Perhaps the most visible sign that Earth's climate is warming is the gradual shrinking of its glaciers. In North America, the most visited glacier is the Athabasca Glacier, one of six glaciers that spill down the Canadian Rockies from the Columbia Icefield in western Canada. Visitors who return to the glacier a few years after their first visit will notice the change wrought by warming temperatures. In the past 125 years, the Athabasca Glacier has lost half of its volume and receded more than 1.5 kilometers (0.93 miles), leaving hills of rock in its place. Its retreat is visible in this photo, where the glacier's front edge looms several meters behind the tombstone-like marker that indicates the edge of the ice in 1992. The Athabasca Glacier is not alone in its retreat: Since 1960, glaciers around the world have lost an estimated 8,000 cubic kilometers (1,900 cubic miles) of ice. That is approximately enough ice to cover a two-kilometer-wide (1.2 mile-wide) swath of land between New York and Los Angeles with an ice sheet that is one kilometer (0.62 miles) tall. Melting glaciers, dwindling sea ice, rising global temperatures, and rising sea levels. Little by little the evidence is adding up to show that Earth is getting hotter, and scientists are almost certain that people are to blame. A number of activities from burning fossil fuels to farming pump heat-trapping gases--greenhouse gases--into the atmosphere. Once in the atmosphere, these gases stay there for thousands of years, absorbing the heat that comes from the Earth and re-radiating it back to the surface, enhancing Earth's natural greenhouse effect. Between 1906 and 2006, the average surface temperature of the Earth rose 0.6 to 0.9 degrees Celsius (1.08 to 1.62 degrees Fahrenheit), while greenhouse gas concentrations reached their highest levels in at least the past 650,000 years. Most climate scientists believe that there is a connection and warn that if greenhouse gas emissions continue, temperatures are likely to go up 2 to 6 degrees Celsius (3.6 to 10.8 degrees F) by the end of the 21st century. While this might seem like a small change, it will probably lead to big changes in the environment. Warming temperatures will likely lead to more frequent heat waves, bigger storms, including more intense tropical cyclones (hurricanes), and more widespread drought. Since water expands as it heats, and melting glaciers and ice caps have dumped more fresh water into the world's oceans, sea levels have already started to rise. Higher sea levels lead to more erosion and greater storm damage in coastal areas, many of which are densely populated. As much as 10 percent of the world's population lives in vulnerable coastal regions that have an elevation less than 10 meters (32 feet) above sea level. To understand what global warming means for humanity, it is necessary to understand what global warming is, how scientists know it's happening, and how they predict future climate. These ideas are explored
description
Perhaps the most visible sign that Earth's climate is warming is the gradual shrinking of its glaciers. In North America, the most visited glacier is the Athabasca Glacier, one of six glaciers that spill down the Canadian Rockies from the Columbia Icefield in western Canada. Visitors who return to the glacier a few years after their first visit will notice the change wrought by warming temperatures. In the past 125 years, the Athabasca Glacier has lost half of its volume and receded more than 1.5 kilometers (0.93 miles), leaving hills of rock in its place. Its retreat is visible in this photo, where the glacier's front edge looms several meters behind the tombstone-like marker that indicates the edge of the ice in 1992. The Athabasca Glacier is not alone in its retreat: Since 1960, glaciers around the world have lost an estimated 8,000 cubic kilometers (1,900 cubic miles) of ice. That is approximately enough ice to cover a two-kilometer-wide (1.2 mile-wide) swath of land between New York and Los Angeles with an ice sheet that is one kilometer (0.62 miles) tall. Melting glaciers, dwindling sea ice, rising global temperatures, and rising sea levels. Little by little the evidence is adding up to show that Earth is getting hotter, and scientists are almost certain that people are to blame. A number of activities from burning fossil fuels to farming pump heat-trapping gases--greenhouse gases--into the atmosphere. Once in the atmosphere, these gases stay there for thousands of years, absorbing the heat that comes from the Earth and re-radiating it back to the surface, enhancing Earth's natural greenhouse effect. Between 1906 and 2006, the average surface temperature of the Earth rose 0.6 to 0.9 degrees Celsius (1.08 to 1.62 degrees Fahrenheit), while greenhouse gas concentrations reached their highest levels in at least the past 650,000 years. Most climate scientists believe that there is a connection and warn that if greenhouse gas emissions continue, temperatures are likely to go up 2 to 6 degrees Celsius (3.6 to 10.8 degrees F) by the end of the 21st century. While this might seem like a small change, it will probably lead to big changes in the environment. Warming temperatures will likely lead to more frequent heat waves, bigger storms, including more intense tropical cyclones (hurricanes), and more widespread drought. Since water expands as it heats, and melting glaciers and ice caps have dumped more fresh water into the world's oceans, sea levels have already started to rise. Higher sea levels lead to more erosion and greater storm damage in coastal areas, many of which are densely populated. As much as 10 percent of the world's population lives in vulnerable coastal regions that have an elevation less than 10 meters (32 feet) above sea level. To understand what global warming means for humanity, it is necessary to understand what global warming is, how scientists know it's happening, and how they predict future climate. These ideas are explored
description
description:
in the Earth Observatory's newly updated fact sheet on global warming. We invite you to read http://earthobserva…Global Warming . * Dyurgerov, M., and Meier, M. (2005). Glaciers and the Changing Earth System: A 2004 snapshot (Occasional Paper 58). Boulder, CO: Institute of Arctic and Alpine Research, University of Colorado. * www.pc.gc.ca/pn-np/a b/jasper/visit/visit 32_e.asp Jasper National Park of Canada, Parks Canada. Accessed May 14, 2007. * Intergovernmental Panel on Climate Change. (2007). Climate Change 2007: The Physical Science Basis Summary for Policymakers, A Report of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change.
description
in the Earth Observatory's newly updated fact sheet on global warming. We invite you to read http://earthobserva…Global Warming . * Dyurgerov, M., and Meier, M. (2005). Glaciers and the Changing Earth System: A 2004 snapshot (Occasional Paper 58). Boulder, CO: Institute of Arctic and Alpine Research, University of Colorado. * www.pc.gc.ca/pn-np/a b/jasper/visit/visit 32_e.asp Jasper National Park of Canada, Parks Canada. Accessed May 14, 2007. * Intergovernmental Panel on Climate Change. (2007). Climate Change 2007: The Physical Science Basis Summary for Policymakers, A Report of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change.
description
subject:
What -- Earth
subject
What -- Earth
subject
subject:
What -- Columbia
subject
What -- Columbia
subject
subject:
Where -- Los Angeles
subject
Where -- Los Angeles
subject
subject:
Where -- New York
subject
Where -- New York
subject
subject:
Where -- Canada
subject
Where -- Canada
subject
subject:
What -- Snapshot
subject
What -- Snapshot
subject
what:
Earth
what
Earth
what
what:
Columbia
what
Columbia
what
what:
Snapshot
what
Snapshot
what
where:
Los Angeles
where
Los Angeles
where
where:
New York
where
New York
where
where:
Canada
where
Canada
where
identifier:
glacier_loss_athabas ca
identifier
glacier_loss_athabas ca
identifier
uploader:
gwilliam@archive.org
uploader
gwilliam@archive.org
uploader
addeddate:
2011-07-09 00:04:35
addeddate
2011-07-09 00:04:35
addeddate
publicdate:
2011-07-09 00:04:35
publicdate
2011-07-09 00:04:35
publicdate
creator:
NASA -- Photograph [Copyright]2005 www.flickr.com/photo s/hughrocks/35342787 / Hugh Saxby, glacier graph adapted from Dyurgerov and Meier, 2005.
creator
NASA -- Photograph [Copyright]2005 www.flickr.com/photo s/hughrocks/35342787 / Hugh Saxby, glacier graph adapted from Dyurgerov and Meier, 2005.
