An international team of scientists have devised an ambitious global blueprint for where roads around the world should be built in future, based on both economic and environmental considerations.
A new study published in Nature aims to create a planet-wide blueprint to guide future road construction which balances both the needs of future economic development and the preservation of important ecosystems.
The map's development was led by Professor Andrew Balmford from Cambridge's Department of Zoology and Professor William Laurance from James Cook University in Townsville. It is based on the consideration of of two key components: an "environmental-values" layer which assesses the importance of regional ecosystems, and a "road-benefits" layer which examines the potential for roads to raise agricultural production.
According to Balmford and Laurance, the joint consideration of these two factors has enabled them to identify those areas where the construction of new roads will produce the greatest amount of benefit, those areas where roads should not be built, and those areas "where potential costs and benefits are both sizeable."
The production of the map involved a long, laborious process. Laurance, Balmford, and a team of colleagues from Harvard, Cambridge, Melbourne and Minnesota first spent nearly two years identifying the location of the world's key ecosystems whose conservation should be prioritised.
They then sought to identify areas where road construction would have the greatest positive impact on regional economic development, which were generally determined to be those areas that engaged in low-yield agriculture yet were situated at a reasonable distance from urban markets. These areas can be found throughout the globe, including Central Asia, Central America, and Atlantic coast of South America.
The study's authors say they focused on agriculture because of the projected surge in global food demand, which is expected to double by mid-century. Roads are critical to fostering the growth of the agricultural sector, not just because they enable producers to convey their crops to markets or key logistics points, but also because they facilitate the delivery of critical inputs such as fertilisers.
According to the authors of the study, the conclusion to be drawn from the map they've produced is positive, proving that there are still large swathes of the planet where agriculture can be improved without taking a severe toll on the environment.
Laurance hopes the global road map would enable governments and international funding bodies to make better decisions with respect to future road planning and construction.
"So much road expansion today is unpinned or chaotic," he said. "We badly need a more proactive approach. It's vital because we're facing the most explosive era of road expansion in human history."
According to the authors of the study, over 25 million kilometres of new roadways are expected to be built around the globe by mid-century, a distance roughly equivalent to 600 times the Earth's circumference.