Temporary Closure of Waters Around Alcatraz Island
From 7/3 to 9/22 a 500’ marine buffer zone is in effect, closing the perimeter of Alcatraz Island to all private vessels to protect nesting seabirds during America's Cup racing. Tours to Alcatraz continue as usual during the races. More »
Muir Beach (but not nearby Muir Woods) closed July 8-November 2013, but local businesses are open
Though Muir Beach is closed from July 8-November 2013 due to construction, the PELICAN INN IS OPEN. Restrooms and parking are not available at Muir Beach. Pacific Way is closed except to residents. Check back for updates or call (415)561-3054. More »
CAUTION: Post Storm Damage to Coastal Trail
The Presidio Coastal Trail segment just north of the Pacific Overlook and adjacent to Lincoln Blvd remains CLOSED indefinitely. We have posted signage to alert bicyclists and hikers and with information for safe trail alternatives. More »
What is Climate Change?
The terms global warming and climate change are often used interchangeably, but the two phenomena are different.
Global warming is the rise in global mean temperature due to an increase of heat-trapping greenhouse gases such as carbon dioxide and methane in the atmosphere (see figure below). Based on surface and atmospheric temperatures from thousands of locations, and from satellites worldwide, scientists have determined that the global mean temperature has risen 0.8 degrees C, since 1880.
Climate change is a more general term that refers to changes in many climatic factors (such as temperature and precipitation) from the global to the local scale. These changes are happening in response to global warming and other factors at different rates and in different ways. For example on a large scale, the United States has become wetter over the 20th century, while the Sahel region of central Africa has become drier. In California, global warming and associated climate change is decreasing the Sierra snow pack and melting it sooner, causing water shortages across the state. Locally, the timing and amount of rainfall may change, potentially resulting in more frequent or heavier storms. This could lead to increased hillside erosion and flooding.
Learn more about the causes and effects of global warming and climate change at these web sites.
Did You Know?
Some granite on the beaches of San Francisco arrived here from China as ballast in ships during the Gold Rush.