Roads can cause a lot of damage. Even when they’re relatively narrow, they can require you to clear swathes of fields and forests. Problem is, to keep up with the world’s ever-growing population, it looks like we might need another 25m km of them worldwide by 2050.

So a group of environmental scientists and zoologists from Cambridge and Australia’s James Cook University have used information on the world’s ecosystems to figure out how to install all those roads without unnecessarily damaging the environment. This article on the research, published on the Cambridge University website, explains how it works:

“The map has two components: an ‘environmental-values’ layer that estimates that natural importance of ecosystems and a ‘road-benefits’ layer that estimates the potential for increased agriculture production via new or improved roads. 

“The authors of the new study… write that by combining these layers they have identified areas where new roads have most potential benefit, areas where road building should be avoided, and conflict areas ‘where potential costs and benefits are both sizable’.”

The scientists focussed on rural areas as the most likely targets for road expansion: world food demand is expected to double by 2050, and agriculture yields are limited by lack of good transport links between farms and urban areas. However, building roads is particularly tricky in the countryside – they can destroy whole ecosystems through pollution, noise and deforestation.

This map from the paper shows these two factors – agricultural potential and environmental values – plotted against each other. The white areas are of very little use to anyone. The black ones, though, have both. Conflict over road planning will most likely be in those areas.

At the moment, the map is purely speculative. But William Laurance, the paper’s lead author, says he hopes it’ll be taken on as a serious recommendation:

“We hope our scheme will be adopted by governments and international funding agencies, to help balance development and nature conservation… So much road expansion today is unplanned or chaotic, and we badly need a more proactive approach.”