The first mammal species declared extinct as a result of climate change was officially pronounced extinct in 2019.
The last known Bramble Cay melomys, a small Australian rodent, died as a result of what scientists believe were storm surges that either killed the population or devastated the vegetation they needed to survive on Torres Strait, in northern Queensland near Papua New Guinea.
Nearby, more coral reefs were damaged and bleached by warming seas while growing acidity made it harder for mussels, clams, urchins, and other creatures to build strong shells. Elsewhere in the oceans, marine mammals are threatened by diseases spread between formerly isolated populations that now can reach each other because of melting ice.
In North America, the wood thrush was in danger of losing more than half its range, and the Audubon Society also says that changing climate is threatening two-thirds of bird species, including the piping plover, tricolored blackbird, and bobolink. Other researchers find good reason to fear that the Cascade frog of the Pacific Northwest could be extinct by 2080. The news is just as bleak on other continents of the globe.
In total, 1 million of an estimated 8 million animal and plant species worldwide are threatened with extinction as a result of habitat loss, exploitation of nature, climate change, pollution, and invasive alien species, according to the 2019 Global Assessment by the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES).* The report says many of these species may become extinct within decades, and it notes the “current rate of global species extinction is [tens to hundreds of times] higher compared to average over the last 10 million years, and the rate is accelerating.”
“Nature is declining globally at rates unprecedented in human history,” says the press statement about the report, which was authored by 145 experts representing 50 nations, in addition to 310 other contributing authors. It notes a huge percentage of species are threatened, including one-third of marine mammals and 40 percent of amphibians.
While news about extinctions is sobering, many – though not all – of the world’s governments are working together to combat factors contributing to climate change. Individuals can also make climate-and-wildlife-conscious choices in their daily lives. That website offers ways to calculate one’s carbon footprint, reduce energy use, and eat with the planet in mind by learning about that “footprint.” Some experts hope these countless small actions can be one part of a far more vast global effort to save the world’s wildlife from the threats they face.
Following is a sampling of a few of the climate-related threats wildlife around the globe are facing.
Two-thirds of North American birds at risk of extinction
In October 2019, a report by the National Audubon Society pointed to climate change as imperiling two-thirds of avian species in North America, leaving them at risk of extinction. Scientists examined 140 million bird records from numerous species.
The report, entitled “Survival by Degrees: 389 Bird Species on the Brink,” noted 76 percent of these species would benefit from reducing impacts of climate change. The Audubon Society also has an interactive online tool called the “Birds and Climate Visualizer” allowing people to see how climate change will affect birds in their own zip code or state.
Global fisheries declining
The world’s oceans are facing a number of changes brought about by climate change: temperatures are rising, oxygen levels are decreasing, and the seas are becoming increasingly acidic (technically becoming less basic, but not at the point of actually being “acidic”). This combination can lead to an increase in algal growth, red tides, and other factors posing risks to fish and other species. As many people across the world rely on fish and seafood for nutrition, declining fisheries could have critical implications for global food security.
Authors of a 2019 study in Science found a 4.1 percent decline in fishery productivity between 1930 and 2010. They reported that productivity in some ecoregions declined by as much as 35% during that time period. Combined with climate-change losses in crop production, that loss of fisheries productivity could have grave implications for food security.
Compounding effects of climate change on amphibians
Frogs, toads, salamanders, and other amphibians are considered “indicator species” because they are susceptible to even subtle environmental changes.
A study published in Global Change Biology found higher temperatures, in combination with infectious disease, responsible for the decline in some amphibian species through the “thermal mismatch hypothesis.” The study reported that “Only the combination of rapid increases in temperature and infectious disease could account for the patterns of declines, especially in species adapted to relatively cool environments.” The study authors found the most vulnerable species to be those adapted to cooler temperatures.
Authors of another 2019 study, published in Ecological Applications, examined the Cascades frog, finding the frog to be adversely affected by the “compounding effects of climate change.” Researchers found that warmer temperatures and smaller snowpacks can mean the snow melts and dries out sooner, drying up crucial wetlands and threatening frog larvae. Adults are also threatened by shorter winters and less summer precipitation. The authors found the Cascade frog to have “a 62% chance of extinction by the 2080s because of compounding negative effects on early and late life history stages.”
Melting sea ice leads to spread of marine mammal disease
Melting Arctic ice is creating more pathways for deadly diseases to circulate among marine mammals. Phocine distemper virus killed thousands of animals in the North Atlantic in 2002. Just two years later, the same disease was responsible for killing otters in Alaska. Scientists concluded that melting sea ice allowed the two populations of animals – previously thought unable to reach one another – had made contact and had spread disease.
Scientists from University of California, Davis, set out on a 15-year study, publishing their findings in Scientific Reports, to learn how melting ice may allow disease transmission between populations. The researchers identified two years in which the disease was prevalent in the North Pacific – 2003 and 2009 – and when Arctic sea ice was low. The authors judge that melting sea ice may lead to more disease outbreaks spreading between North Atlantic and North Pacific populations.
Editor’s note: This story was lightly edited on March 24 to underscore IPBES’ conclusion that major causal factors are loss of biodiversity and species extinction, and not climate change. Some of the individual studies described in this survey or overview piece will be explored further in an upcoming deeper dive into the impact climate change is having on wildlife in the world’s oceans.
Tom Toro is a cartoonist and writer who has published over 200 cartoons in The New Yorker since 2010.