A new study by researchers at the University of Arizona and recently published in PNAS , concludes that one in three species of animals and plants could disappear in 50 years if warming is not reduced.
To reach this conclusion, the researchers have combined existing information on current extinctions due to climate change, the rates of movement carried out by species to escape rising temperatures, and future climate projections under consideration.
Cristian Román-Palacios and John J. Wiens, both from the Department of Ecology and Evolutionary Biology at the University of Arizona, have analyzed data from 538 species and 581 locations around the world to estimate future extinction rates. More specifically, they have studied local extinctions that have already occurred, based on studies of repeated surveys of plants and animals over time. Román-Palacios and Wiens generated climate data from the first survey to the last. What they found was that 44% of the 538 species had already become extinct in one or more places .
“By analyzing the change in 19 climate variables at each site, we were able to determine which variables drive local extinctions and how much change a population can tolerate without going extinct,” said Román-Palacios. “We also estimate how quickly populations can move to try to escape rising temperatures. When we put together all of this data for each species, we can get detailed estimates of global extinction rates for hundreds of species of plants and animals.”
Researchers have concluded that annual maximum temperatures are key to knowing whether or not a species will become extinct. However, it is the average annual temperatures, not the maximum, that are most often used as indicators of climate change. The scientists point out that using the latter provides extinction data that can be misleading since they have been seen to show smaller changes at sites with local extinction.
Seeking to escape the rise in temperatures, the animals migrate to colder habitats. However, those responsible for the study argue that, seeing the rates of movement that occurred in the past, most species will not be able to disperse fast enough to avoid becoming extinct.
Many species are able to tolerate a rise in temperature, but up to a limit. It has been found that about 50% of species became locally extinct if maximum temperatures increased more than 0.5 degrees Celsius, and 95% if temperatures increased more than 2.9 degrees Celsius. From this it follows that if the temperature trend is to continue growing, more species will become extinct.
“If we stick to the Paris Agreement to combat climate change, we may lose less than two in 10 species of plants and animals on Earth by 2070. But if humans cause further increases in temperature, we could lose more than a third or even half of all animal and plant species , according to our results, “said John J. Wiens.
Regarding the areas that would be most affected by extinctions, experts predict that they will be two to four times more common in the tropics than in temperate regions, a big problem since it is precisely in these areas where more species of plants and animals are given.
Fuente: Recent responses to climate change reveal the drivers of species extinction and survival, Cristian Román-Palacios, John J. Wiens Proceedings of the National Academy of Sciences Feb 2020, 201913007; DOI: 10.1073/pnas.1913007117
