I’ve heard this anecdotally before (and may even have shared it, tongue-in-cheek, a time or two).
But in all seriousness, does climate actually affect worker mobilization or deployment? Here’s a broad climate map of the Earth: The “10/40 Window” spans from 10 degrees north of the equator to 40 degrees north of the equator.
In this area, we can see a large amount of Arid space (B) in North Africa and Western Asia.
There are few workers deployed there - but then, there are few people who live there.
Much of that big yellow space is the Saharan Desert.
There are far more workers (rightly so) in the little green spots north of the yellow (the densely populated North African coast) and the little orange band south of the Sahara (densely populated areas in West Africa). The terrain mix in the east is not unlike the terrain mix in Latin America, based on the broad strokes of this map, and a lot of workers have been sent to South America. Once upon a time it had a fatal effect; today, while death by disease is less common, still the climate can wear on workers and make life very difficult. Three of the five hottest places in the world are in the 10/40 Window.
Still, I am not entirely convinced climate has as much to do with mission deployment (or lack thereof) as other factors.
In “Why they don’t go: surveying the next generation of mission workers” (EMQ 4/2008, Thornton & Thornton), a “baker’s dozen” list of reasons for why this generation doesn’t go overseas was identified from a detailed survey of college students.
These included (1) pluralism, (2) the myopic US church (difficult to raise support), (3) the political climate, (4) selfishness and a lack of self-sacrifice (which Platt & TGC and others have been admirably taking on), (5) the family (young people hesitate to do anything which takes them away from loved ones–one person anecdotally told me that pastors rarely take on churches more than an hour’s drive from their wife’s family), (6) disconnect between local church and mission agency, (7) inadequate theology, (8) confused definitions, (9) inadequate preparation, (10) debt (becoming more and more a factor for students), (11) short-term missions (“done their bit for the Kingdom”; inoculation), (12) spiritual warfare, (13) emerging two-thirds world (“send the natives”).
In an earlier July 1996 article ("Why are the unreached, unreached"), Nik Ripkin pointed out a few other issues: (1) a harvest mentality (go only where the harvest is being harvested, not where the ground is difficult); (2) we know one way to “do church”, so don’t go to people who can’t do it that way (Somali nomad: “Show me how to put your church on my camel before you talk to me about your Jesus”), (3) security (“how do we promote and fundraise when we can’t talk about the work we’re doing”), (4) persecution, (5) ignorance and prejudice toward Christianity, (6) climate (“as the temperature climbed, the number of missionaries went down”–at least one anecdotal evidence for that), (7) it’s expensive, (8) high personnel maintenance.
In “What’s behind the wave of short-termers” (EMQ, 10/92), Leslie Pelt suggests that short-term is a test for long-term: “if the climate, language, culture and amenities are acceptable, then God might be leading them to extend their commitment.” So one acid test might be: how many short-termers go to hot climates?