12 U.S. Species Endangered by Climate Change

Akikiki

Hawaii is home to a type of native honeycreeper called the Akikiki, or Kaua'i creeper, listed as critically endangered by the IUCN. Nearly all of Hawaii's endemic birds have been decimated by introduced species. It's the mosquito—accidentally introduced in the early 1800s by European colonizers—that has most damaged the Akikiki by spreading avian malaria.

The last safe haven for the birds lies in the mountains of Kauaʻi, a place too cool for mosquitoes, but these high-elevation oases are increasingly impacted by extreme weather. "Hurricanes are now thought to displace birds from the small area of suitable habitat at higher elevations and push them into the lowlands where avian malaria is prevalent," the IUCN says.

Elkhorn Coral

Elkhorn coral is among the most important reef-building coral found in the Caribbean and Florida, and the IUCN deems it critically endangered. All across Florida's reefs, the corals are steadily bleaching because of rising water temperature. As the oceans warm, they also become more acidic, hampering the ability of corals to build their protective skeletons.

A 2020 study by the National Oceanic and Atmospheric Administration assessed elkhorn coral under conditions of elevated sea temperature and increased wave height. It found that the current large population structures would greatly reduce, and that the resulting smaller colony sizes would consequently "limit the future population success" of the coral.

Bog Turtles

These tiny, charismatic reptilians are considered critically endangered by the IUCN and occur only in the Eastern U.S. Even small changes in temperature can greatly impact the bog turtle. Warmth can bring invasive species like the purple loosestrife into the turtle's habitat, which could lead to decreased water levels. Global warming is also likely to alter hydrological cycles, which will either dry out or flood what remains of the bog turtle's habitat.

Bull Trout

Less and less bull trout are frequenting the streams of Idaho, Montana, Nevada, Oregon, and Washington these days. Like many freshwater fish, the bull trout's reproduction requires cold water and very low amounts of silt, both of which are negatively impacted by road building, logging, and warming.

Bull trout are considered a management indicator species for several national forests, including Boise National Forest and Sawtooth National Forest. The IUCN, which considers them vulnerable, hasn't assessed the species since 1996. More recent assessments by the USDA have confirmed their status as threatened.

Canada Lynx

Populations of Canada lynx can be found in mountains across the U.S., from Alaska to New Mexico, Washington to Maine. These felines rely on cold, snowy winters and higher altitudes for a suitable habitat. As temperatures rise with global warming, that habitat is predicted to move up in altitude and north in latitude.

The Canada lynx is listed as a species of least concern by the IUCN, which last assessed it in 2014, but is threatened enough to be protected under the U.S. Endangered Species Act.

Pacific Salmon

As vital to the food chain as they are, salmon across the Pacific Coast are in danger. Already threatened by dams and overfishing, salmonids typically die when exposed for a length of time to fresh water temperatures above 72 degrees. Global warming has pushed the average summer temperatures of many West Coast river systems above that mortality threshold, leading now-endangered Pacific salmon further toward extinction.

Leatherback Sea Turtles

Leatherback sea turtles are considered vulnerable globally but endangered in the U.S. This remarkable species is the largest of all living sea turtles and the fourth-largest modern reptile behind three crocodilians, but its nesting sites—on the beaches of Florida, Puerto Rico, and the U.S. Virgin Islands—are universally threatened by warming sand temperatures and erosion from rising seas and storm events.

Changes in water temperature could also "alter the abundance and distribution of food resources," NOAA says, "leading to a shift in the migratory and foraging range and nesting season of leatherbacks."

Grizzly Bears

Often overshadowed by the polar bear, grizzlies are also threatened by global warming. The bears are denning later in the fall because of prolonged summer weather, which leads to more hunter-bear interaction and a decline in food sources. For example, grizzlies in Yellowstone are used to eating whitebark pine, which is being pushed out by species like Douglas firs as they're forced to retreat to higher elevations.

The IUCN lists grizzlies as a species of least concern globally, even though they're considered threatened by the U.S. Endangered Species Act.

Flatwoods Salamander

Occurring only in the Southeastern coastal plain of the U.S., the flatwoods salamander is vulnerable to habitat fragmentation and loss because of its small range. It will have nowhere to go when droughts become more frequent and intense in the South. The salamanders' eggs hatch in response to rising water levels in the ponds where they live, meaning that widespread, seasonal drought could quickly wipe out these populations.

Polar Bears

Though its status is vulnerable on the IUCN Red List, polar bears have been considered endangered in the U.S. since 2008. They were, in fact, the first mammals to be listed as threatened under the Endangered Species Act due primarily to global warming.

Polar bears' habitat is literally disappearing beneath their feet due to shrinking sea ice sheets. Global warming will affect the Arctic more than any other habitat, with temperatures likely to increase at about twice the global average.

Monarch Butterflies

Though the monarch butterfly is listed as a species of least concern by the IUCN, it's been a candidate under the Endangered Species Act since 2020. Experts believe that increased CO2 levels could be making monarch butterflies' only food source, milkweed, toxic for them to eat.

What's more, their migration routes are getting longer and longer due to rising temperatures pushing summer breeding areas further north. The butterflies have already begun growing longer wings to make up for the distance, but the climate is changing faster than they can adapt.

American Pikas

American pikas, small mammals that live in rock piles in mountainous regions of the States, are not protected under the Endangered Species Act even though the National Wildlife Federation describes their situation as "dire."

Already, they have vanished from more than a third of their alpine habitats in Oregon and Nevada due to rising temperatures. Without ESA protection, the NWF says American pikas "could be the first species to go extinct due to climate change."