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Tunnel to Marin Headlands Closed
The tunnel on Bunker Road from Alexander Avenue in Sausalito towards the Marin Headlands is closed for construction. Please follow the detour signs to Conzelman Road (just above the north end of the Golden Gate Bridge) to go up over the hill. More »
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Muir Beach (but not nearby Muir Woods) parking lot closed June-November 2013
Muir Beach parking lot will be closed from June-November 2013 due to construction. Restrooms or nearby parking will not be available at Muir Beach during this period. Pacific Way is closed except to residents. Check back for updates or call (415)561-3054 More »
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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?
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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.
Left - Naturally occurring greenhouse gases—carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O)—normally trap some of the sun’s heat, keeping the planet from freezing.
Right - Human activities, such as the burning of fossil fuels, are increasing greenhouse gas levels, leading to an enhanced greenhouse effect. The result is global warming and unprecedented rates of climate change. Will Elder, NPS
Learn more about the causes and effects of global warming and climate change at these web sites. The Intergovernmental Panel on Climate Change U.S. Climate Change Science Program Environmental Protection Agency - Climate Change Site National Aeronautics and Space Administration National Oceanographic and Atmospheric Administration
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Did You Know?
Blueschist is a form of high pressure and low temperature metamorphic rock that only forms around subduction zones.