Looking at pictures of our planet from space is a humbling experience.
From so far up, most of humanity seems to melt away. You can't see the president or that guy who cut you off on the highway this morning. All you see is the natural world as it truly is. Unfortunately, there are times when our actions impact the Earth in such a large way that the effects can be seen from outside our atmosphere.
These images from NASA's Earth Observatory highlight some of the ways our planet has been visibly changed by human activity.
Spoiler alert: it's not always pretty.
Reduction of snowpack in Sierra Nevada:
The snow that builds up during the winters in Sierra Nevada serves a very important purpose. When it eventually melts during spring and summer, the runoff goes into reservoirs that provide most of the freshwater for residents in California. The image on the left was taken in March 2010, when the snow was plentiful enough to provide enough water to meet the demands of the reservoirs. The image on the right was taken just five years later, in the midst of one of the worst droughts in California history. With such limited snowfall, there hasn't been enough runoff to provide water for Californians. At the time of this writing, California has enacted water rations due to the shortage.
According to the EPA, such drastic changes in snowpack are indicators of climate change, which is driven in a large part by human activity.
Haze of pollution over China:
China's population of over 1.3 billion represents 18.9 percent of all humans on the planet. With such a densely populated and industrialized country, it probably doesn't come as a huge surprise that it generates a considerable amount of pollution. These images, taken only 11 days apart, reveal just how wildly air quality can vary in a short amount of time. Such heavy smog doesn't just affect the environment, but as the EPA warns it can reduce lung function, negatively affecting those with asthma, bronchitis, and emphysema.
China's pollution being carried out to sea by the wind:
Of course, our planet is incredibly dynamic. The heavy haze of pollution that forms over China doesn't stay in one place. Weather patterns carry the particulate matter out to sea and to other countries, where it affects distant ecosystems and threatens human health as well.
Rampant deforestation of the Amazon:
The Amazon rainforest is a 3.4-million-square-mile area of land that is home to 10 percent of all of the biodiversity on the planet. The 400 billion trees not only provide oxygen, but help fix atmospheric carbon and reduce global warming. About 20 percent of the rainforest has been lost to deforestation in the last 40 years. These images, taken 12 years apart, show the extent of that loss.
Using wildfire to clear land in the Amazon:
Using machinery to cut down trees can be expensive and time-consuming, which is why fires are often used to clear land. This not only destroys trees, it disrupts the habitats of millions of species of animals and plants. The huge fires that are set in the Amazon are visible from the International Space Station, as this image from August 2014 shows.
Collapse of an Antarctic ice shelf:
The effects of climate change are rarely seen as clearly as with the collapse of polar ice. In recent years, seasonal temperatures have been increasing so dramatically that large chunks of glacial ice are breaking off and dissolving into the ocean. The picture on the left, taken in January 2002 (which is the middle of summer in Antarctica) shows the Larsen B Ice Shelf intact, but only a few months later (April, 1), 250 square miles of ice have shattered off.
Dubai's urbanization and manmade palm tree island:
Dubai's dramatic urbanization between 2000 (left) and 2011 (right) can clearly be seen from space. Not only has the coastal area become more industrialized, but the addition of the palm-tree-shaped island is hard to miss. These islands were made by taking sand from the ocean floor and artificially shaping them. Dredging the sand destroyed the habitats of those organisms living on the bottom of the sea — including coral reefs, oyster beds, and marine plant species.
Changes to China's Yellow River:
While the Yellow River has changed courses on its own over the years, these images show what 20 years of human intervention can do. The flow of water was diverted in order to protect oil fields, and to use the water for agricultural irrigation. Though it seems to be working well for the people living in the area, affecting the environment in such a dramatic way has altered the surrounding ecosystem, as is clearly visible in these pictures.
Lakes of the Mongolian Plateau are drying up:
Due to effects of human-influenced climate change, including higher temperatures and decreased rainfall, the lakes that make up a significant portion of the water supply in the Mongolian plateaus have decreased considerably between August 2001 (image on left) and August 2006 (image on right). NASA data show that overall, these lakes have decreased by 30 percent over the last 30 years.
Columbia Glacier in Alaska is receding:
In another devastating blow to glacial ice, the Columbia Glacier in Alaska has been on a rapid decline for the last 35 years, according to NASA. The image on the left shows the glacier in 1986, and the one on the right shows how far back the ice has receded as of 2014. From one image to the next, a total of 12 miles of ice has broken off into the ocean. Not only is this representative of how powerful human-driven climate change is, but it impacts the ecosystem for local organisms and contributes to overall sea level rise as well.
Sierra Nevada: NASA Earth Observatory/Jesse Allen
China pollution change: NASA, Jeff Schmaltz, LANCE MODIS Rapid Response
China pollution out to sea: SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE
Amazon destruction: Goddard Space Flight Center
Antarctic ice shelf: NASA Earth Observatory