NASA photos reveal Earth's changing face
A series of stunning before and after photos from NASA reveals nature's course and humanity's impact on the planet.
(Credit: NASA)
A blue marble in the depths of space
The Earth's appearance has transformed over the course of millions of years. Obviously, for much of that time, scientists weren't around to track the Earth's shifting face. But with the advent of the space age in the second half of the 20th century, it became possible to view the planet from afar, and get a sweeping perspective. Indeed, an updated NASA gallery published in conjunction with Earth Day 2012 features more than 160 comparison views demonstrating in sharp relief the very real changes that have taken place during the Earth's recent history.
(Credit: US Department of the Interior / US Geological Survey)
Fire burns in Idaho
A series of wildfires triggered by lightning strikes in August 2010 burned more than 300,000 acres across Idaho.
The top image, taken on 24 July, shows burn marks from earlier, smaller fires, while the bottom image, from August, shows the dark-brown area burned by the more recent fires.
(Credit: US Department of the Interior / US Geological Survey)
Ice melts in Chile
The 1986 image on top shows the region of Patagonia, Chile, prior to a major retreat of the glaciers. The 2002 image below shows an incredible 6.2 mile pullback of the glacier on the left side.
In front of the smaller glacier, two ribbon lakes have formed behind the debris left by the glacier's advance. Scientists are using satellite imagery like these images from the US Department of the Interior to monitor glaciers and the impact on water bodies caused by the changes in the glacier's size and direction.
(Credit: NASA/GSFC/METI/ERSDAC/JAROS and the U.S./Japan ASTER Science Team)
River changes flow in China
The Yellow River, seen here in the top image in 2001, and on the bottom in 2009, is the second-longest river in China, and the sixth-longest river in the world. It has been the cradle of Chinese civilisation, but frequent devastating floods have also earned it the name of "China's Sorrow".
Currently, the Yellow River ends in the Bohai Sea, yet its eastern terminus continues to oscillate from points north and south of the Shandong Peninsula. These images show the changes.
(Credit: US Department of the Interior / US Geological Survey)
Lakes shrink in Africa
Persistent drought has shrunk Lake Chad (seen in the image on top in 1982) from the world's sixth-largest lake to about one twentieth of the size it was in the 1960s.
As the lake has receded, large wetland areas, shown in red, have replaced open water.
(Credit: One Planet Many People Atlas of our Changing Environment; Division of Early Warning and Assessment (DEWA) UNEP)
Agriculture in Saudi Arabia
Once so barren that it could barely support the towns of Al'Isawiyah and Tubarjal, Saudi Arabia has slowly developed crop-producing fields.
Irrigation that taps an ancient aquifer containing water as much as 20,000 years old has allowed the population to sprout green fields, depicted here as green dots. Judicious use of water resources and climate-appropriate technology has improved food production without harming the environment. The top image was taken in 1986.
(Credit: US Department of the Interior / US Geological Survey)
Land recovery at Chernobyl
Twenty five years after the Chernobyl Nuclear Power Plant meltdown, the land is beginning to recover.
The image on top, taken 29 April 1986, shows bright light tones where cultivated fields were being prepared for planting, and dense, dark-green forest cover.
In the 2011 image at the bottom, limited resettlement had begun. Most of the fields are now seen in light-green grasslands, and the dense forests have been destroyed and replanted and can be seen in lighter, more uniform greens.
(Credit: US Department of the Interior / US Geological Survey)
Ice melts in Greenland
In 2010, an iceberg more than four times the size of Manhattan broke off the Petermann Glacier, probably because of warmer waters, owing to changes in global temperatures. You can see it on the right side of the bottom image.
(Credit: US Department of the Interior / US Geological Survey)
Delta restored in Louisiana
The Wax Lake Delta in Louisiana, with the Atchafalaya River seen flowing into the Gulf of Mexico, was formed by sediment following the construction of a canal through Wax Lake in 1941. Since Hurricane Katrina in 2005, the delta has served as a model for restoring wildlife habitat, and for protection against storm surge in the Mississippi River delta region.
(Credit: NASA/GSFC/METI/ERSDAC/JAROS and the U.S./Japan ASTER Science Team)
Flooding in China
Flooding has caused dramatic change in the water at Dongting Lake in Hunan Province, China. The image at the top was captured 2 September 2002, after devastating flooding.
(Credit: Data from NASA Goddard Institute for Space Studies. Courtesy of the NASA Earth Observatory and Mike Carlowicz)
Earth warms
Data maps from 1880-1889 on the top, and 2000-2009 on the bottom, illustrate global temperature changes.
These maps compare temperatures in each region of the world to what they were from 1951 to 1980. NASA's Goddard Institute for Space Studies conducted the analysis using ship-based and satellite observations of ocean temperatures, and data from Antarctic research stations and 6300 meteorological stations around the world. Earth's average surface temperature has increased by about 0.7 degrees Celsius since 1880. Two thirds of the warming has occurred since 1975, at a rate of roughly 0.15 to 0.20 degrees Celsius per decade.
(Credit: NASA/GSFC/LaRC/JPL, MISR Team)
Dust storms obscure China
Dust storms, like this one seen in 2003 in the Liaoning region of China and parts of northern and western Korea, transport mineral dust from the deserts of China and Mongolia — as well as pollution from agriculture, industry and power generation — over great distances.
(Credit: NASA's Earth Observatory)
Aral Sea shrinks in Central Asia
Central Asia's Aral Sea, once one of the largest inland bodies of salty water in the world, is shrinking.
The image on top, taken in 2000, shows the effects of water being drawn off from rivers for crop irrigation. The sea has shrunk, causing changes in the climate, dust storms and insufficient drinking water. By 2009, shown in the bottom image, the Aral Sea had lost four fifths of its water volume.
(Credit: NASA/USGS)
Deforested Bolivia
The top image was taken on 17 June 1975, and shows an area of Bolivia east of Santa Cruz de la Sierra, an area of tropical dry forest. Resettlement of people from the Andean high plains has led to deforestation in this area, as seen in the lower image, taken 25 years later on 1 August 2000.
Via CNET