Our planet is constantly changing,
and we use the vantage point of space to increase our understanding of Earth, improve lives and safeguard our future.
These images show change over
time, with periods ranging from centuries to years. Some of these effects are
related to climate change, some are not. Some document the effects of
urbanization or the ravage of natural hazards such as fires and floods. All
show our planet in a state of flux. Take a look…
Expansion in New Delhi, India
Between the times these two images were taken, the
population of India’s capital and its suburbs (known collectively as “Delhi”)
ballooned from 9.4 million to 25 million. It is now second
in population only to Tokyo, which has 38 million people.
Salt Lake Shrinkage, Utah
in the area of the Great Salt Lake over the past 25 years. 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.
Early Ice Melt, Greenland
Meltwater streams, rivers and lakes form in the
surface of the Greenland Ice Sheet every spring or early summer, but melting
began exceptionally early in 2016. Melting encourages further melting when
pods of meltwater develop, since they darken the surface and absorb more
sunlight than ice does. Surface melt contributes to sea-level rise when the
water runs off into the ocean.
Lake Urmia Changes Color
Some combination of algae and bacteria is
Iran’s Lake Urmia from green to red. The change typically occurs when
summer heat and dryness evaporate water, increasing the lake’s saltiness. Data
from satellites indicate that the lake has lost about 70% of its surface area
over the last 14 years.
Lake Degradation, California
Owens Lake lies in the Owens Valley between the
Sierra Nevada and the 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,
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.
Rafi Deforestation, Niger
Rafi Forest is the most significant area of woodland in the Maradi
Department of Niger, a west African country on the southern edge of the Sahara
Desert. These pictures show the loss of a significant fraction of the natural
landscape (darker green areas) of the forest to agriculture. Population in this
region quadrupled during the 40 years leading up to the 2007 image.
River Evolution, Mexico
These two pictures illustrate the extremes
of water flow in the Colorado River since measurements began in the late
1800s. The 1985 image was taken in the midst of record high flow, while the
2007 image shows the driest period. Excessive rains or severe droughts directly
change the amount of water available in the Colorado River Basin, and so does
the increasing pressure of human needs throughout the western states.
Glacier Melt, Greenland
Along the margin
of the Greenland Ice Sheet, outlet glaciers flow as icy rivers through
fjords and out to sea. These pictures show a fjord in which Helheim Glacier (on
the left) is crumbling into large and small icebergs (light blue, on the
right). The glacier outlet held steady from the 1970s until about 2001, then
began to retreat toward its source about 4/7 miles between 2001 and 2005. The
glacier’s flow to the sea has also sped up.
Lake Poopó, Bolivia
Lake Poopó, Bolivia’s second-largest lake and an
important fishing resource for local communities, has dried
up once again because of a drought and diversion of water sources for
mining and agriculture. The last time it dried was in 1994, after which it took
several years for water to return and even longer for ecosystems to recover.
on the Ganges River, India
rains have caused catastrophic flooding along the Ganges and other rivers
in eastern and central India. At least 300 people died and more than six million
were affected by the flooding, according to news reports. These images show a
stretch of the Ganges near Patna.
All of this knowledge about our home planet enables
policy makers, government agencies and other stakeholders to make informed
decisions on critical issues that occur all around the world. From rising sea
levels to the changing availability of freshwater, we enable studies that
unravel the complexities of our planet from the highest reaches of Earth’s atmosphere
to its core.
Surprise! Humans are turning the earth into a garbage fire a lot quicker than previously thought.
According to Australian National University researchers,
humans are speeding up climate change 170 times faster than natural
“Human-caused greenhouse gas emissions over the past 45
years have increased the rate of temperature rise to 1.7 degrees Celsius
per century, dwarfing the natural background rate,” ANU climate
professor Will Steffen said in a statement on the university’s news page. Read more (2/13/17 3:31 PM)