Climate scientists recently issued a warning on global warming, prompting a UN demand for politicians to tackle the global warming crisis. Global average surface temperatures could rise by between 1.1 °C (1.98 °F) and 6.4 °C (11.52 °F) compared to 1980-99 levels. Sea levels will rise by at least 18 centimeters (7.2 inches). Heat waves, rainstorms, tropical cyclones and surges in sea level are among the events expected to become more frequent, more widespread or more intense this century.
The extent of these changes has prompted concern about the possible effects on the global physical, chemical and biological systems. Large-scale changes in land use at rates unprecedented in human history are provoking considerable concern. Land use change is frequently accompanied by alterations or changes in land cover, which may possibly contribute to subsequent environmental change. Evaluation of static attributes (types, amount and arrangement) and the dynamic attributes (types and rates of change) on satellite images may allow the types of change to be regionalized and the proximate sources of change to be identified or inferred. This information, combined with results of case studies or surveys, can provide helpful input to informed evaluations of interactions among the various driving forces.
Greenland Ice Sheets
Photo by Roger J. Braithwaite
ASTER Satellite Image
Image Credit: NASA
Video - Antarctica Cloudless Satellite Images by NASA
Ice Sheets Melting in Nares Strait between Greenland and Canada from 20th of January to 24th March 2007 — by European Space Agency
Satellite image data is expected to contribute to a wide array of global change-related application areas for vegetation and ecosystem dynamics, hazard monitoring, geology and soil analysis, land surface climatology, hydrology, land cover change, and the generation of orthorectified digital elevation models (DEMs).
The satellite images above on the right is from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) satellite and shows the Helheim glacier in June 2005 (top), July 2003 (middle), and May 2001 (bottom). The glacier occupies the left part of the images, while large and small icebergs pack the narrow fjord in the right part of the images. Bare ground appears brown or tan, while vegetation appears in shades of red.
Satellite observations of eastern Greenland's Helheim Glacier show that the position of the iceberg's calving front, or margin, has undergone rapid and dramatic change since 2001, and the glacier's flow to the sea has sped up as well.
From the 1970s until about 2001, the position of the glacier’s margin changed little. But between 2001 and 2005, the margin retreated landward about 7.5 kilometers (4.7 miles), and its speed increased from 8 to 11 kilometers per year. Between 2001 and 2003, the glacier also thinned by up to 40 meters (about 131 feet). Scientists believe the retreat of the ice margin plays a big role in the glacier’s acceleration. As the margin of the glacier retreats back toward land, the mass of grounded ice that once acted like a brake on the glacier’s speed is released, allowing the glacier to speed up. Overall, the margins of the Greenland Ice Sheet have been thinning by tens of meters over the last decade.
QuickBird Satellite Image
In addition to changes in the atmosphere's composition, changes in the land surface can have important effects on climate. For example, land change can affect temperature by changing how much solar radiation the land reflects and absorbs. Processes such as deforestation, reforestation, desertification and urbanization often contribute to changes (including temperature, wind and precipitation) in the places they occur. These effects may be significant regionally, but reduced when averaged over the entire globe.
From space, the whole world unfolds every day. Orbiting the planet, Earth Observing satellite sensors are uniquely able to make the kinds of measurements that experts need to track systemic changes on the Earth below.
Image Credit: NOAA
With regard to studies about the Earth's cryosphere, high resolution satellite sensors such as the GeoEye-1 at 0.41m resolution, WorldView-2 at 0.46m, Worldview-1, QuickBird, and IKONOS, these sensors will be an important tool for tracking changes in the Arctic and elsewhere.
Changes in land cover and land use can also affect the amount of carbon dioxide taken up (or sequestered) or released by the land surface. For more information, visit EPA's Carbon Sequestration in Agriculture and Forestry site.
For more information on the state of knowledge of land use change on climate, see the Climate Change Science Program's Strategic Plan's Chapter on Land Use/Land Cover Change.