From Mother Nature Network's Katherine Butler:

Nearly the entire ice cover of Greenland melted in a span of four days this month, more than at any time in more than 30 years of satellite observations, according to NASA and university scientists. Researchers have not determined whether it will affect the overall volume of ice loss this summer and contribute to sea level rise.

In addition to loss of mass from the Greenland and Antarctic ice sheets, NASA notes two other factors that contribute to global sea level rise: Thermal expansion of seawater due to global warming and widespread melting of land ice. As the old ice of Earth melts, photographers have captured its decline.

NASA notes that for the past 650,000 years, there have been seven cycles of natural glacial advance and retreat — the last ending 7,000 years ago. These happened, experts believe, because of slight variances in the Earth’s orbit determining how much sun the planet receives. What is significant about our current warming trend is that NASA believes it to “very likely [be] human-induced.” Using its vast resources of technology, NASA has deduced that temperatures are rising at a rate that is unprecedented in the last 1,300 years. The Earth has been warming since 1880, and most of this has happened since the 1970s. Ice sheets, most notably in Greenland and Antarctica, have decreased in mass. While NASA continues to study the effects of climate change on Earth, it is virtually certain that ice will continue to melt, and sea levels will continue to rise.

Here are eight stunning before-and-after images detailing ice melts across our planet.

List, captions, and photos courtesy of Mother Nature Network

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  • Ice Melt In Alaska

    Pictured here is Muir Glacier, Alaska. On the left, 1891. On the right, 2005. Located in the East Arm of Glacier Bay, Muir Glacier, once enormous, is now called Muir Inlet. It was named for famous naturalist John Muir, who visited the glacier in the 19th century. It has been in decline for at least a century. As Fremont Morse, a government surveyor, wrote in 1905, "the sight and sound of one of these vast masses falling from the cliff, or suddenly appearing from the submarine ice-foot, was something which once witnessed, <a href="http://www.isset.org/site_of_the_month/glacier_bay/glacierbay.script.html" target="_hplink">was not to be forgotten</a>." In 2011, the international Arctic Monitoring and Assessment Program reported that, since 2005, surface temperatures in the Arctic have been higher than for <a href="http://www.adn.com/2011/06/16/1921104/arctic-ice-melting-faster-than.html" target="_hplink">any five-year period since record keeping began in 1880</a>.

  • Ice Melt In Italy And Switzerland

    Pictured here, we see the Matterhorn, a 15,000-foot-high mountain in the Alps between Italy and Switzerland. On the left, Aug. 16, 1960, at 9:00 a.m. On the right, Aug. 18, 2005, at 9:10 a.m. Climate change is a serious problem affecting our planet on a tremendous scale. NASA offers some quick statistics on the state of climate change. Foremost, <a href="http://climate.nasa.gov/" target="_hplink">the first decade of the 21st century was the warmest on record</a>. In 2007, Arctic summer sea ice reached its lowest extent on record. Finally, carbon dioxide concentrations are at their highest levels in 650,000 years.

  • Ice Melt In Chile

    Pictured here is a view of Patagonia, Chile, from space. On the left, Sept. 18, 1986. On the right, Aug. 5, 2002. "The 2002 image shows a retreat of nearly 10 kilometers (6.2 miles) of the glacier on the left side," writes NASA. "The smaller glacier on the right has receded more than 2 kilometers (1.2 miles)." Greenpeace visited two glaciers in Patagonia, reporting that the glaciers lost 42 cubic kilometers of ice every year for the last seven years, the equivalent of the <a href="http://www.greenpeace.org/usa/en/campaigns/global-warming-and-energy/science/impacts/global-melting/glaciers/" target="_hplink">volume of 10,000 football stadiums</a>. In 2008, <a href="http://articles.cnn.com/2008-12-16/tech/melting.ice_1_jay-zwally-ice-sheets-glaciers?_s=PM:TECH" target="_hplink">NASA reported that 1.5 trillion to 2 trillion tons</a> of ice in Alaska, Greenland and Antarctica had melted since 2003. Further, the rate of melt is accelerating.

  • Ice Melt In Tanzania

    Pictured here is Kilimanjaro Glacier, top view and side view, photographed by NASA's Landsat satellite. On the left is Feb. 17, 1993, and on the right is Feb. 21, 2000. A recent study points out that the <a href="http://e360.yale.edu/digest/glacial-ice-on-kilimanjaro-melting-at-increased-rate-study-says/2130/" target="_hplink">glaciers of Mount Kilimanjaro have shrunk 26 percent</a> since 2000 and around 85 percent since 1912. Lead author Lonnie G. Thompson, an Ohio State University glaciologist, determined through studying aerial photos and examining ice cores that this level of <a href="http://e360.yale.edu/digest/glacial-ice-on-kilimanjaro-melting-at-increased-rate-study-says/2130/" target="_hplink">melting had not happened in the area for 11,700 years</a>. While not all experts agree that Kilimanjaro's ice melt is due to global warming, Thompson counters that its trends are mirroring other melts across the globe.

  • Ice Melt In Switzerland

    Pictured here is Doldenhorn mountain, North East Ridge, Switzerland. On the left, July 24, 1960, 10:40 a.m. On the right, July 27, 2007, 10:44 a.m. The glaciers of the Swiss Alps have been in retreat in recent years, and experts are concerned that they will eventually disappear. Some scientists continue to <a href="http://www.mnn.com/earth-matters/politics/stories/science-under-fire-from-merchants-of-doubt" target="_hplink">debate the existence of global warming</a>. Meanwhile, however, a University of Colorado study found that melting ice raised sea levels worldwide by <a href="http://www.livescience.com/18372-ice-caps-glaciers-melt-satellite.html" target="_hplink">an average of .06 inches each year from 2003 through 2010</a>. Further, the meltoff from all the world's glaciers, ice sheets and caps in the past eight years could <a href="http://www.livescience.com/18372-ice-caps-glaciers-melt-satellite.html" target="_hplink">cover the United States in about 18 inches of water</a>, according to new research reported in Live Science.

  • Ice Melt In Himalayas

    Pictured here is the Imja Glacier in the Himalayas. On the left is 1956. On the right is 2007. "The latter image shows pronounced retreat and collapse of the lower tongue of the glacier and the formation of new melt ponds," NASA writes. However, a recent study shows that the glaciers of the Himalayas are melting more slowly than previously thought. A team from the University of Colorado, Boulder, used satellite data to determine that the majority of the <a href="http://www.csmonitor.com/Science/2012/0209/Study-Himalayan-glaciers-melting-more-slowly-than-thought-but-seas-are-still-rising" target="_hplink">ice loss causing sea levels to rise</a> was mostly coming from Greenland and Antarctica, reports the Christian Science Monitor. While this is positive news for the Himalayas, it is still disturbing for threatened coastlines around the globe.

  • Ice Melt In Greenland

    Here we see the Petermann Glacier in Greenland. These satellite images show <a href="http://climate.nasa.gov/sof/?CFID=3338713&CFTOKEN=17324256#Icemelt_Greenland3.jpg" target="_hplink">a large iceberg has broken off the Petermann Glacier</a>, which is the "curved, nearly vertical stripe stretching up from the bottom right of the images," NASA notes. "Even if you don't have record-breaking highs, as long as warm temperatures persist, you can get <a href="http://www.sciencedaily.com/releases/2011/10/111025163128.htm" target="_hplink">record-breaking melting because of positive feedback mechanisms</a>," according to Dr. Marco Tedesco, a scientist at the Cryospheric Processes Laboratory at The City College of New York who recently conducted a study on ice melt in Greenland and was reported in Science Daily. In other words, when temperatures remain relatively warm, glaciers are "amplifying" their own cycle of melting.

  • Ice Melt In Peru

    Pictured here is the Qori Kalis Glacier, Peru. On the left, July 1978. On the right, July 2004. Peru is home to the Andes, which contains the world's largest tropical body of ice. The British Climate Change Vulnerability Index reports that Peru has been extremely affected by warming global temperatures, having lost at least <a href="http://www.dw.de/dw/article/0,,14858234,00.html" target="_hplink">22 percent of its ice mass since 1970</a>. And as time passes, ice melt is accelerating.

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