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Meta-analysis of current global warming impacts suggests a third of all species could be extinct by 2100

A biologist at the University of Connecticut has found evidence that up to a third of all species alive today could go extinct by 2100 if greenhouse gas emissions are not slowed or stopped. In his study in the journal Science, Mark Urban conducted an analysis of 485 studies carried out over the past 30 years on the ability of species to adapt to climate change.

Manmade greenhouse gas emissions are causing atmospheric and seawater warming, and these temperature increases will lead to unpredictable weather changes—besides growing warmer, it is expected that some places will grow wetter and others drier.

It is also likely that the world will see more extreme weather, such as droughts, hurricanes and typhoons, in addition to thunderstorms or snow storms. Such changes will put pressure on species that are not able to control their environment the way humans do, putting many at risk.

In this new effort, Urban found 485 papers that involved the study of a species and its ability to survive changes to its environment. He then compared this data with estimates of future warming and determined what sort of changes might occur and in which areas. He then made estimates about the likely survivability of a given species based on where it lives and its ability to migrate or to adapt.

He found that if global temperatures rise approximately 5.4°C by the end of this century (the worst-case scenario), it would likely lead to the extinction of approximately one-third of all species alive today. He notes that some cases of chain-reaction extinctions could occur, in which a small animal goes extinct and then a larger animal that feeds on it consequently goes extinct. He also notes that some species groups or types are at much higher risk than others, such as amphibians.