The reason for migration in early human: malaria
Global Threads with Peter Frankopan
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The reason for migration in early human: malaria
Peter Frankopan<br>Jun 24, 2026
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As you will know if you’ve been following here for a while, I am interested in the history of disease and how this serves as a driver of change in human societies (I wrote a lot about this in The Earth Transformed).<br>One of the motors that has clearly been powered by pathogens and the expansion of disease envelopes is migration: over tens of thousands of years, humans have sought to live in places that are environmentally benign - where heat is manageable, water plentiful enough to sustain the population (and so on).<br>Global Threads with Peter Frankopan is a reader-supported publication. To receive new posts and support my work, consider becoming a free or paid subscriber.
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I am writing this as temperatures in the UK are threatening to touch 40° C: even those lucky enough to have air conditioning recognise that there are risks that come with exposure to heat.<br>I’ve worked ‘Garden of Eden’ locations in global history - Mesopotamia, for example; the Indus valley; oases in Central Asia and more - to look at what conditions made the rise of cities possible and (in many cases) spurred their decline.<br>One thing that seems obvious is that when it comes to migration in the pre-modern age, people moved in response to climate - to shifting rainfall patterns, identifying ideal vegetation distribution, adapting to shifting ecological zones.<br>But it is also obvious that people move away from locations that harbour disease.<br>While biting my nails in front of the World Cup games last night, I read a new paper that focuses on just this subject. Research led by Margherita Colucci of Max Planck, Jena and colleagues from Europe, the US and Africa argue that disease was not just a significant factor in driving human migration - but central driver.<br>One cannot understand human history without understanding migration, disease and malaria.<br>The study reconstructs the potential distribution of Plasmodium falciparum malaria across sub-Saharan Africa over the past 74,000 years. The authors start not with which ecological niches were most suitable for humans; but those that were ideal for mosquitoes - especially Anopheles gambiae, Anopheles funestus, and coastal species such as Anopheles melas.<br>Using pioneeting new palaeoclimate data, they generate what they call a ‘malaria stability index’ - which serves not to measure actual cases of malaria (which we cannot know) but of how suitable conditions were for sustained transmission (which we can).<br>The results are striking.<br>Across the period from 74,000 to 5,000 years ago, areas with high malaria stability consistently show low suitability for human occupation. In other words, early human populations did not simply expand into all and any climatically viable region. Rather, they avoided areas where malaria risk was high.<br>(Or, if they didn’t avoid them, they and/or their descendants didn’t survive).<br>This is not a marginal effect.<br>The researchers compared mosquito zones where these insects thrived alongside places where humans lived.<br>Areas occupied by the latter consistently had low malaria risk - in a pattern that held for tens of thousands of years.<br>The findings suggest that malaria was not just a health problem: it helped shape where people chose to settle and live - and (just as importantly) were instrumental in the creation of trade and communication corridors (and thus for ecological adn genetic diffusion too).
The research also throws up some other interesting questions.<br>For example, the model shows an early peak in malaria stability around 60,000–50,000 years ago, coinciding with the main ‘Out of Africa’ dispersals.<br>This raises the possibility that populations leaving Africa did so not only under climatic pressure, but also from landscapes where malaria risk was already significant.<br>It is possible too that humans on the move did something else too - namely carrying the malaria parasite with them, expanding the envelope that mosquitoes thrived too.<br>There seems to have been a second, even more pronounced expansion in high-risk zones occurs after the Last Glacial Maximum (around 13,000 years ago).<br>What is important here is timing.<br>Malaria became a serious threat thousands of years before the first farmers began growing crops. That challenges the common idea that malaria only became important once people settled in villages and started farming: in fact, it seems that malaria was shaping human evolution and influencing where people could live long before agriculture changed the landscape.<br>I worked too on the importance of genetic mutations and immunities in my book (sorry to mention it again) - both in terms of Bantu migrations, but also on the horrific role that genetic advantage played in trans-atlantic slavery and in racism: many enslaved people were racially ‘superior’ to slave owners...