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FUTURE HUMAN
Will Climate Change Remake Human Biology?
We may not be able to sweat our way through the heat
In 1980, a nuclear power plant in Forsmark, Sweden, began pumping cooling effluent from its reactors into “Biotest Lake,” a manmade, 84-hectare enclosed body of water jutting out from the Baltic Sea. Separated from its aquatic environs and featuring a habitat that was consistently some six to 10 degrees Celsius warmer than the surrounding Baltic, the lake provided, as one group of researchers put it, “an unprecedented model to examine the long-term physiological responses of temperate fishes facing a severe climate-warming scenario under ecologically realistic conditions.”¹
Some native species quickly disappeared from Biotest Lake,² while others persisted. The European perch, in particular, proved remarkably resilient. But it became clear that it was not the same fish it used to be. Biotest perch had apparently undergone some degree of genetic selection and physiological adaptation: These fish were larger than control specimens, had smaller organ masses, and, crucially, had a lower resting heart rate than control fish placed in a warmed environment.
The popular imagination, when thinking about climate change impacts, often focuses on sea-level rise and how coastal dwellers will adapt. The poster for the Hollywood disaster film The Day After Tomorrow shows the torch of the Statue of Liberty rising from the sea. Kim Stanley Robinson’s novel New York 2140 imagines a submerged Gotham in which the rich live on safe upper floors of Manhattan skyscrapers.
But heat may be the bigger story. Climate scientists Steven Sherwood and Matthew Huber point out that “if warmings of 10 degrees Celsius were really to occur in next three centuries, the area of land likely rendered uninhabitable by heat stress would dwarf that affected by rising sea level.” Heat stress, scientists argue, “deserves more attention as a climate change impact.” There are already projections that some places in the Persian Gulf could be, without “significant mitigation,”³ virtually uninhabitable by the end of the century. A paper by Alistair Woodward, head of epidemiology and biostatistics at the University of Auckland, and his colleagues projects that by 2085 only a handful of cities…
