Landscape change between 1992 and 2015. White reflects little change. Darker shades reflect the greatest rate of change in each category. Credit: Tomasz Stepinski/UC
A new map that stitches together 24 years of satellite observations provides a detailed look at striking changes in land use and widespread environmental degradation. According to the map, 22 percent of Earth’s habitable surface has been significantly altered since 1992, primarily from agricultural-driven deforestation.
“We already knew about deforestation or wetland loss or increasing urbanization,” said Tomasz Stepinski, a geographer at the University of Cincinnati and a co-author of the new map. “But now we can see exactly where all of that is happening… What makes this so depressing is that it’s examining a timescale that is shorter than our lifetime.”
The map illustrates widespread losses of wetlands in the Southeastern United States; the rapid disappearance of the Aral Sea, which “dried up in the 1990s after farmers in Kazakhstan and Uzbekistan diverted its tributaries for cotton fields,” a press release explained; deforestation in the tropics; and the expansion of the Sahara Desert.
The data also offers context for recent sociopolitical events, such as the caravan of immigrants moving north toward the U.S. border. Many of the migrants come from Guatemala, fleeing years of crop failure. But Stepinski and his colleagues’ new map also shows how widespread deforestation has reshaped the country.
The scientists analyzed nine types of land-use change — deforestation, development, and agriculture, for example — in 5.5-mile-square plots across the globe using satellite images collected by the European Space Agency between 1992 and 2015. They then used three shades of color for each land use type to identify the extent of change. The scientists recently published their new map in the International Journal of Applied Earth Observation and Geoinformation.
“I hope this map will make people more aware of the human impact on our planet,” geographer Jakub Nowosad, lead author of the new study, said in a statement. “As a society, we need to be better informed of the scale of changes we make to the Earth, and in my opinion, this awareness can influence future changes in environmental policies.”
