Earth’s Mirror

Landsat shows us the home planet, warts and all.

Emptying into the Arctic Ocean, the 2,800-mile-long Lena River in Siberia forms one of the world’s largest deltas. (USGS)
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In 2007, Bindschadler led a team to create, from more than 1,000 Landsat 7 images made between 1999 and 2003, the first, true-color, high-definition map of Antarctica. With the Landsat Image Mosaic of Antarctica, anybody with a laptop can cruise around Earth’s emptiest place. Bindschadler got a surprise when the first scientific use of the map turned out to benefit not glaciologists but biologists: Scientists with the British Antarctic Survey used LIMA to find Emperor penguin rookeries. The recorded spectral signatures allowed the biologists to differentiate the penguin guano from ice, snow, and rock.

Nowhere on Earth has change been more obvious than in the planet’s tropical rainforests, and Brazil has been the world leader in measuring deforestation and publishing the results. “Brazil decided not to wait for the world to tell them what’s going on,” says Tom Loveland. Every year, Brazil’s National Institute for Space Research collects images from Landsat and other satellites, creates a map of Amazonian forests, and reports the statistics to the world. With these results, says Loveland, the institute has evidence of the effectiveness of their policies for protecting timberland; recent statistics show they’re starting to work.

That means that the loss of forests is being slowed, not that the forests are being replaced. “That’s all you can do,” says Matt Hansen. “How long does it take to re-establish a primary rainforest, with all of its richness? All you can do is lose it. When it’s cleared, it’s cleared. That’s the way we treat it, and that’s the way Brazil treats it.”


If the world’s forests are to survive, local governments must devise equitable plans for managing the competing demands on them. In the Democratic Republic of the Congo, almost 50 million people, two-thirds of the population, live in rural areas and rely on the land for livelihood. Because villagers clear forestland for farms and depend on firewood for fuel, the forests are gradually declining.

Since 2004, the African Wildlife Foundation has led a program that involves local communities in plans to protect forests from loss in the north central part of the country, home to a large population of bonobo apes as well as other species. Working with the project, Janet Nackoney, a research assistant professor at the University of Maryland, visited the Maringa-Lopori-Wamba Landscape and helps create maps to be used for land-use planning there. Combining Landsat imagery and GPS data with the villagers’ hand-drawn maps of roads, farms, rivers, the locations of chiefs’ houses, and village boundaries, Nackoney and her team help the villagers delineate natural resource management zones that the national government will make formal.

The team has used the satellite imagery to identify corridors joining several wildlife preserves where the loss of forest would endanger the bonobos and other animals. With this information, the team works with the surrounding communities on plans to protect the corridors. “In exchange, our partners help the farmers increase their yields by teaching them about crop rotation and practices to prevent soil erosion,” says Nackoney.

The satellite images (opposite) are also used to monitor deforestation and serve as the basis for maps showing land cover (left). In the Landsat images, darker greens indicate primary forests and swamp forests, where the canopy is intact; agricultural fields are light green; and pink spots show areas that have been newly cleared.


Wildfires destroyed more than nine million acres of forest in the United States last year, a jump over the 10-year average of 6.5 million acres. Most Americans are aware that the U.S. Forest Service works to contain wildfires and protect nearby homes and businesses. But few know that after the fires are out, another kind of firefighting begins.

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