Roads of destruction: we found vast numbers of illegal ‘ghost roads’ used to crack open pristine rainforest

• In an article published today in Nature, my colleagues and I show that illicit, often out-of-control road building is imperilling forests in Indonesia, Malaysia and Papua New Guinea.
• Once roads are bulldozed into rainforests, illegal loggers, miners, poachers and landgrabbers arrive.
• Once they get access, they can destroy forests, harm native ecosystems and even drive out or kill indigenous peoples.
• All nations have some unmapped or unofficial roads, but the situation is especially bad in biodiversity-rich developing nations, where roads are proliferating at the fastest pace in human history.

Mapping ghost roads

• This workforce then spent some 7,000 hours hand-mapping roads, using fine-scale satellite images from Google Earth.
• For starters, unmapped ghost roads seemed to be nearly everywhere.
• In fact, when comparing our findings to two leading road databases, OpenStreetMap and the Global Roads Inventory Project, we found ghost roads in these regions to be 3 to 6.6 times longer than all mapped roads put together.

• When ghost roads appear, local deforestation soars – usually immediately after the roads are built.
• We found the density of roads was by far the most important predictor of forest loss, outstripping 38 other variables.

Roads and protected areas

• 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.
• 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.

Hidden roads and the human footprint

• 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.
• 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.

Artificial intelligence

• 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.
• 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.
• Once we have this information, we can make it public that so authorities, NGOs and researchers involved in forest protection can see what’s happening.

Distinguished Professor Bill Laurance receives funding from the Australian Research Council and other scientific and philanthropic bodies. He is a former Australian Laureate and director of the Centre for Tropical Environmental and Sustainability Science at James Cook University.