Posts tagged Global Warming
![The figure above is a [very] simple model displaying isostatic rebound of Greenland if its ice sheet were not present. The Greenland ice sheet (GISh) is 2,500 km north-south, 1,000 km east-west, 3 km thick, and covers almost 2 million square kilometers (or 80% of the island). Because of the weight of GISh, the continental lithosphere is depressed in an elastic motion. If the GISh were to be removed, the lithosphere would rise in reaction. This rebounding process is known as isostasy and in case of ice sheets, glacial rebound.
Underneath any vast ice sheet is a land surface not unlike any other ice-free surface on earth. It has valleys, hills, plains, etc. Therefore, we see that in Greenland the underlying topography, the Bedrock (or simply the Bed), is shaped as a concave, and with the removal of the ice sheet it rises and assumes a less curved form.
PS: Please note that this is purely for visualization purposes and not to be used in scientific analysis.](http://27.media.tumblr.com/tumblr_ltdut3Ejs91qff4ofo1_400.jpg)
The figure above is a [very] simple model displaying isostatic rebound of Greenland if its ice sheet were not present. The Greenland ice sheet (GISh) is 2,500 km north-south, 1,000 km east-west, 3 km thick, and covers almost 2 million square kilometers (or 80% of the island). Because of the weight of GISh, the continental lithosphere is depressed in an elastic motion. If the GISh were to be removed, the lithosphere would rise in reaction. This rebounding process is known as isostasy and in case of ice sheets, glacial rebound.
Underneath any vast ice sheet is a land surface not unlike any other ice-free surface on earth. It has valleys, hills, plains, etc. Therefore, we see that in Greenland the underlying topography, the Bedrock (or simply the Bed), is shaped as a concave, and with the removal of the ice sheet it rises and assumes a less curved form.
PS: Please note that this is purely for visualization purposes and not to be used in scientific analysis.
A simple exercise: compare these two New York City maps. One is a map of areas that will be impacts by a rise in sea level resulting from climate change and the other is a map of Hurricane Irene evacuation zones. They show that both a hurricane and climate change can have similar impacts on humans living in low-lying areas. The only difference is that one is a devastating weather event with rapid impacts, while the other is a gradual process that’s not immediately noticeable (and thus easily deniable).
So, if you live in low-lying areas, then you better get used to evacuating. Seven billion human beings and everything associated with them does impact the natural environment, to say otherwise is a rejection of common sense.
Permafrost is ground that is at or below the freezing point of water (0 °C or 32 °F) for two or more years. Ice is not always present, as may be in the case of nonporous bedrock, but it frequently occurs. Most permafrost is located in high latitudes (i.e. land close to the North and South poles), but alpine permafrost may exist at high altitudes in much lower latitudes. Permafrost exists in 24% of exposed land in the Northern Hemisphere.
A First Visit to North Greenland - Part I
After a five-hour flight from Baltimore Washington International Airport, I landed at the Thule Air Base in northwestern Greenland as part of Columbia University’s team in NASA’s Operation IceBridge (OIB). The program is a six-year campaign of annual flights to each of Earth’s polar regions that began in the Fall of 2009. The flights in March and April carry researchers over Greenland and the Arctic Ocean while the ones in October and November take them over the Earth’s southern ice-covered regions. Both sets of flights study changes to the Earth’s sea ice, ice sheets, and glaciers. Data collected will help scientists bridge the gap between NASA’s Ice, Cloud and Land Elevation Satellite (ICESat-I), which retired in February 2010; and ICESat-II, scheduled to launch in 2014.
Thule Air Base is the United States Air Force’s northernmost base and is located some 1,100 kilometers north of the Arctic Circle, and 1,500 kilometers south of the North Pole on the northwest side of Greenland. It is approximately 900 km east of the North Magnetic Pole.
Greenland is called “Kalaallit Nanaat” in the local Inuit language. It is a country in the Kingdom of Denmark and is the largest island in the world. “Thule” is from the Latin word with the same spelling meaning ― northernmost part of the habitable world. More than 80 percent is covered either by the ice cap or smaller glaciers. According to scientific measurements, the greatest thickness of the ice cap above sea level is about 3 kilometers. If the entire 2,850,000 cu.km of ice were to melt, it would lead to a global sea level rise of 7.2m.
The US Air Base at Thule was (still is?) of strategic importance during the Cold War. It is part of the USAF Ballistic Missile Early Warning System (BMEWS) and houses the first operational ballistic missile detection radar. It was built at the height of the Cold War and provides a long-range warning of a ballistic missile attack over the polar region of the Northern Hemisphere.
In 1968, a USAF B-52 Bomber armed with four hydrogen bombs, crashed near the air base causing the nuclear payload to rupture and disperse, which resulted in widespread radioactive contamination.Three of the four nuclear warheads were recovered. The fourth is buried somewhere beneath the ice and snow around Thule.
Thule from above
Continued… Part II
