Footprint smashing slightly less
Humans appear to have slowed down the rate at which they are destroying the planet.
A paper in Nature Communications this week finds our physical impact on the planet — the so-called ‘human footprint’ — has not grown as rapidly as the human population between 1992 and 2009.
But that is really taking a positive view on the fact we continue to smash the parts of the world with the highest biodiversity, and lower-middle-income countries as well.
The ‘human footprint’ refers to the extent of humans’ physical impact on the natural environment, primarily through the conversion of land for urbanisation 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.
Researchers including experts from the University of Queensland and James Cook University used published datasets on various human impacts (built surfaces, roads, crop and pasture land, night-time 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 per cent between 1992 and 2009, despite a 23 per cent 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, the 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.
The authors say that while environmental impacts may not be tracking the exact growth rate of economies, they are still frighteningly extensive.
“Our maps show that three quarters of the planet is now significantly altered and 97 per cent of the most species-rich places on Earth have been seriously altered. There is little wonder there is a biodiversity crisis,” said Dr James Watson, co-author of the study from the University of Queensland and Wildlife Conservation Society.
The experts also expected to see countries with booming economies having expanding environmental impacts, but that was not always the case.
“It is encouraging that countries with good governance structures and higher rates of urbanization actually grew economically while slightly shrinking their environmental impacts of land use and infrastructure. These results held even after we controlled for the effects of international trade, indicating these countries have managed in some small measure to decouple economic growth from environmental impacts,” said co-author Dr Eric Sanderson.
“Sustainable development is a widely espoused goal, and our data demonstrates clear messages of how the world can get there,” said Dr Oscar Venter of the University of Northern British Columbia.
“Concentrate people in towns and cities so their housing and infrastructure needs are not spread across the wider landscape, and promote honest governments that are capable of managing environmental impacts.”