Is global warming a threat to land and marine ecosystems?

January 23, 2014

Yes, global warming is impacting species and habitats across America and around the world. According to the U.S.'s National Fish, Wildlife, and Plants Climate Adaptation Strategy, warmer temperatures, rising sea levels, and other climate-related changes are stressing countless species of plants, animals, and fish. Adaptable species with wide geographic ranges—such as white-tailed deer and feral hogs—are likely to continue to thrive. But those species that depend on particular habitats—such as the southwestern willow flycatcher (bird) and coldwater fishes—are vulnerable.

Here are some specific examples (selected from among many that are available):

  • Warmer temperatures and droughts are expected to put some of the 750 million acres of forests in the United States under greater stress, cause decreased productivity, and increase risk of fire.
  • Millions of acres of lodgepole pine and other conifer trees across the West have been killed by an epidemic outbreak of mountain pine beetles. Warmer temperatures have enabled more beetles to survive the winter and earlier arrivals of spring have allowed the insect to reproduce more generations per year while expanding their range.
  • Roughly 285 million acres of grasslands in the U.S. stretch from Canada to the Gulf Coast, and include tallgrass prairie, cattle pastures, and prairie pothole wetlands that serve as breeding grounds for ducks. Warmer, drier conditions expected from climate change will likely dry up wetlands, speed the invasion of non-native grasses and pests, contribute to more fires, and reduce the quality of forage for livestock and wildlife.
  • Many of the nation's lakes, rivers, and streams are expected to warm. Coldwater fish like trout and salmon will be adversely affected, while warmer water species like bass will expand their range. Falling water levels, especially in the Great Lakes, will lead to shoreline habitat loss, affecting nursery grounds and nesting areas.
  • Many commercial and recreational fish stocks along the East Coast have shifted their distributions northward from 25 to 200 miles over the past 40 years as ocean temperatures have increased.
  • As the ocean absorbs much of the additional carbon dioxide humans put into the atmosphere, its waters grow more acidic. In 2007–08, two major West Coast oyster hatcheries found that their oyster larvae were dying due to the higher acidity of the seawater being pumped into their facilities.
  • Small increases in ocean temperature severely stress corals and cause them to expel the symbiotic algae that nourish them and give them their vibrant colors. This process, known as "coral bleaching," changes their color to a dull white and leaves this vibrant ecosystem dead or dying.

Photo of coral bleaching in American Samoa.

Before and after images of the bleaching in American Samoa. The first image was taken in December 2014. The second image was taken in February 2015 when the XL Catlin Seaview Survey responded to NOAA’s coral bleaching alert. Credit: XL Catlin Seaview Survey.


National Fish, Wildlife, and Plants Climate Adaptation Partnership (2012): National Fish, Wildlife, and Plants Climate Adaptation Strategy. Association of Fish and Wildlife Agencies, Council on Environmental Quality, Great Lakes Indian Fish and Wildlife Commission, National Oceanic and Atmospheric Administration, and U.S. Fish and Wildlife Service. Washington, D.C. DOI: 10.3996/082012-FWSReport-1