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8.1: Doom and Gloom

we must acknowledge, as it seems to me, that man with all his noble qualities, with sympathy which feels for the most debased, with benevolence which extends not only to other men but to the humblest living creature, with his god-like intellect which has penetrated into the movements and constitution of the solar system—with all these exalted powers—Man still bears in his bodily frame the indelible stamp of his lowly origin. [Darwin 1871:405]


The word overpopulation is very subjective. There is no scientific way to decide how many people is too much. It is more of an aesthetic question: like would you prefer to live in a huge mansion all by yourself, or in a one-bedroom apartment with 10 roomates? Most people would choose something in between, probably leaning towards the mansion. The science of population change is called demography, literally a "map of people/districts", and the science has mapped a population explosion in the last eye-blink of human evolution. We are rapidly heading towards the one-bedroom apartment with 10 roomates, and the ensuing drama is taking place on a global scale.

Loss of Biodiversity

Should we care about any other species besides our own? This question is like asking "Should I care about anyone else besides myself?" on a larger scale. Most people care about at least some of their family members. Through the genealogical emphasis of anthropology, many people can extend their altruism to include broader categories of people they're not related too, people of different "races", and hopefully other species.

To me biodiversity is an aesthetic question. Complex ecosystems are beautiful. Do you want kids to grow up in a world where the only other life they know is cockroaches, mosquitos, rats, and pigeons? Review the section on primate extinction

Global Warming

If you compare a graph of population growth and average temperature you can see the correlation between human overpopulation and climate change. How much CO2 was produced by 6,000,000 (6 million) hunter-gatherers sitting around campfires? Almost nothing! That's about the equivalent of one campfire every two hundred square miles. How much \(\ce{CO2}\) is produced by 6,000,000,000 (6 billion) people who are driving, consuming, deforesting? Our ecological footprint is massive compared to our hunter-gatherer ancestors, and there are thousand times more of us.

We should expect both massive extinction and some evolution as variations in populations are selected for in the new ecological niches caused by extreme weather, drought, flooding, acidification of the oceans. Global warming will cause more people to die of starvation and infectious disease. Many plants and animals will go extinct, humans will use cultural adaptations to survive, but it will be very painful and expensive, and the longer will put our heads in the sand and ignore the problem, the worse it will be.


Figure \(\PageIndex{1}\)


Comparing human caused extinction to other mass extinctions

An economic approach, the environment as an “externality”


Geological periods are usually bracketed by climate change and major extinction, and they are based on empirical evidence that a geologist with a rock hammer can go out and find. Human effects on the environment have begun to show up in the field of geology: