National Park Service the United States. In 1872, there was no state government to manage it, so the federal government assumed direct control. Yosemite National Park began as a state park; the land for the park was donated by the federal government to the state of California in 1864 for perpetual conservation. Yosemite was later returned to federal ownership. At first, each national park was managed independently, with varying degrees of success. In Yellowstone, the civilian staff was replaced by the U.S. Army in 1886. Due to the irregularities in managing these national treasures, Stephen Mather petitioned the federal government to improve the
Yosemite National Park thawing of the Ice Age (such as the Little Ice Age). Climate change has reduced the number and size of glaciers around the world. Many Yosemite glaciers, including Merced Glacier, which was discovered by John Muir in 1871 and bolstered his glacial origins theory of the Yosemite area, have disappeared and most of the others have lost up to 75% of their surface area. Yosemite has a Mediterranean climate (Köppen climate classification "Csa"), meaning most precipitation falls during the mild winter, and the other seasons are nearly dry (less than 3% of precipitation falls during the long, hot summers). Because