Biodiversity and the Effects of Climate Change

Biodiversity is the degree of variation of life forms within a given ecosystem, biome, or an entire planet. Biodiversity is a measure of the health of ecosystems. Greater biodiversity implies greater health. Biodiversity is in part a function of climate. In terrestrial habitats, tropical regions are typically rich whereas polar regions support fewer species. There are a few ways to assess the value of living organisms other than those from whom we derive direct benefits. One can look at the organism's intrinsic value. The intrinsic value of an animal refers to the value it possesses in its own right, as an end-in-itself, as opposed to its instrumental value, which is the value or worth that something has because of its usefulness.

Rapid environmental changes typically cause extinctions. One estimate is that less than 1% of the species that have existed on Earth are extinct. Since life began on Earth, five major mass extinctions and several minor events have led to large and sudden drops in biodiversity. Unexpected results may follow when climate conditions change. Each species will respond in an individual fashion, according to its climate tolerances and its ability to disperse into a new location, alter its breeding date or adapt to shifting food sources. It is difficult to predict the overall result of changes in the abundance of herbivores and food plants, predators and prey. The vulnerability of an ecosystem to climate change depends on its species' tolerance of change, the degree of change, and the other stresses already affecting it. For example, coral reefs already polluted by sediment and nutrient run-off may find it more difficult to survive increasing ocean temperatures. Another direct example of increasing temperatures is the pika, a rabbit whose hibernation is being cut short by earlier spring thaws. As a result of being exposed to unbearable early heating, these animals are running out of higher, cooler elevations to retreat to, and extinction threatens.

Another big player in the loss of biodiversity is extinction. The impact humans are having on organisms is comparable to that of the asteroid that struck during the Cretaceous era that cause many dinosaurs, including the ever-popular Tyrannosaurus Rex to become extinct. Our species has caused deforested, dredged, and polluted, among other things, to one-half of the earth. This, in turn, has caused a substantial and largely irreversible loss in the diversity of life on Earth. Examples of recent extinctions caused by humans include such well-known cases as the dodo, passenger pigeon, and great auk. Many other high-profile species have been taken to the brink of extinction, including the plains bison, whooping crane, ivory-billed woodpecker, right whale, and other marine mammals. These losses have been caused by insatiable overhunting and intense disturbance or conversion of natural habitats.

One more large cause of the loss of biodiversity is the introduction