PAST CLIMATE CHANGE often caused by natural changes due to volcanic activity has been responsible for mass extinctions of species on Earth. But it is not clear as to what factors cause species to be more or less resistant to such change, and how the extent of climate change affects extinction.
A study sought to answer this question by analyzing the fossil record for marine invertebrates – such as sea urchins, snails, and shellfish – over the past 485 million years.
Using over 290,000 fossil records covering more than 9,200 genera, the researchers examined a dataset of key traits that may affect resilience to extinction, including traits not studied in depth previously such as preferred temperature. This trait information was integrated with climate simulation data to develop a model to understand which factors were important in determining the risk of extinction during climate change.
Research showed that species exposed to greater climate change were more likely to become extinct. In particular, species that experienced temperature changes of 7°C or more across geological stages were significantly more vulnerable to extinction.
They also found that species occupying climatic extremes (for instance in polar regions) were disproportionately vulnerable to extinction, and animals that could only live in a narrow range of temperatures (especially ranges less than 15°C) were significantly more likely to become extinct.
But geographic range size was the strongest predictor of extinction risk. Species with larger geographic ranges were significantly less likely to go extinct. Body size was also important, with smaller-bodied species more likely to become extinct.
All of the traits studied had a cumulative impact on extinction risk. For instance, species with both small geographic ranges and narrow thermal ranges were even more susceptible to extinction than species that had only one of these traits.
The study revealed that geographic range was the strongest predictor of extinction risk for marine invertebrates, but that the magnitude of climate change is also an important predictor of extinction, which has implications for biodiversity today in the face of climate change.
With current human-driven climate change already pushing many species up to and beyond the brink of extinction, these results could help identify the animals that are most at risk, and form strategies to protect them.
Thus, future work should explore how climate change interacts with other potential drivers of extinction, such as ocean acidification and anoxia (where seawater becomes depleted of oxygen).
This study shows that the extinction risk of marine life has been inextricably linked to climate change. This should act as a warning to us as we continue to cause climate change ourselves through burning fossil fuels. By Manny Palomar, PhD (EV Mail JAN. 27- Feb. 02, 2025 issue)
