Watch out for the roads

Disaster reduction experts have been calling on countries to “climate-proof” infrastructure like roads, but until now, there have been no studies showing the scale or importance of these interventions.

A recent study by the Intergovernmental Group of Twenty-Four says developing countries will have to spend about US$200-300 billion per year by 2020 to construct public infrastructure - like bridges, power supplies and roads - that are not only environmentally friendly but can also withstand extreme changes in temperature and rainfall.

The study, co-authored by economist Nicholas Stern, says developing countries are spending $0.8-0.9 trillion per year on infrastructure, the majority of which is financed by domestic budgets. To keep up with population growth, cover existing gaps, and make infrastructure climate-resilient as well, countries will have to spend a total of $1.8-2.3 trillion per year by 2020.

Roads critical

A good road network, the basis of most infrastructures, is critical for the development of any country. Roads are essential to trade, transportation, and the provision of food, healthcare and education, promoting economic growth at every level.

''Above certain temperature thresholds, paved roads weaken, causing rapid degradation even under normal or light traffic loads''

Researchers from the Joint Program on the Science and Policy of Global Change, at the Massachusetts Institute of Technology, have joined hands with the United Nations University-World Institute for Development Economics Research (UNU-WIDER) to take a closer look at how climate change could affect roads in the developing world, using Mozambique as an example. 

Food supply in Mozambique is already constrained by the lack of adequate roads linking the big commercial farms in the north to markets in the south. Climate change threatens what roads exist with frequent and intense flooding and high temperatures, researchers said.

Roads are sensitive to extreme heat. "Above certain temperature thresholds, paved roads weaken, causing rapid degradation even under normal or light traffic loads. Perhaps more importantly, a higher frequency and severity of floods will increase road washouts - already a serious problem in many countries," said the study.

The MIT researchers recommend gradually moving towards road designs that accommodate higher temperatures and follow rainfall trends (whether wetter or drier). Rather than embarking on a generalized upgrade of roads, they recommend countries spend their resources on improving "more vulnerable infrastructure, such as unpaved roads in flood-prone zones,” which “could provide positive net benefits in the face of a more extreme future climate".

An earlier UNU-WIDER study found that Africa as a whole could have to spend at least $2.3 billion per year to repair and maintain roads damaged from temperature and rainfall changes related to climate change through to 2100.