‘Ghost roads’ destroying ancient rainforest

‘Ghost roads’ destroying ancient rainforest


Not even parks and protected areas in the Asia-Pacific are fully safe from illegal roads. But safeguarding parks does have an effect. In protected areas, we found only one-third as many roads compared with nearby unprotected lands.

The bad news is that when people do build roads inside protected areas, it leads to about the same level of forest destruction compared to roads outside them.

Our findings suggest it is essential to limit roads and associated destruction inside protected areas. If we can find these roads using satellite images, authorities can too. Once an illegal road is found, it can be destroyed or at least mapped and managed as a proper legal road.

Keeping existing protected areas intact is especially urgent, given more than 3,000 protected areas have already been downsized or degraded globally for new roads, mines and local land-use pressures.

Illicit roads cause destruction worldwide, from carbon emissions from the burning of Amazonian forests for cattle pasture to road building and forest destruction in central Africa, to poaching of rare animals such as this forest elephant killed by poachers near a Congo Basin road. 

The impact we have on the planet differs from place to place. To gauge how much impact we’re having, researchers use the human footprint index, which brings together data on human activities such as roads and other infrastructure, land uses, illumination at night from electrified settlements and so on. 


You can use the index to make heat maps showing where human impacts are most or least pronounced.

We fed our ghost road discoveries into the index and compared two versions for eastern Borneo, one without ghost road information and one with it. The differences are striking.

When ghost roads are included in mapping the human impact on eastern Borneo, areas with “very high” human disturbance double in size, while the areas of “low” disturbance are halved. 

Researchers investigating other biodiversity-rich developing regions such as Amazonia and the Congo Basin have found many illegal unmapped roads in those locales too.

Ghost roads, it seems, are an epidemic. Worse, these roads can be actively encouraged by aggressive infrastructure expansion schemes — most notably China’s Belt and Road Initiative, now active in more than 150 nations.


For now, mapping ghost roads is very labour-intensive. You might think AI could do this better, but that’s not yet true – human eyes can still outperform image-recognition AI software for mapping roads.

At our current rate of work, visually mapping all roads – legal and illicit – across Earth’s land surface just once would require around 640,000 person-hours (or 73 person-years) to complete.

Given these challenges, our group and other researchers are now testing AI methods, hoping to provide an accurate, global-scale mapping of ghost roads in close to real-time. Nothing else can keep pace with the contemporary avalanche of proliferating roads.

We urgently need to be able to map the world’s roads accurately and often. Once we have this information, we can make it public so that authorities, NGOs and researchers involved in forest protection can see what’s happening.

Without this vital information, we’re flying blind. Knowing what’s happening in the rainforest is the first step to stopping the destruction.

This Author 

Bill Laurance is a former Australian Laureate and director of the Centre for Tropical Environmental and Sustainability Science at James Cook University.


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