If Extinction Is Natural, Why Should We Worry?
It is sometimes said that extinction is a natural process, and therefore nothing to be alarmed about. Indeed, throughout the long history of life, countless species have appeared and then disappeared, and mass disappearances have even occurred in the distant past, long before humans existed, and the living things we see today are only a small portion of those that have ever existed. From this fact, some people conclude that efforts to protect endangered species amount to a futile attempt to resist nature.
The first half of this argument is correct, but the conclusion does not follow. What matters is not that species disappear but the speed at which they do so. Natural extinctions usually unfold over very long periods, during which other organisms have time to adapt, to evolve, and to fill the space left behind. When human activity, such as the destruction of habitats or the spread of species into new areas, removes many species within a short span, the ecosystem loses the time it needs to recover. To say that both processes are “natural” is to ignore this crucial difference in pace.
There is also the matter of interdependence. Organisms are connected through webs of feeding, pollination, and shelter, so the loss of one species may affect many others in ways that are hard to predict. A predator that vanishes may allow its prey to multiply and strip the vegetation; a plant that disappears may leave the insects that depend on it without food. Because these chains of effects are complex, the damage often becomes visible only after it has become hard to reverse. Ecologists therefore describe biodiversity as a kind of insurance, which helps living communities to withstand sudden changes.
Some critics raise a practical objection: resources for conservation are limited, and money spent on a small, unattractive creature might be better used for human needs. This concern is not unreasonable. Yet protecting habitats, rather than single species, often benefits people as well, since forests, wetlands, and coastal areas provide clean water, protection from floods, and food. Moreover, protecting a healthy habitat is usually cheaper than trying to repair one after it has been damaged. In such cases the choice is not between nature and humanity.
Thus, the statement that extinction is natural is true but incomplete. The pace, the interdependence, and the human role all change how we should judge what is happening. Accepting change in nature does not require us to accept every loss that we ourselves have caused.
※この英文は原田英語のオリジナルです。