Our physical impact on the planet - so-called ‘human footprint’ - has not grown as rapidly as the human population between 1992 and 2009, finds a study in Nature Communications this week. However, the study shows that the human footprint expanded the most in places with the highest biodiversity, as well as in lower-middle-income countries.
The human footprint refers to the extent of humans’ physical impact on the natural environment, primarily through the conversion of land for urbanization or agricultural purposes. This footprint was initially measured and mapped on a global scale using data available in the 1990s, but human population size and the world economy have grown since then, calling for an updated human footprint map.
Oscar Venter and colleagues used published datasets on various human impacts (built surfaces, roads, crop and pasture land, nighttime lights, and human population density) in order to generate a new global map of the human footprint, and to measure the change in footprint over a 16-year interval. They found that, across the globe, the overall human footprint grew by 9% between 1992 and 2009, despite a 23% growth in human population size over the same time period. Although it was very rare for the footprint to decline at any location, the rate of increase was smaller for wealthier countries. In addition, regions with large numbers of threatened species were associated with a high degree of human pressure. Only a few places with many threatened species remained impact-free, including central Borneo and the Central Asia Deserts.
Despite identifying places where human impact has decreased in the studied timeframe, this study also highlights that future challenges for balancing environmental and societal needs may be concentrated in countries with emerging economies or in the Earth’s most biodiverse regions.
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