Climate Change and Human Evolution
Daniel DeMarco

Very interesting. I hope you will tolerate a few very brief remarks from a non-scientist. Some will be simply to state features of my general view for background, and some will be mild objections to some of your “assumptions.”

I generally regard evolution in a broad sense as any change in an observable with time. I regard myself as a small perambulating ecosystem in the biological sense, and I am therefore concerned with the health and mutual interactions of all the different “organisms” inside and on “me.”

I believed in biological evolution by “survival of the fittest” when I was a child but rejected that notion in the second semester of my freshman introductory biology class in college. (During the first semester, while eating my sack lunch in the seminar room on the fifth floor of the Experimental Science Building at the University of Texas, I also audited an interesting seminar class on the history of genetics taught by Dobzhansky.) Unable to construct a satisfactory operational definition of “fit,” I modified my notion to “survival of the survivors.”

Humans continue to evolve biologically. I think the increase of lactose tolerance in the population over the last ~4000 years is one clear example. The spread of the Tay-Sachs gene in a subpopulation might be another example.

In general, I view the whole complex of interacting populations in a given environment as evolving together. This includes evolution of the environment. In other words, the total system evolves, which includes evolution of its component subsystems.

From such a standpoint, the question is not whether humans will evolve to survive the accelerating climate change but whether ecosystems will evolve that include humans as a component subsystem. In terms of environmental evolution, one rough historical analogue might be the Great Oxygen Catastrophe.