner you get that virus out of your body, the better.

Rory Forbes
Reply to  Tom Abbott
November 6, 2021 10:23 am

Thanks for your concern, Tom. It sounds like at least someone is trying to do the job that the medical profession has been failing at by going along with the government policies.

Here in Canada they have been gaslighting therapeutics and all alternative treatments from the beginning. I saw the new UK antiviral drug on the news last week. It seems hopeful … but I’m pretty sure they’ll drag their feet on it as long as they can. They’re all in with the jab.

A big problem here is the large number of family doctors who have torn up the Hippocratic Oath and have gone virtual out of fear. People aren’t getting the sort of hands on medical treatment that detects early infection. It’s a death sentence for many people where early detection is important.

Only time will tell what my direction will take. After nearly two years I’m guessing that I have already been exposed.

Reply to  Tom Abbott
November 7, 2021 3:26 pm

The drug companies are seeking to develop other monclonal antibodies to generate big, government-covered new ones with similar high prices paid by the government. A racket, of sorts.

Nobody makes big buck from ivermectin or hydrovychoroquine.
They are stable, low overhead products. There is always malaria, fevers, and other diseases in the tropics.

November 6, 2021 12:20 am

‘Perhaps the most surprising finding from our study is that, when we look at the overall picture, social factors are more important than environmental factors in explaining migration.’

Can I just say duh?

Reply to  DaveW
November 6, 2021 5:59 am

Even more surprising, DaveW, they found that water is wet. Who knew?

Joao Martins
Reply to  DaveW
November 6, 2021 7:54 am

Yes, it is most surprising to those kids who were brain-washed in high-schoool with all the climate change garbage. I see around me, for them there is no society, there is no politics, they do not vote (what for?, they ask), only the marvels of nature exist (spending several days a year climbing mountains and walking and camping in natural parks, that is cool!), the achievements of mankind are boring and old stuff (who goes to a museum or visit a 700 years old cathedral?) and, as REAL problems, they only know the poisoning of bees and food by large scale agriculture (think of those neonics that kill all bugs! think of glyphosate!), the malefic effects of cattle raising (you know, like, forest burning… like, that methane thing, etc.) and the climate change catastrophe that they think they experience everyday.

November 6, 2021 1:42 am

It’s very obvious people are roaming the globe searching for sustainaBillity-
Bill Gates on ‘climate crusade’ on ‘one of worst polluting forms of transportation’ (

November 6, 2021 1:59 am

So, what makes migrants flee from France (EU) to the UK?

It isn’t the weather

Richard Page
Reply to  fretslider
November 6, 2021 9:18 am

2 reasons – the UK has (or had, at least) more opportunities to make money and France has the French.

November 6, 2021 2:51 am

Does environmental stress drive migration?
Yes! In the northern hemisphere, as the weather gets colder, and the leaves begin to change, migrating birds begin their first leg enroute to the warm, sunny south. They do this to escape the stress of living in the cold, snowy north country.

November 6, 2021 2:56 am

Climate-change as a driver of migration?

IF that is true THEN we should see changes in the pattern of all migratory species, as well as humans..

The consequence is that changes in migration patterns are a means of determining the scale of climate-change.

Can any readers point to changes in migratory behaviour of e.g. bird populations?

Peta of Newark
November 6, 2021 3:24 am

How’s about a migration where nobody (physically) goes anywhere?

Where people remove their minds from where they are but their bodies stay put – e.g. on the sofa.

Because that is what ‘drugs’ are all about = escape from a reality that the ‘drug’ user doesn’t like, feels threatened by & stressed’
The most significant stressor for humans is simply = loneliness..
Check out Gabor Mate’s book “Realm of Hungry Ghosts’

A very noteworthy thing he realised and noted after years of working with addicts was why they took drugs or especially what happened at the moment/instant the ‘drug’ kicked in.

The huge majority likened it to someone giving them a greaaaaat biiiiiiig super-tight hug, while whispering in their ear “It’s alright, everything will be OK now you’re here

There are your migrants
How do you count them, how do you know who they are?

For The Vast Majority, you know me, they are ‘simply’= Obese and also typically, addicted to TV

Now lets count the migrants – I see well over 250 million in the US alone

Another way to count or quantify them is via the money they spend on healthcare. ‘Drugs’ are not especially toxic but the problem with humans is Homeostasis.
The Brain adapts to the drug and requires ever greater amounts to achieve the ‘same size hug
Therein lies the very real danger

Will you or will you not require a Supercomputer to do the counting?

Take care, computers are addictive – they can tell you ‘everything is OK’ just as readily as not

Sure as eggs are eggs, there will be folks lapping up whatever the message. Good or Bad
As We All Know and witness on these pages daily..

again, take care out there, there be tigers, crocodiles & sharks – and – honey traps

November 6, 2021 4:58 am

It does not take a super computer and AI to figure out the obvious thing that humans migrate to other places to enjoy a better life for themselves and their families… DUH!

Better includes avoiding political oppression, social persecution, getting away from cold winters (!), finding higher incomes and standards of living, better health care, and the like.

The notion that any significant numbers of humans are migrating to get away from a warming climate is put to rest with the numbers. Here in Florida, with one of the hottest climates in North America, we have increased our population by about 3 million since the 2010 census, while nearly all of the northern tier states have suffered population decreases since then. People don’t flee warm climates, we flee cold climates.

Old Goat
November 6, 2021 5:10 am

My migration to France was driven by the plunge into the toilet of the Former UK…

Shoki Kaneda
November 6, 2021 8:06 am

I understand that the stress of shoveling driveways has forced many Americans to migrate south. So, yes.

November 6, 2021 11:06 am

Strangely, none of the flocks of geese and ducks which I’ve encountered seem to give a crap about anything other than the following:

  • Is there open water for swimming and safety from predators like Hoomans and coyotes?
  • Is there edible material available when we get there from here, or do we have to rely on Hoomans to throw stuff at us?’
  • How many coyotes and foxes and cougars are in the neighborhood we’re heading toward?
  • How many Hoomans with ballistic weapons will we find along those flight paths that we’ve been following for lo, these many thousands of years?
  • Is there adequate shelter and/or open water that we can rely on to have shelter from storms?
  • How many factories belching noxious gases are located in our flight path, whether warm-spot-bound or homeward bound?
  • If we don’t feel like leaving in the Spring, do we have to?

Essentially, migratory flocks have greater concerns than Hoomans, especially when the migration routes cross airports that used to be open land, and there is no bulletin for them to advise whether or not food resources are available along the way and/or when they reach their destination.

Walter Sobchak
November 6, 2021 8:04 pm

Welfare payments drive migration. The poorest people in the USA live like kings compared to most people in Haiti. If they can get here and get on welfare, that is like winning the PowerBall. Climate has nothing to do with it.

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