E-mails: Trump official has consulted opponents of global warming

Lava eruption, Iceland
September 6, 2014 to January 3, 2015

Since August 2014, lava has burst cracks just north of Vatnajökull, the largest glacier in Iceland. Au 6 janvier 2015, le champ de lave Holuhraun s'était étendu sur plus de 84 km 2, le rendant ainsi plus grand que l'île de Manhattan. Son épaisseur est estimée à environ 10 à 14 mètres (33 à 46 pieds). L'éruption montre des signes de ralentissement mais pourrait se poursuivre pendant des années.

Images prises par l'imageur de terrain opérationnel à bord de Landsat 8. Source: Observatoire de la Terre de la NASA

Calotte glaciaire en baisse, Islande
16 septembre 1986 au 20 septembre 2014

Plus de la moitié des nombreuses calottes glaciaires et glaciers d'Islande se trouvent à proximité ou directement au-dessus des volcans. Mýrdalsjökull, quatrième calotte glaciaire d'Islande, recouvre le volcan Katla à la pointe sud du pays. Dans l'image de 2014, les dépressions de la partie centre-sud-ouest de Mýrdalsjökull sont des chaudrons de glace causés par la chaleur géothermique provenant du sol. Le long de la partie nord de la calotte glaciaire, l'ablation a exposé des bandes de cendres brunes d'éruptions passées. Mais tous les changements ne sont pas associés à l'activité volcanique. La plupart des glaciers surveillés ont diminué depuis les années 1990, y compris le Sólheimajökull (en bas à gauche), qui a reculé jusqu’à 50 mètres (164 pieds) par an. Un parking près de ce glacier est déplacé presque chaque année pour accueillir les touristes.

Images prises par le mappeur thématique à bord de Landsat 5 et par l'imageur opérationnel de terrain à bord de Landsat 8. Source: Observatoire de la Terre de la NASA, à l'aide de données de la US Geological Survey.

Rétrécissement glacier, alaska
28 juillet 1986 au 2 juillet 2014

Le glacier Columbia, en Alaska, descend à travers les montagnes Chugach jusqu'au Prince William Sound. Lorsque les explorateurs britanniques ont étudié le glacier en 1794, son nez s'est étendu jusqu'à la limite nord de l'île Heather, près de l'embouchure de la baie Columbia. Le glacier a tenu cette position jusqu'en 1980, date à laquelle il a commencé un rapide recul. Le glacier s'est tellement aminci que le mouvement ascendant et descendant des marées affecte son écoulement jusqu'à 12 kilomètres en amont, jusqu'à ce que le lit du glacier s'élève au-dessus du niveau de la mer et que la glace perde le contact avec l'océan.

Images prises par le mappeur thématique à bord de Landsat 5 et par l'imageur opérationnel de terrain à bord de Landsat 8. Source: Observatoire de la Terre de la NASA, à l'aide de données de la US Geological Survey.

Changements dans le delta du fleuve, Chine
1er mai 1985 au 1er mai 2014

Le fleuve chinois (Huang He), en Chine, est le plus rempli de sédiments de la planète. Chaque année, il transporte des millions de tonnes de terre d'un plateau traversé à un delta construit dans la mer de Bohai. Ces images montrent la croissance du delta de 1985 à 2014. Cette dernière image montre également un autre changement: des étangs contenant des crevettes et d'autres fruits de mer (vus ici sous la forme de formes géométriques sombres le long du littoral) ont été construits sur ce qui était autrefois une marée basse.

Images prises par le mappeur thématique à bord de Landsat 5 et par l’imageur de terrain opérationnel à bord de Landsat 8. Source: Commission géologique américaine (USGS) Galerie de missions Landsat "Huang He Delta et Lauzhou Bay", Département américain de l’intérieur / USGS et NASA.

Lac en recul, Asie centrale
25 août 2000 au 19 août 2014

La mer d’Aral était le quatrième plus grand lac du monde jusqu’aux années 1960, lorsque l’Union soviétique a détourné l’eau des rivières qui alimentaient le lac afin que le coton et d’autres cultures puissent être cultivés dans les plaines arides du Kazakhstan, de l’Ouzbékistan et du Turkménistan. Le contour noir montre le littoral approximatif du lac en 1960. Au moment de l’image de 2000, le nord de la mer d’Aral s’était séparé du sud de la mer d’Aral, elle-même divisée en lobes est et ouest. Un barrage construit en 2005 a permis à la mer du Nord de récupérer une grande partie de son niveau d’eau aux dépens de la mer du Sud. Le temps sec de 2014 a provoqué l'assèchement complet du lobe oriental de la mer du Sud pour la première fois de nos jours. La perte de l’influence modératrice d’une aussi grande étendue d’eau a rendu les hivers plus froids et les étés plus chauds et plus secs. Voir aussi cette image.

Les images prises en résolution modérée imaginent un spectroradiomètre (MODIS) à bord du satellite Terra de la NASA. Source: Observatoire de la Terre de la NASA

Réduction de la pollution atmosphérique, nord-est des États-Unis
2005 à 2011

Le dioxyde d'azote (NO2) est un gaz jaune-brun pouvant causer des problèmes respiratoires, contribuer à la formation d'autres polluants et servir d'indicateur de la pollution de l'air en général. Il est produit principalement lors de la combustion d'essence dans les moteurs de véhicules et de charbon dans les centrales électriques. Grâce à la réglementation, aux améliorations technologiques et aux changements économiques, la pollution atmosphérique – y compris le NO2 – a diminué malgré l’augmentation de la population et du nombre de voitures sur les routes. Ces images représentent l’amélioration observée dans le corridor nord-est des États-Unis, de Boston à Richmond, où se sont produits certains des plus grands changements absolus de NO2.

Source: Communiqué de presse de la NASA. Source de données: satellite Aura de la NASA. Crédit image: Scientific Visualization Studio / T. De la NASA Goddard. Schindler

Sécheresse, Arizona et Utah
25 mars 1999 au 13 mai 2014

Une sécheresse prolongée, associée à des prélèvements d'eau, a provoqué une chute spectaculaire du niveau de l'eau du lac Powell. Ces images montrent la partie nord du lac, qui est en réalité un réservoir profond, étroit et sinueux qui s'étend de l'Arizona en amont au sud de l'Utah. L'image de 1999 montre des niveaux d'eau proches de leur capacité maximale. En mai 2014, le lac avait chuté à 42% de sa capacité.

Images prises par la série de satellites Landsat. Source: Observatoire de la Terre de la NASA

Sécheresse, Californie
2011, 2013 et 2014

California is undergoing its most severe drought in decades, due in part to decreased rainfall and reduced winter snowpack in the Sierra Nevada mountain range as seen in these images. In 2013, California received less precipitation than in any other year since it became a state in 1850. Water conservation efforts are already in place for many locations and the potential for wildfire and major agricultural impact is high.

Images taken by the Enhanced Thematic Mapper Plus onboard Landsat 7 and the Operational Land Imager onboard Landsat 8. Source:U.S. Geological Survey (USGS) Landsat Missions Gallery "Drought Conditions in California, USA," U.S. Department of the Interior / USGS and NASA.

Urban growth, South Korea
September 5, 1981 to September 16, 2013

The shoreline area of Incheon, South Korea, has changed dramatically over the past 32 years. Marsh areas have been turned into usable land and urban development has expanded. Islands have been connected to accommodate Incheon International Airport, which opened in 2001 and is now one of the largest and busiest in the world. The new Incheon Bridge (also called the Incheon Grand Bridge), which opened in October 2009, is visible in the 2013 image.

Images taken by the Multispectral Scanner onboard Landsat 2 and the Operational Land Imager onboard Landsat 8. Source: U.S. Geological Survey (USGS) Landsat Missions Gallery "32 Years of Change: Incheon, South Korea," U.S. Department of the Interior / USGS and NASA.

Flood, Cambodia
May 17, 2013 to October 24, 2013

In October 2013, Typhoon Nari followed heavy seasonal rains to create substantial flooding along the Mekong and Tonlé Sap Rivers in Cambodia. The flood affected more than a half million people, and more than 300,000 hectares (about three-quarters of a million acres) of rice fields are believed to have been destroyed. The capital city of Phnom Penh is just south of the image center.

Images taken by the Operational Land Imager onboard Landsat 8. Source: U.S. Geological Survey (USGS) Landsat Missions Gallery"Flooding in Cambodia," U.S. Department of the Interior / USGS and NASA.

Dam impact, Pakistan
August 2, 1999 to June 8, 2011

The Mirani Dam on the Dasht River in southern Pakistan was completed in 2006. The resulting reservoir provides water for drinking, irrigation and hydroelectric power. Though the dam also helps to control flooding, heavy rains in 2007 increased the reservoir depth from 244 to 271 feet (74 to 82 meters) with attendant flooding that displaced more than 15,000 people. The left-hand image shows the region before the dam was built. The right-hand image shows the dam in 2011 with the expanded agriculture that the dam’s water supports.

Images taken by the Enhanced Thematic Mapper Plus onboard Landsat 7 and the Thematic Mapper onboard Landsat 5. Source: U.S. Geological Survey (USGS) Landsat Missions Gallery "Mirani Dam," U.S. Department of the Interior / USGS and NASA.

Typhoon, Philippines
June 28, 2013 to November 11, 2013

Among the destruction that Typhoon Haiyan inflicted was flooding caused by massive swelling of the Agno River, the fifth largest river system in the Philippines, on the island of Luzon. More than 2 million people live in the Agno River Valley.

Images taken by the Operational Land Imager onboard Landsat 8 and the Enhanced Thematic Mapper Plus onboard Landsat 7. Source:U.S. Geological Survey (USGS) Landsat Missions Gallery "Agno River Valley flooding, Philippines (Typhoon Haiyan)," U.S. Department of the Interior / USGS and NASA.

Lake change, New Mexico
June 2, 1994 to July 8, 2013

Elephant Butte Reservoir dwindled to its lowest level in 41 years during the summer of 2013, despite monsoon rains in early July. It had been filled nearly to capacity for most of 1985 to 2000; the left-hand image from 1994 shows it about 89 percent full. At right, it has been reduced to about 3 percent. Elephant Butte is fed by the Rio Grande and is New Mexico's largest reservoir. It provides water for about 90,000 acres (364 square kilometers) of farmland and nearly half the population of El Paso, Texas. Spring runoff from mountain snowpack was well below average in spring, 2013, and anemic rains throughout the beginning of the year left 80 percent of New Mexico grappling with either "extreme" or "exceptional" drought, the two most severe categories.

Images taken by the Operational Land Imager onboard Landsat 8. Source: NASA Earth Observatory

Fire, Colorado
April 27, 2013 to June 22, 2013

The Black Forest Fire near Colorado Springs, Colorado, was the most destructive wildfire in the state's history, having burned over 14,000 acres and more than 500 homes. It was responsible for the deaths of two people and forced thousands more to leave their homes. The fire started June 11, 2013, and was considered fully contained on June 20, 2013. It began along the north side of Shoup Road, which forms the southern boundary of the burned area seen in the June 22 image. The northern portion of Colorado Springs is visible at the lower left.

Images taken by the Enhanced Thematic Mapper Plus sensor onboard Landsat 7 and the Operational Land Imager onboard Landsat 8. Source: U.S. Geological Survey (USGS) Landsat Missions Gallery "Black Forest Fire," U.S. Department of the Interior / USGS and NASA.

Lake shrinkage, Iraq
1995, 2003, and 2013

Bahr al Milh (also called Lake Razazah) is a salt sea in Iraq, fed by the Euphrates River via canal. Water levels of this shallow lake vary with the seasons, but levels have been drastically low year-round in the past decade.

Images taken by Landsat 5, the Enhanced Thematic Mapper Plus instrument onboard Landsat 7, and the Operational Land Imager onboard Landsat 8. Source: U.S. Geological Survey (USGS) Landsat Missions Gallery "Bahr al Milh," U.S. Department of the Interior / USGS and NASA.

River evolution, Louisiana
1973, 1989, and 2003

These pictures show three decades of change in the birdsfoot delta where the Mississippi River meets the Gulf of Mexico in Louisiana. The Mississippi-Missouri River system collects eroded debris from the entire central half of the United States. Upon reaching the Gulf, the river's velocity slows abruptly, reducing its ability to carry suspended mud and sand, which is then deposited in an alluvial fan pattern. The delta has changed form many times over the past 10,000 years and has varied in location along a 200-mile (322-kilometer) stretch of coastline. The birdsfoot delta has occupied its current location for only about 600 years.

1973 image taken by the Multispectral Scanner sensor onboard Landsat 1. 1989 image taken by the Thematic Mapper sensor onboard Landsat 5. 2003 image taken by the Enhanced Thematic Mapper Plus sensor onboard Landsat 7. Source: U.S. Geological Survey (USGS) Landsat Missions Gallery, “Mississippi Delta, USA,” U.S. Department of the Interior / U.S. Geological Survey.

Lake shrinkage, Argentina
July 10, 1998 to September 27, 2011

Mar Chiquita, the largest of the naturally-occurring saline lakes in Argentina, has been shrinking and getting saltier. Its water comes primarily from the Dulce River, and increasing use of the river’s water for irrigation, coupled with long periods of drought, have diminished the lake’s water level and increased its salinity. Environmental studies continue to measure the regional impact of the changes in lake size and quality.

Images taken by the Thematic Mapper sensor onboard Landsat 5. Source: U.S. Geological Survey (USGS) Landsat Missions Gallery, "Mar Chiquita change over time," U.S. Department of the Interior / USGS and NASA.

Lake growth, China
1992, 2003, and 2012

Lake Ayakkum, which is near the northern boundary of the Tibetan Plateau in central China, has been growing. This stands in contrast to many closed-basin saline lakes in Central Asia, which have been shrinking because of the construction of dams and aqueducts as well as human expansion into previously uninhabitable desert areas. Small streams fed by glaciers and snowmelt are increasing their flow to the lake. The development of a delta can be seen in the lower right portion.

Images taken by the Thematic Mapper sensor onboard Landsat 5 and the Enhanced Thematic Mapper Plus onboard Landsat 7. Source:U.S. Geological Survey (USGS) Landsat Missions Gallery, "Lake Ayakkum," U.S. Department of the Interior / USGS and NASA.

River flow, Russia
May 1, 2007 to May 17, 2007

From the time they thaw in early May, the Ob River and its tributary, the Irtysh, flow from the Altay Mountains of northern China to the Arctic Ocean. The northern reaches of the Ob flow over a flat permafrost plain past the cities of Ozernyy and Nefteyvgansk in northern Russia. Because the river cannot cut deep channels into the frozen land, it spreads out over the surrounding plain during the spring melt, as shown in the image on the right.

Images taken by the Thematic Mapper sensor onboard Landsat 5. Source: U.S. Geological Survey (USGS) Landsat Missions Gallery, "Ob River Flooding in Northern Russia," U.S. Department of the Interior / USGS and NASA.

Bear Glacier melt, Alaska
1980, 1989, 2011

This series of images shows the shrinkage of Bear Glacier from 1980 to 2011. Warming in the region has caused less buildup of snow and therefore less material for glacial growth. As the glacier has receded, ice at the end of the glacier has broken off the main body, forming icebergs in the open water. The 2011 image shows considerable retreat of the glacier's "tongue." Also see this image pair of the same glacier.

Left image taken by the Multispectral Scanner onboard Landsat 3. Center image taken by the Thematic Mapper sensor onboard Landsat 4. Right image taken by the Enhanced Thematic Mapper Plus sensor onboard Landsat 7. Source: U.S. Geological Survey (USGS) Landsat Missions Gallery, "Bear Glacier, Alaska," U.S. Department of the Interior / USGS and NASA.

Drought, Kansas
2010, 2011, 2012

The Cheyenne Bottoms Wildlife Wetlands area in central Kansas, the largest interior marsh in the United States, was dramatically impacted by the drought besetting large areas of the western U.S. in 2012. There was sufficient water in the wetland area as recently as 2010, but the levels began to diminish in 2011. By mid-July, 2012, virtually all the water had evaporated. The area has provided a resting place for millions of migrating birds every fall, and wildlife officials are using satellite images like these to help them determine what actions to take to sustain a habitat for the nesting waterfowl.

Images taken by the Thematic Mapper sensor onboard Landsat 5 and by the Enhanced Thematic Mapper Plus onboard Landsat 7. Source: U.S. Geological Survey (USGS) Landsat Missions Gallery, "Effects of Drought," U.S. Department of the Interior / USGS and NASA.

Urban growth, Philippines
January 25, 2989 to April 14, 2012

The Philippine capital of Manila is the most densely populated city in the world, with more than 1.6 million inhabitants in 14.8 square miles (38.5 square kilometers). The greater metro area covers 246 square miles (638 square kilometers) and hosts a population of over 11 million. These satellite images illustrate how much the city has expanded in little more than two decades, bringing significant infrastructure and environmental problems. The Pasig River, which cuts through the urban area, is one of the most polluted rivers in the world.

Images taken by the Thematic Mapper sensor onboard Landsat 4 and the Enhanced Thematic Mapper Plus sensor onboard Landsat 7. Source: U.S. Geological Survey (USGS) Landsat Missions Gallery, "Manila, Philippines," U.S. Department of the Interior / USGS and NASA.

Glacier calving, Greenland
July 16 and 17, 2012

The Petermann Glacier grinds and slides toward the sea along the northwestern coast of Greenland, ending in a giant floating tongue of ice. An iceberg about twice the size of Manhattan broke free of that tongue in July, 2012. Two years prior, Petermann calved an iceberg twice as big as this one. A glacier is essentially a slow-moving river of ice. When a glacier protrudes into the ocean, as the Petermann Glacier does, ice occasionally breaks off the end, creating new icebergs. The frequency depends on how fast the glacier grows because of new snow, how quickly it flows into the ocean, and how fast it melts. Petermann Glacier's floating ice tongue is the largest in the Northern Hemisphere.

Images taken by the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument onboard NASA's Aqua satellite. Source: NASA Earth Observatory

Land change, Florida
May 14, 1984 to May 25, 2011

As the U.S. population has aged, more older people have been moving from northern states to southern communities. Sumpter County in central Florida grew 75 percent since 2000, largely due to expansion of The Villages, a master-planned retirement community with a strong emphasis on golf. Started as a mobile home park in the early 1980s, The Villages was the fastest growing micro-population area in the United States by 2008. These images illustrate the changes that have accompanied this growth. Agricultural land has turned into more than 40 golf courses, and small bodies of water (shown as black) have been converted to water hazards. Lakes have been drained to provide irrigation and residential communities (very light tones) have popped up around the golf courses.

Images taken by the Thematic Mapper sensor onboard Landsat 5. Source: U.S. Geological Survey (USGS) Landsat Missions Gallery, "The Villages, Florida," U.S. Department of the Interior / USGS and NASA.

Urban growth, China
July 30, 1992 to April 8, 2012

The Binhai New Area — once home to salt farms, reed marshes and wasteland — has grown into one of China's key economic hubs. Since development began in the 1990s, it has become the home of numerous aerospace, oil, chemical and other manufacturing industries. Plans for coming years include an international airport. The changes over 20 years can be seen in these images acquired in 1992 and 2012. The Binhai New Area is located on the coast of the Bohai Sea Region southeast of China's capital city, Beijing.

1992 image taken by the Thematic Mapper sensor onboard Landsat 5. 2012 image taken by the Enhanced Thematic Mapper Plus sensor onboard Landsat 7. Source: U.S. Geological Survey (USGS) Landsat Missions Gallery, "Binhai New Area, China," U.S. Department of the Interior / USGS.

Pine Island Glacier calving, Antarctica
January 25, 2011 to January 28, 2012

Left: January 25, 2011. Right: January 28, 2012. Pine Island is one of the largest and fastest-moving glaciers in Antarctica. The Pine Island Glacier Basin contributes more ice to the sea than any other ice-drainage basin in the world, and this has increased due to recent acceleration of the ice stream caused by thinning of the glacier. Scientists are concerned about the impact Pine Island's continued thinning will have on sea level. The 2011 image shows a series of splits along the western edge of the glacier. The same area in 2012 reveals a major break that will eventually extend all the way across the glacier and calve a giant iceberg expected to cover about 350 square miles (900 square kilometers).

Images taken by the Enhanced Thematic Mapper Plus sensor onboard Landsat 7. Source: U.S. Geological Survey (USGS) Landsat Missions Gallery, "Pine Island Glacier," U.S. Department of the Interior / USGS.

Fire, Idaho
July 24, 2010 to August 25, 2010

Left: July 24, 2010. Right: August 25, 2010. A series of wildfires, triggered by lightning strikes during the weekend of August 21 and 22, 2010, burned more than 300,000 acres of sage and grasses in the south-central region of Idaho. On August 23, the fire burned over 200,000 acres in a single day. Smoke from the fires dramatically impacted air quality in a number of local communities. The July 24 image shows burn marks from earlier, smaller fires, while the August 25 image shows the dark brown tone of the large fire scar. Fire and regional vegetation-management teams used the imagery to track the fire and to plan rehabilitation of the affected areas.

Images taken by the Thematic Mapper sensor onboard Landsat 5. Source: USGS Landsat Missions Gallery, "Long Butte, Idaho Fire," U.S. Department of the Interior / U.S. Geological Survey.

Fire, Georgia, United States
April 30, 2011 to July 3, 2011

Lightning sparked wildfires near the Okefenokee National Wildlife refuge in the Honey Prairie region of Georgia, US, on April 30, 2011, after the left-hand image was taken. Dry conditions helped fuel the fires and continued lightning strikes started new ones. By July 7, over 290,000 acres had burned. The red tones of the July 3 image represent recovering vegetation in previously burned areas. Light tones are the smoke of active fires.

Images taken by the Thematic Mapper sensor aboard Landsat 5. Source: USGS Landsat Missions Gallery, "Honey Prairie Fires," U.S. Department of the Interior / U.S. Geological Survey.

Water diversion, Dead Sea
November 9, 1984 to November 28, 2011

The Dead Sea lies in the Jordan Rift Valley, bordering Jordan, Israel and the West Bank. It is one of the world's saltiest bodies of water, too salty to harbor any life other than bacteria. Minerals from the sea, however, are extracted for various industrial purposes. Mineral evaporation ponds have replaced open water in the southern part of the sea, as can be seen in the 2011 image. In recent decades, the Dead Sea has shrunk as water has been diverted from the Jordan River, the sea's main tributary. A plan has been announced to replenish the Dead Sea by building a canal from the Red Sea, providing fresh (desalinated) water to Jordan en route.

1984 image taken by the Thematic Mapper sensor onboard Landsat 5. 2011 image taken by the Enhanced Thematic Mapper Plus sensor onboard Landsat 7. Source: USGS Landsat Missions Gallery, "The Dead Sea," U.S. Department of the Interior / U.S. Geological Survey.

Lake shrinkage, Utah
August 1985 to September 2010

Dramatic change in the area of the Great Salt Lake over the past 25 years. Left: August 1985. Right: September 2010. The lake was filled to near capacity in 1985 because feeder streams were charged with snowmelt and heavy rainfall. In contrast, the 2010 image shows the lake shriveled by drought. The Promontory Peninsula (protruding into the lake from the top) is surrounded by water on three sides in the first image, but is landlocked on its eastern side in the second. Similarly, Antelope Island was encircled by water in 1985, but was connected to marshy areas in 2010. Mosaics of four satellite images were used to illustrate the changes over the full lake area.

Images taken by the Thematic Mapper sensor aboard Landsat 5. Source: USGS Landsat Missions Gallery, "Great Salt Lake—1985-2010," U.S. Department of the Interior / U.S. Geological Survey.

Coastal change, Mexico
August 7, 1993 to July 8, 2011

These images show changes to the western coastline of Sonora, Mexico due to the construction of shrimp farms over the past two decades. While the shrimp industry has generated profits and jobs, there have been concerns about its effect on the ecosystems of the region, and disputes have arisen about property rights to the communal coastal lands.

Images taken by the Thematic Mapper sensor onboard Landsat 5. Source: USGS Landsat Missions Gallery, "Aquaculture Changes Mexican Shoreline," U.S. Department of the Interior / U.S. Geological Survey.

Lake shrinkage, central Asia
1977, 1989, 2006, 2009

The Aral Sea, located in Kazakhstan and Uzbekistan in central Asia. Left: June 4, 1977. Center left: September 17, 1989. Center right: May 27, 2006. Right: June 3, 2009. Once one of the largest inland bodies of salty water in the world and the second largest sea in Asia — 70,000 square kilometers or 27,000 square miles in area — the Aral Sea has shrunk dramatically over the last 30 years. One of the main reasons is crop irrigation: water has been drawn off from the rivers that kept the Aral Sea filled. As the sea has shrunk, the local climate has become harsher, there have been contaminated dust storms, and drinking water and the local fishing industry have been lost. By the late 2000s, the Aral Sea had lost four fifths of its water volume.

Images taken by the Multispectral Scanner onboard Landsat 1, the Thematic Mapper sensor onboard Landsat 5, and the Enhanced Thematic Mapper Plus onboard Landsat 7. Source: USGS Landsat Missions Gallery, "The Vanishing Aral Sea," U.S. Department of the Interior / U.S. Geological Survey and Encyclopaedia Britannica Online.

New island appears, Red Sea
October 2007 to December 2011

A volcano erupted in the Red Sea in December 2011, apparently creating a new island. According to news reports, fishermen witnessed lava fountains reaching up to 30 meters (nearly 100 feet) high on December 19. By December 23, what looked like a new island had appeared. A thick plume can be seen in the 2011 image, dark near the bottom and light near the top, perhaps a mixture of volcanic ash and water vapor. The activity occurred along the Zubair Group, a collection of small islands off the west coast of Yemen. Running in a roughly northwest-southeast line, the islands poke above the sea surface, rising from a shield volcano. This region is part of the Red Sea Rift, where the African and Arabian tectonic plates pull apart and new ocean crust regularly forms.

Images taken by the Advanced Land Imager onboard NASA's Earth Observing-1 satellite. Source: NASA Earth Observatory.

Lake degradation, California
September 1985 to September 2010

Owens Lake lies in the Owens Valley between the Sierra Nevada and Inyo Mountains, about 130 miles north of Los Angeles, California. For thousands of years, it was one of the most important stopover sites in the western U.S. for migrating waterfowl and shore birds. However, in the early 20th century, the lower Owens River, which fed the lake, was largely diverted to the Los Angeles aqueduct. Water from springs and artesian wells kept some of the lake alive, but toxic chemicals and dust impinged on the regional environment and disturbed the bird habitat. Beginning in 1999, a plan was put in place to restore the lake region and alleviate the dust build-up, using ponds, native grasses, gravel deposits and limited shallow flooding.

Images taken by the Thematic Mapper sensor onboard Landsat 5. Source: USGS Landsat Missions Gallery, "Owens Lake restoration," U.S. Department of the Interior / U.S. Geological Survey.

Lake shrinkage, Texas

Left: June 18, 1990. Right: June 12, 2011. Lake Meredith is a reservoir formed by the Sanford Dam on the Canadian River in the Texas panhandle. Continuous drought has diminished water levels significantly in the past few years, leading to a record low in 2011. In each image, the lake is the black feature near the center. Light tones at the lower end of the lake indicate dry land and former shores. Bright green indicates healthy vegetation along the river beds and irrigated fields in the upper center of each image. The nearby industrial area (a petroleum plant and a carbon-processing plant) appears as a dark spot. The light blue tone further east is Borger, Texas.

Images taken by the Thematic Mapper sensor aboard Landsat 5. Source: USGS Landsat Missions Gallery, "Shrinking Lake Meredith, Texas," U.S. Department of the Interior / U.S. Geological Survey.

Fire, New Mexico
June 24, 2011 to July 2, 2011

Las Conchas, New Mexico. Left: June 24, 2011. Right: July 2, 2011. A major fire ripped through New Mexico, destroying sites considered sacred by American Indian tribes and threatening the Los Alamos National Nuclear Laboratory. The blaze, thought to have been started by a downed power line, burned more than 125,000 acres of the Santa Fe National Forest. In the July 2 image, burned areas are reddish brown and bright tones at the edge of the forest indicate active fires.

June image taken by the Thematic Mapper sensor aboard Landsat 5. July image taken by the Enhanced Thematic Mapper Plus sensor aboard Landsat 7. Main source: USGS Landsat Missions Gallery, U.S. Department of the Interior / U.S. Geological Survey.

Lake shrinkage, Africa
1972, 1987, 2002

Lake Chad, Africa. Left: December 8, 1972. Middle: December 14, 1987. Right: December 18, 2002. Persistent drought has shrunk Lake Chad, once the world's sixth largest lake, to about one-twentieth of the size it was in the 1960s. Only 16 to 26 feet (5 to 8 meters) deep in "normal" times, small changes in depth have resulted in large changes in area. As the lake has receded, large wetland areas (shown in red) have replaced open water.

1972 image from Landsat 1. 1987 image from Landsat 4. 2002 image from Landsat 7. Courtesy of the U.S. Department of the Interior / U.S. Geological Survey. Taken from the USGS Landsat Missions Gallery.

Water changes, Caspian Sea
1972, 1987, 2010

The Kara-Bogaz-Gol basin on the eastern edge of the Caspian Sea. Left: December 4, 1972. Middle: September 25, 1987. Right: October 10, 2010. The basin's water level has periodically undergone dramatic changes, and damming of its feeder inlets increased the magnitude of those changes. In 1980, a severe drop left a "salt bowl," with windborne salt reportedly poisoning soil and causing health problems hundreds of kilometers to the east. In 1984, the basin dried up completely. In 1992, after the barrier was breached, sea level rose, remaining fairly stable from 2000 to 2010.

1972 image taken by the Multispectral Scanner aboard Landsat 1. 1987 and 2010 images taken by the Thematic Mapper sensor aboard Landsat 5. Source: USGS Landsat Missions Gallery, U.S. Department of the Interior / U.S. Geological Survey.

Deforestation, Bolivia
1989 to 2001

Near Santa Cruz de la Sierra, Bolivia. Left: August 4, 1986. Right: August 11, 2001. Most of the tropical dry forest visible in the 1986 image (dark red) has been replaced in the 2001 image by resettlement of people from the Altiplano (the Andean high plains) and by soybean production. The radial patterns are part of the San Javier resettlement plan. At the center of each unit is a small community that includes a church, bar/cafe, school and soccer field. The rectangular, light-colored areas are fields of soybeans cultivated for export. The dark strips running through the fields are windbreaks to protect the soil, which is prone to wind erosion

1986 image taken by Landsat. 2001 image taken by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER). Reproduced from JPL's ASTER website. Courtesy of NASA/GSFC/METI/ERSDAC/JAROS, and the U.S./Japan ASTER Science Team.

River changes, China
2001 to 2009

The Yellow River Delta in China. Left: 2001. Right: 2009. The Yellow River is the second-longest river in China, and the sixth-longest in the world. It has been the cradle of Chinese civilization; but frequent devastating floods have also earned it the name of "China's Sorrow." Historical maps tell us that the river has undergone many dramatic changes in its course. 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.

Images taken by NASA's Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument. Caption adapted from the ASTER gallery. Courtesy of NASA/GSFC/METI/ERSDAC/JAROS and the U.S./Japan ASTER Science Team.

Urban growth, Saudi Arabia
1972 to 2000

The Saudi Arabian capital. Left: 1972. Middle: 1990. Right: 2000. During this time, its population soared from about half a million to more than two million. In the early 1970s, three times as many Saudi Arabians lived in rural areas as in cities. By 1990, the ratio had reversed — cities held three times as many as the rural regions.

Images taken by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument. Courtesy of NASA/GSFC/METI/ERSDAC/JAROS and the U.S./Japan ASTER Science Team.

Flood, Pakistan
2009 to 2010

Southern Pakistan. Left: August 8, 2009. Right: August 11, 2010. Twenty percent of the country is currently underwater as a result of floods caused by heavy monsoon rains that began in late July 2010. According to reports, six million Pakistanis are now homeless and around 17 million people have been affected in some way.

This false-color image pair of the affected region was acquired by the Multi-angle Imaging SpectroRadiometer (MISR) instrument onboard NASA's Terra spacecraft. The Indus River can be seen snaking across the image from lower left to upper right. In the image from 2009, the Indus is about 1 kilometer (0.6 mile) wide. In the 2010 image, the river is 23 kilometers (14 miles) wide or more in parts.

Images taken by the Multi-angle Imaging SpectroRadiometer onboard NASA's Terra spacecraft. Credit: NASA/GSFC/LaRC/JPL, MISR Team. Caption adapted from JPL's Photojournal.

Ice melt, Tanzania
February 1993 to February 2000

Mount Kilimanjaro in Africa. Left: February 17, 1993. Right: February 21, 2000. Kilimanjaro is the tallest freestanding mountain in the world and is made up of three volcanic cones. These before and after images show the dramatic decline in Kilimanjaro's icecap over recent decades.

Images taken by the NASA/USGS Landsat satellite. Credit: Jim Williams, NASA GSFC Scientific Visualization Studio, and the Landsat 7 Science Team.

Lake degradation, Tunisia
2001 to 2005

Ichkeul Lake, northern Tunisia. Left: November 14, 2001. Right: July 29, 2005; the water level is higher, but a large part of the lake appears red due to the presence of aquatic plants. Ichkeul Lake and wetlands are a major stopover point for hundreds of thousands of migrating birds who come to feed and nest. It is the last remaining lake in a chain that once extended across North Africa, and has badly deteriorated as a result of the construction of three dams on rivers supplying it and its marshes, which have cut off almost all inflow of freshwater. The Tunisian government plans to undertake various measures to retain freshwater in the lake on a year-round basis and reduce the salinity of the lake.

Images taken by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) onboard NASA's Terra satellite. Credit: NASA/GSFC/METI/ERSDAC/JAROS and the U.S./Japan ASTER Science Team. Source: the ASTER gallery.

Tsunami / Earthquake, Sumatra
May 2004 to December 2004

The city of Banda Aceh, on the island of Sumatra, before and after the 2004 Indian Ocean earthquake and resulting tsunami. Top: May 14, 2004. Bottom: December 29, 2004, days after the massive wave struck the coastline.

Images taken by the Landsat-7 satellite. Source: NASA/USGS.

Dust storm, China
March 2002 to April 2002

Dust obscuring most of the Liaoning region of China and parts of northern and western Korea.

Left: March 23, 2002, a relatively clear day. Right: April 8, 2002, a day of extremely dusty skies. Storms transport mineral dust from the deserts of China and Mongolia over great distances, as well as pollution from agriculture, industry and power generation. Asian dust has been detected as far away as Colorado. Thick clouds of dust block substantial amounts of incoming sunlight, which in turn can influence marine phytoplankton production and have a cooling effect on regional climates.

Images taken by NASA's Multi-angle Imaging Spectroradiometer (MISR). Credit: NASA/GSFC/LaRC/JPL, MISR Team.

Urban growth, Nevada
1984 to 2007

Growth in the desert. Left: 1984. Right: 2007. These images show the increasing urban sprawl of Las Vegas, Nevada, and the shrinking of Lake Mead on the border of Nevada and Arizona. Rapid growth in Las Vegas has led to increased demand for water resources, while below-average rainfall has decreased the water levels in Lake Mead, which is the source of 90 percent of southern Nevada's water.

Images taken by the Landsat-5 satellite. Credit: NASA/USGS.