Biodiversity

Biodiversity describes the abundance, variety, and genetic constitution of native animals and plants. The term "biological diversity" was first coined by conservation scientists Thomas Lovejoy and Robert Jenkins. Another definition that is often used by ecologists is "the totality of genes, species, and ecosystems of a region."¹

Bufo periglenes - the golden toad. This species' extinction has been attributed to climate change.

Credit:Charles Smith, US Fish and Wildlife Service

Climate change is expected to drive biodiversity loss and species extinction. In terms of extinction rates, a recent analysis projects that 15-37% of a sample of 1,103 land plants and animals would eventually become extinct as a result of expected climate changes by 2050.²   For some species, there will no longer be anywhere suitable to live. Others will be unable to reach places where the climate is suitable.³   Climate change's impact on plant and animal communities can be unexpected and at times dramatic: each species responds differently according to its climate tolerances, its ability to relocate, alter its breeding period, or shift food sources. Marine species will be particularly hard hit by ocean acidification, a change driven by the increased concentrations of carbon dioxide in the atmosphere. Ocean acidity is worrisome because tens of thousands of marine species build shells and skeletons from calcium carbonate. The more acidic the water, the more difficult it is for organisms to mobilize calcium carbonate.⁴

Climate change will impact plant, animal, and marine species in all parts of the world. In Australia, for example, there is evidence of increased numbers of snow gums growing in sub-alpine meadows in the Australian alps, coral bleaching, and the intrusion of freshwater swamps by mangroves.⁵

In Africa, typical migrations of mammals, such as rhinos and elephants, involve regular movement between dry-season and wet-season grazing areas and are therefore sensitive to climate change. Biodiversity hotspots such as the Cape Floral Kingdom (Southern Africa) are home to 7,300 plant species and the Succulent Karoo biome contains an additional 4,000 species, of which 2,500 are native.⁶   These two main biodiversity hotspots occur in winter rainfall regions and would be significantly threatened by a shift in rainfall patterns.

The Latin American and Caribbean region contains nearly half of the world's diversity of plant and animal species and half of the world's tropical forests. Global warming is expected to have a detrimental impact on the rate of destruction of freshwater, marine and forest habitat—a result expected to profoundly impact biodiversity in the region. Brazil's Amazon Basin contains a large portion of the world's biodiversity: at least 40,000 plant species, 427 mammals, 1294 birds, 378 reptiles, 427 amphibians, 3,000 fish, and over one million insect species have been identified. Climate change threatens to substantially affect the Amazon, which in turn is expected to increase the risk of biodiversity loss.⁷

Fortunately, there are a number of positive measures/initiatives that can be implemented to buffer natural systems against climate change. One measure is to reduce additional stresses on ecosystems so that they do not reinforce the climatic changes taking place. For example, by reducing siltation on coral reefs. Another is by implementing adaptation strategies in response to sea level rise--strategies which can anticipate sea level rise and facilitate the development of new freshwater wetlands as current ones become tidal. And finally, the expansion of the world's protected areas will be an important strategy, as they provide a safe haven where species can move to new locations.⁸