Concept
There are several plausible pathways that could lead to an increased extinction risk from climate change. This is because every plant and animal species has evolved to exist within a certain ecological niche, and as climate change represents the long-term alteration of temperature and average weather patterns, it can push climatic conditions outside of the species' niche, which will ultimately render it extinct. Normally, species faced with changing conditions can either adapt in place through microevolution or move to another habitat with suitable conditions. However, the speed of recent climate change is so unprecedented, that even under "mid-range" scenarios of future warming, only 5% of current ectotherm locations (a category which includes amphibians, reptiles and all invertebrates) are within 50 km of a place which could serve as an equally suitable habitat at the end of this century. Climate change also increases both the frequency and intensity of extreme weather events, which can directly wipe out regional populations of species. Those species occupying coastal and low-lying island habitats can also be rendered extinct by sea level rise; this has already happened with Bramble Cay melomys in Australia. Finally, climate change has been linked with the increased prevalence and global spread of certain diseases affecting wildlife. This includes Batrachochytrium dendrobatidis, a fungus identified as one of the main drivers of the worldwide decline in amphibian populations. So far, climate change has not yet been a major contributor to the Holocene extinction, and nearly all of the irreversible biodiversity loss to date has been caused by other anthropogenic pressures such as habitat loss or the introduction of invasive species. Yet, its effects are certain to become more prevalent in the future. As of 2021, 19% of species on the IUCN Red List of Threatened Species are already being impacted by climate change. Out of 4000 species analyzed by the IPCC Sixth Assessment Report, half were found to have shifted their distribution to higher latitudes or elevations in response to climate change.
