Urbanization, Export Crops Drive Deforestation
In Reversal, Land Is Cleared for Global Trade and Big Cities, Says Study
Clearing for large-scale agriculture, Mato Grosso, Brazil
(Doug Morton/Goddard
Urbanization, Export Crops Drive Deforestation
In Reversal, Land Is Cleared for Global Trade and Big Cities, Says Study
Clearing for large-scale agriculture, Mato Grosso, Brazil
(Doug Morton/Goddard Space Flight Center)
The drivers of tropical deforestation have shifted in the early 21st century to hinge on growth of cities and the globalized agricultural trade, a new large-scale study concludes. The observations starkly reverse assumptions by some scientists that fast-growing urbanization and the efficiencies of global trade might eventually slow or reverse tropical deforestation. The study, which covers most of the world’s tropical land area, appears in this week’s early edition of the journal Nature Geoscience.
Deforestation has been a rising concern in recent decades, especially with the recognition that it may exacerbate climate change. Studies in the late 20th century generally matched it with growing rural populations, as new roads were built into forests and land was cleared for subsistence agriculture. Since then, rural dwellers have been flooding into cities, seeking better living standards; 2009 was recorded as the first year in history when half of human lived in urban areas. Large industrial farms have, in turn, taken over rural areas and expanded further into remaining forests, in order to supply both domestic urban populations and growing international agricultural markets, the study suggests.
“The main drivers of tropical deforestation have shifted from small-scale landholders to domestic and international markets that are distant from the forests,” said lead author Ruth DeFries, a professor at the Earth Institute’s Center for Environmental Research and Conservation. “One line of thinking was that concentrating people in cities would leave a lot more room for nature. But those people in cities and the rest of the world need to be fed. That creates a demand for industrial-scale clearing.”
DeFries and her colleagues analyzed remote-sensing images of forest cover across 41 nations in Latin America, Africa and Asia from 2000-2005, and combined these with population and economic trends. They showed that the highest forest losses were correlated with two factors: urban growth within countries; and, mainly in Asia, growth of agricultural exports to other countries. Rural population growth was not related.
In recent years, tropical countries have been supplying growing amounts of palm oil, soybeans, sugar, meat and other processed products to distant markets 