Humans have a shameful record of driving species extinct. The dodo bird was one of the first documented human-caused extinctions. The Labrador duck and passenger pigeon soon followed. And we may be well on our way to eliminating the Pacific blue-fin tuna. Current extinction rates, largely driven by humans, are between 100 and 1000 times greater than rates seen in the geologic record.
Nearly all human-caused extinctions stem from ignorance or greed with respect to nature. No one sat down and decided that it was time to drive the passenger pigeon off the face of the Earth by mass shootings of its flocks. We did it for fun in blind ignorance of how our actions might play out over time. Extinctions driven by the delivery and proliferation of exotic species also reflect our ignorance of species interactions and how nature works. Extinctions driven by ongoing changes in Earth’s climate are due to similar inattention to our actions.
Ignorance and greed are hardly good excuses for our past behavior, but now we are also realizing the capacity to intentionally eliminate species from the surface of the Earth.
The design and release of genetically modified male mosquitoes that will breed with local, native females to produce only male offspring could likely result in the elimination of these mosquito species locally, if not globally. We might herald such activity for species such as Aedes aegypti, which carry a variety of human disease vectors. Mosquitoes that carry malaria are also prime candidates for management. In these cases, one might argue that these “gene drives” are more effective and less harmful to nature than the continued use of broad-spectrum and persistent insecticides such as DDT, which environmentalists have abhorred for decades.
But, when it comes to human mastery of nature, who makes the decision about which species go extinct and which persist? One might envision arguments to eliminate crows, cormorants, house flies, and red-winged blackbirds—each of which has a current, vocal advocacy for its elimination. Will we appoint an international tribunal for the mastery of nature to decide who survives and who does not?
Each of these species has a role in nature, which is often poorly understood. Past studies suggest that when we reduce or eliminate predators, there are often unexpected and costly consequences for the rest of nature and humans. Witness the loss of wolves from the eastern U.S. and the subsequent proliferation of white-tailed deer, much to the displeasure of auto insurance companies. Who will decide what level of scientific study could justify the elimination of a species with impunity?
Mosquitoes feed swallows, frogs and bats. If you suffer from malaria, dengue, yellow fever or zika, you may not care about the higher trophic levels that depend on mosquitoes. But we should not suppose that the disappearance of species will be of no consequence to others, including us.