RAPID SPECIES EXTINCTION Like the other impacts of climate change, we need to examine the degree and rate with which species are going extinct due to climate change. Species have always gone extinct but climate change is increasing the speed and magnitude – dramatically. So much so, that many scientists refer to what is happening as the sixth great mass extinction – a period when many species go extinct due to rapid changes in the Earth’s ecosystem. This time, the rapid change is anthropogenic (originating in human activity) climate change and human-caused habitat loss. The figure below is from research that examines the rate of species extinction. They compare the current rate to the “background rate” (the rate of extinction expected based on rates of extinction over a much longer history). The extinctions that have actually occurred in the last 114 years, conservatively, should have taken at least 2000 years in most cases! Remember, extinction is forever. Hundreds of thousands of years of biological evolution wiped out. Scientists believe it took nearly 10 million years for the Earth’s ecosystem to recover from the last mass extinction.
The UN reports that 1 million species are currently at risk of extinction. Scientists estimate that there are 8 million plant, animal, and insect species on Earth. In a report authored by hundreds of authors from over fifty countries, the UN notes that “More than 40% of amphibian species, almost 33% of reef-forming corals and more than a third of all marine mammals are threatened.” Again, it is important to recognize the complexities. Rapid mass extinction is not ALL because of climate change, but it is all because of human-related activities. It is also caused by pollution, species exploitation (consumption), habitat destruction such as deforestation, and the introduction of invasive species.
Other stunning findings (pulled directly) from the report that demonstrate human impact:
- Three-quarters of the land-based environment and about 66% of the marine environment have been significantly altered by human actions.
- More than a third of the world’s land surface and nearly 75% of freshwater resources are now devoted to crop or livestock production.
- 60 billion tons of renewable and nonrenewable resources are now extracted globally every year – having nearly doubled since 1980.
- Negative trends in nature will continue to 2050 and beyond in all of the policy scenarios explored in the Report, except those that include transformative change
- The distributions of almost half (47%) of land-based flightless mammals, for example, and almost a quarter of threatened birds, may already have been negatively affected by climate change
For a list of the species declared extinct (not just due to climate change) in 2019 see this post:
While the impacts of climate change on human societies will be great, the impact on other species, combined with habitat loss, risks unprecedented, human-caused, mass extinction.
For more on endangered species due to all causes, see the film Racing Extinction (trailer below).