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Animals in Extinction Due to Global Warming

The Earth has undergone five mass extinction events to date; however, the sixth one is likely to be caused by human activity. There are serious concerns about global warming and its effect on the environment, including climate change, introduction of invasive pathogens and destruction of natural habitats. These effects put many plant and animal species at risk of extinction, although insufficient evidence exists as to how long and to what extent these events will take place.

  1. Deforestation Linked to Extinction

    • Deforestation is the main contributor to global warming and animal extinction, via increased greenhouse gas emissions and habitat destruction. Tropical rain forests harbor many of the world's plant and animal species, and deforestation jeopardizes their survival. It also causes less rainfall as tree roots extract water from the soil and return it to the atmosphere, leading to drier conditions, which alters the ecological environment of many species.

    Amphibians

    • In 1988, the Monteverde Golden Toad of Costa Rica was classified as extinct, and scientists attribute that to global warming. It is believed that temperature rises due to increased greenhouse gas emissions from deforestation of lowland tropical forests created the environment for the growth of the deadly fungus Batrachochytrium dendrobatidis, leading to the disease called chytridiomycosis and eventually death. Such conditions also threaten other amphibians; over 43 percent of amphibian species face population decline and extinction.

    Polar Bears

    • Polar bears live exclusively in the ice-covered Northern emisphere marine areas, and rely on sea ice for access to food sources. Global warming significantly reduces ice cover, and should the global mean surface air temperature (GMAT) be exceeded, this ice cover, along with habitats of other cold-dependent species, could permanently disappear. According to the U.S. Geological Survey, if greenhouse gas emissions continue at the current rate, two thirds of polar bears would be lost by the middle of the 21st century.

    Lizards

    • Lizards such as the Sceloporus species are heliotherms, meaning they require heat energy to maintain body temperatures and conduct physiological processes. This should make them resistant to global warming effects; however, most lizards die when body temperatures exceed the critical thermal maximum temperature. Lizards seek refuge in cool places during extreme heat. Excess time spent cooling restricts metabolic activities such as growth and reproduction, and also limits food access, thus hindering population growth and increasing extinction risk. In Mexico, 12 percent of the local lizard population has gone extinct since 1975.

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