Source: Charlene Porter, U.S. Embassy
Population analysts estimated that world population exceeded 7 billion in October and now marches onward to 8 billion. With every passing moment, a scientific program operated by NASA and the U.S. Geological Survey (USGS) collects data that will help determine how rapidly humans are using the planet’s resources and whether those resources will meet the needs of an ever-growing population.
The Landsat program began in 1972, and since then seven Earth-observation satellites have been launched. Two remain in orbit today—Landsats 5 and 7—and the 40th anniversary of the program will be noted as scientists and engineers work to ready Landsat 8 for launch in 2013. More than 3 million images of the Earth’s surface have been collected and archived through the life of the program. This massive database is available for free, and is tapped by millions of people each year in more than 180 countries.
“This easily accessible, impartial record is really the great enabler in understanding Earth resources management,” said Thomas Loveland, senior scientist at the U.S. Geological Survey’s Earth Resources Observation and Science (EROS) Center at a scientific symposium November 16.
A single Landsat images the entire Earth in 16 days, Loveland said, recording images of the same spot on the surface at regular intervals. “It gives us the opportunity to look at the planting of our crops, watching their development through the season and estimating the extent of harvest,” Loveland said. “But it also lets us look at the growth of cities over time, changes in our forests, and monitoring the impact of floods, fires and other disasters.”
Scientists are also able to use the data to help governments better understand resources, such as water and forests, and use that information to make better plans for use and conservation of the resources.
Europeans have also made important use of the data provided by Landsat, according to Alan Belward of the European Commission Joint Research Centre. His agency has been working with about 30 sub-Saharan African governments to create an accurate accounting of the amount and rate of African land conversion from natural vegetation to agriculture. Their analysis has determined that about 50,000 square kilometers are being converted each year.
“It is big,” Belward said. “But at the same time, the population of Africa has about doubled in that time. So there’s less agriculture acreage per person now than there was in the 1970s. This pressure on the land is relentless.”
Belward expects the pressure on land use to remain relentless, and says the Landsat program must remain in place to keep track of the changing landscape.
Matthew Hansen also taps into Landsat data to watch changing land use on a global scale in his role as a remote sensing scientist at the University of Maryland. He said the free availability of Landsat data is going to encourage greater understanding of land use. “We’ve democratized the process by having all these data freely available around the world,” he said.
Hansen foresees that more and more countries will be using the data to gain a better understanding of planetary systems such as the carbon cycle, climate change, biodiversity, cropping systems and hydrology. He suggests a new era of explosive activity in this area is just beginning.
NASA and USGS are planning on a launch of Landsat 8 in early 2013, which may be none too soon. Since the November 16 symposium, USGS reports that Landsat 5 is starting to malfunction, and it appears the craft is reaching the end of its days, leaving Landsat 7 to work alone in monitoring the Earth’s surface.
Though the U.S. Congress has not authorized funding to begin planning for Landsat 9, Loveland is optimistic that the program will persist.
+ “Earth Observation Grows in Importance as Landsat Turns 40,” U.S. Embassy
Safeguarding freshwater resources is crucial, and while scientists use a variety of ground-based techniques to gauge water quality, the Landsat program has provided water quality data from orbit for decades.