Source: USFWS

A growing body of evidence has linked accelerating climate change with observed changes in fish and wildlife, their populations, and their habitats in the United States. Polar bear population declines have already been noted in Canada, and extirpations of Bay Checkerspot Butterfly populations in the San Francisco Bay area are also documented. Across the continental United States, climate change is affecting the migration cycles and body condition of migratory songbirds, causing decoupling of the arrival dates of birds on their breeding grounds and the availability of the food they need for successful reproduction. 

Climate change has very likely increased the size and number of wildfires, insect outbreaks, pathogens, disease outbreaks and tree mortality in the interior West, the Southwest and Alaska. In the aquatic environment, evidence is growing that higher water temperatures resulting from climate change are negatively impacting cold- and cool-water fish populations across the country. Along our coasts, rising sea levels have begun to affect fish and wildlife habitats, including those used by shorebirds and sea turtles that nest on our coastal National Wildlife Refuges. In the oceans, subtropical and tropical corals in shallow waters have already suffered major bleaching events driven by increases in sea surface temperatures. 

Climate change has the potential to cause abrupt ecosystem changes and increased species extinctions.