Causes and effects of climate migration: Five essential insights

A key takeaway from Wellington’s work with Woodwell Climate Research Center is that climate change will likely lead to climate migration, with considerable social, economic, and geopolitical consequences. We set out to research the causes and effects of structural climate migration in detail. What aspects of climate change may drive people to permanently leave their homeland? Where will they go? How will climate migration affect outbound and inbound regions? And finally, what are some of the investment implications across regions and industries? In this paper, we share our insights on this complex, long-term issue.

1. Permanent changes in livability are principal drivers of climate migration

We believe permanent, chronic deterioration in livability is the primary driver of climate migration. In many parts of the world, climate change is contributing to — and exacerbating — declining livability. Gradual temperature increase is the biggest factor, while other slow-onset changes, including drought conditions and sea-level rise, can also be material. We found that while acute climate events like hurricanes or floods may result in temporary displacement as a region recovers, they are unlikely to lead to permanent migration unless their occurrence becomes a pattern, in combination with slow-onset changes. These include repeated flooding or storm surges as a function of rising sea levels, for example, or more frequent wildfires caused by perennially hotter, drier conditions. As the US defense community has noted, climate change alone does not drive outbound migration. By amplifying underlying political, economic, or social tensions, climate change can become a threat multiplier — a livability tipping point that helps catalyze an exodus. For example, Syria’s mass migration was a direct consequence of civil war brought on by decades of dictatorship and repression. In addition, persistent drought conditions caused agriculture yields to collapse and food prices to skyrocket. These stresses, compounded on the middle and lower classes, may have accelerated the escalation to physical conflict and emigration. More broadly, rising temperatures have been shown to negatively correlate with per capita income, labor productivity, health and mortality, political stability, civil cohesion, and crime rates.¹ These factors can all be catalysts for migration away from a troubled region. We conclude that if people perceive their long-term economic and/or personal security to be at risk in part because of climate change, they are more likely to move away for good.

2. Climate migrants prefer to remain close to home, but transnational moves are possible

Our research revealed that most climate migrants will aim to relocate within affected countries’ borders, preferring to remain as close to family, culture, and social networks as possible. One important caveat is a phenomenon called “stepwise migration,” where migrants make incremental adjustments in the process of their long-term resettlements, again, to minimize personal disruption each time. Researchers for a recent study by The New York Times Magazine and ProPublica found that for climate migrants: “It’s only when those [new] places fail them that they tend to cross borders, taking on ever riskier journeys.”² Migrants who do exit their country may leave a spouse and other family members behind, preferring to minimize the disruption and send financial assistance home.

Within regions subject to climate change, people are not affected equally. Higher-income individuals may have a broader range of options and defense mechanisms. They may be able to remain at home and adapt, adjusting living and working conditions with cooling systems for homes and offices, swimming pools, or frequent travel. At the other end of the income spectrum, people with the fewest resources may be…

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¹“The slow onset effects of climate change and human rights protection for cross-border migrants,” Annual report of the United Nations High Commissioner for Human Rights and reports to the Office of the High Commissioner and the Secretary-General. March 2018. | ²Lustgarten, Abrahm, “The Great Climate Migration,” The New York Times Magazine, in partnership with ProPublica, July 2020.