CLIMATE CHANGE is threatening the survival of plants and animals as temperatures rise and habitats change. Some species have been able to meet the challenge with rapid evolutionary adaptation and other changes in behavior or physiology. But scientific studies show that climate change is occurring much faster than species are changing.

All over the world, plants and animals have adapted to many different warm and dry habitats, making scientists question whether species might also adapt to our rapidly changing climate, too. The answer seems to be NO for most species.

A study of the populations of 19 bird and mammal species, including owls and deer, shows one potential barrier to adaptation.

In animals that take several years to reach breeding age, the climate has already shifted by the time their offspring are born. Genes that gave the parents an advantage – like hatching at exactly the right time or growing to the best size – are no longer as beneficial for the offspring.

Populations of these slow-maturing animals are adapting to climate change, but not enough during each generation to thrive in the changing conditions. In fact, the rate of evolution is so mismatched to the rate of global warming that the researchers estimate that nearly 70% of the local populations they studied are already vulnerable to climate-driven extinction over the coming decades.

Cold-blooded species, such as lizards, frogs and fish, are especially vulnerable to climate change because they have a limited capacity to regulate their own body temperatures. Their ability to evolve in response to climate change is expected to be critical for their survival.

Rapid adaptation to climate change often comes at a cost. Populations get smaller due to the deaths of individuals that cannot tolerate new, hotter temperatures. Thus, even if species do evolve to survive with climate change, their smaller populations may still go extinct due to problems such as inbreeding, harmful new mutations or  bad luck, such as a disease epidemic.

Another way species adjust to rising temperatures is acclimation, sometimes called “phenotypic plasticity.” But a recent analysis of more than 100 beetle, grasshopper and other insect species all over the world found that acclimation may not help those species enough. And the rate of global warming seems to be outstripping abilities of species to acclimate also.

Overall, evolutionary adaptation appears to lessen the impacts of global warming, but the evidence thus far shows that it is insufficient to overcome current rates of climate change. Acclimation and migration provide faster solutions, although research shows that those may not be enough.

Not all evolution is driven by warming temperatures. Plant and animal species appear to be also gradually adapting to other kinds of environments, including human-created ones like cities. But the fast pace of global warming makes it one of the major threats that species must respond to immediately.

The evidence indicates that humanity cannot simply assume that plants and animals will be able to save themselves from climate change. To protect these species, humans will have to stop the activities that are accelerating climate change. By Manny Palomar, PhD (EV Mail Feb. 19-25, 2024 issue)