About the planet 1.3 degrees Celsius Warmer today than in the late 1800s. This seemingly small increase has affected the natural world in several profound ways. The birds have become smaller. Lizards, insects and The snail has changed color. Some goats have become more nocturnal. These are adaptations that help animals survive climate change.
Many species, however, have not been able to adapt quickly enough. Rising temperatures have not only decimated animal populations, such as wildlife-killing fires in Australia and the Amazon, but they have driven entire species to extinction. Several years ago, a The Australian rat is called Bramble Cay melomys Extinct, mainly due to sea level rise. Warming temperature Disease-carrying mosquitoes spread at high altitudes in HawaiiKill every last individual of certain bird species.
That is the situation today. It’s already dark. So what will happen to wildlife populations — or even more so when — the world gets warmer?
That urgent question is at the center of a new one StudyPublished in Journal science The study analyzes how different degrees of warming, relative to pre-industrial-era averages, affect the share of species worldwide that are at risk of extinction.
The numbers cited in the study are alarming, but they also underscore an important message: If countries can rein in their greenhouse gas emissions, they stand to save thousands of species from their permanent extinction.
Current climate policies put half a million species at risk of extinction
This new study is a meta-analysis, meaning it synthesized the results of other existing studies — 485 of them, to be precise. It estimates the percentage of known plant and animal species worldwide that may become extinct under different climate conditions in the future. These scenarios include current levels of warming and targets under the Paris Agreement, a global UN agreement to curb climate change, as well as more extreme emissions scenarios.
- 1.3 degrees (current temperature): 1.6 percent species
- 1.5 degrees (ambitious Paris Agreement goals): 1.8 percent species
- 2 degrees (Official Paris Agreement Goals): 2.7 percent species
- 2.7 degrees (where current policies and commitments get us): 5 percent species
- 4.3 degrees (High Emission Scenario): 14.9 percent species
- 5.4 degrees (a worst-case warming scenario): 29.7 percent species
Scientists still don’t have a firm idea of how many species there are on Earth, so it’s difficult to translate these percentages into actual numbers of extinct animals. Scientists now think there is 10 million species Or more, according to ecologist Mark Urban, the study’s sole author. This would lead to a projected loss of about 160,000 species under current warming, rising to half a million if the world fails to enact additional policies to curb carbon emissions. That’s a lot. We are talking about potentially losing half a million species to extinction due to climate change.
“With every increment of temperature increase there’s this acceleration of extinction risk,” Urban, director of the University of Connecticut’s Center for Biological Hazards, told Vox.
To be clear, Urban is reporting the risk of extinction. This is different from certainty of extinction. He likens an endangered species to a water jug with a crack in it: “We know the water is pouring out,” he said. “What we don’t know is how big the crack is. So we don’t know how long it will take [for the water to run out]” meaning, species to become extinct.
The study also has some important limitations. Such models are only as good as the data they contain, said researcher Crystal Mantica-Pringle of the Wildlife Conservation Society of Canada, who was not part of the study. And the research is biased toward certain types of animals and regions that are easier (and cheaper) to study, such as the forests of the United States or Europe and not the Arctic. Yet the study is accurate, according to Mantika-Pringle and Ilia Maclean, a conservation ecologist at the University of Exeter, who was also not associated with the study. “It’s a pulse check of where we are,” Mantika-Pringle told Vox.
Frogs and animals on mountains and islands are most at risk
The paper also explored which animals and habitats are most and least vulnerable to warming. For example, birds facing less risk of extinction are found in urban areas, perhaps because they can move around more easily. As the ideal habitat for avian species shifts towards the poles or mountains, birds will try to migrate with it. That said, warming still poses a serious problem for many avian species, and Other studies Suggests birds face high extinction risk in North America.
Conversely, organisms that cannot move easily, such as plants or those that are highly dependent on water, will be more at risk, Urban says. In fact, Urban’s analysis found that amphibians, including frogs, are the most sensitive to warming. Climate change may intensify droughts and frogs need water. Warmer temperatures may also contribute to increased numbers of the chytrid fungus, a deadly pathogen that has wiped out dozens of frog species. What’s more, amphibians usually don’t travel very far, so it’s difficult for them to change their habitat.
According to the analysis, different habitats, mountains, islands and freshwater ecosystems appear to be most sensitive to climate change. Again, this is not shocking. Mountain-dwelling animals may move to higher elevations as temperatures warm, but they will eventually reach the top and literally run out of room. that lead some scientists To describe climate change as an “escalator towards extinction” for mountain species.
Islands face similar spatial problems and tend to be home to species with small populations to begin with. Plus, they’re already battling other threats, like invasive species, that could make warming worse. This point is important: climate change is only one threat, but it often exacerbates others, such as droughts associated with deforestation or the spread of wildlife diseases.
Are these numbers really bad?
Except for the worst-case scenario for greenhouse emissions, the study projects that a relatively small fraction of species will become extinct due to climate change—a single-digit percentage. Is that really a problem?
yes
yes
yes
This is the widely held answer, at least from ecologists. Even a small percentage translates into thousands of species, each of which has value to human society, whether we realize it or not.
A single animal species may be important to the culture of a community, eg Chinook salmonwhich is considered sacred by some indigenous tribes of the American West. And we already know that the natural world has cures for many deadly diseases. The researchers’ guess is a surprise 70 percent Currently used antibiotics and cancer treatments are rooted in natural organisms.
“Most people love nature, and that’s one aspect of it, but biodiversity is the foundation of our health and our wealth and our culture,” Urban said.
Even letting a species go extinct is like playing Russian roulette, he said.
“We don’t know what we’re missing,” Urban said. “But when you really lose a species, it’s really irreversible. That’s the end.”
