As conditions become warmer and drier and precipitation declines, geysers in the greater Yellowstone ecosystem will likely erupt less frequently. Research by the U.S. Geological Survey found that in recent years the time between Old Faithful's eruptions increased by 15 minutes, in part because of changes in precipitation patterns. Other geysers have experienced similar trends. Extended drought could result in longer intervals between eruptions, and perhaps even cessation of activity in some geysers.
In 1850, Glacier Park had 150 glaciers. In 1968, there were 38 glaciers. Today there are 26, and they are much smaller in size than in previous years. One of the most famous in the park, Grinnell Glacier, has been reduced by nearly 90 percent over the past century. At this rate, scientists predict all the park's glaciers could be gone by 2030.
In the Yosemite Valley the mean minimum temperature has increased by nine degrees over the past century. Warming over the past several decades has reduced the amount of snow on the ground each spring and changed the timing and flow of western rivers. These changes are impacting trees, meadows, glaciers and mountain species in Yosemite National Park.
Everglades National Park lies at or close to the level of the sea and is vulnerable to sea level rise. A sea level rise of just two feet would transform up to 50 percent of the park's freshwater marsh, causing erosion and devastating ecosystems along the coastline.
Global warming will alter the flow of Appalachian streams, causing lower average flows and greater floods, both of which threaten native fish. Longer and hotter summers will increase drought and wildfires in Great Smokey National Park, increase stresses on trees, and cause plant and animal species to shift to higher latitudes or altitudes.
In Redwood forests, trees condense fog into precipitation and provide necessary water to forest species during dry summers. Recently, researchers have found that the number of foggy days along the Northern California coast has declined by 24 percent, likely due at least in part to climate change. With less fog, the entire forest ecosystem will have less water to sustain it through dry summers.