Getting Road Expansion on the Right Track: A Framework for Smart Infrastructure Planning in the Mekong.

Andrew Balmford,Cath Tayleur,Mingcheng Wang,Jianchu Xu,Ben Phalan,Christine O’Connell,Huafang Chen,Georgina Mace

doi:10.1371/journal.pbio.2000266

Abstract

The current unprecedented expansion of infrastructure promises to enhance human wellbeing but risks causing substantial harm to natural ecosystems and the benefits they provide for people. A framework for systematically and proactively identifying the likely benefits and costs of such developments is badly needed. Here, we develop and test at the subregional scale a recently proposed global scheme for comparing the potential gains from new roads for food production with their likely impact on biodiversity and ecosystem services. Working in the Greater Mekong—an exceptionally biodiverse subregion undergoing rapid development—we combined maps of isolation from urban centres, yield gaps, and the current area under 17 crops to estimate where and how far road development could in principle help to increase food production without the need for cropland expansion. We overlaid this information with maps summarising the importance of remaining habitats to terrestrial vertebrates and (as examples of major ecosystem services) to global and local climate regulation. This intersection revealed several largely converted yet relatively low-yielding areas (such as central, eastern, and northeastern Thailand and the Ayeyarwady Delta), where narrowing yield gaps by improving transport links has the potential to substantially increase food production at relatively limited environmental cost. Concentrating new roads and road improvements here while taking strong measures to prevent their spread into areas which are still extensively forested (such as northern Laos, western Yunnan, and southwestern Cambodia) could thus enhance rural livelihoods and regional food production while helping safeguard vital ecosystem services and globally significant biological diversity.

Highlights

The world is undergoing an unprecedented expansion of human infrastructure
Proposals for new infrastructure in developing countries are typically muted on its environmental impacts, while environmentalists typically say little about its potential benefits for people
Our analysis suggested substantial potential for increasing food production in the Greater Mekong Subregion (GMS) through closing existing yield gaps, without any change in the area under production

Summary

Introduction

The world is undergoing an unprecedented expansion of human infrastructure. For example, more than 450 new hydropower dams are planned for the Amazon, Congo, and Mekong basins alone [1]. A recent report from the International Energy Agency states that by 2050 the world will build an estimated 335,000 km of new railway tracks and 25 million km of new road lanes—the great majority in developing countries [2,3]—while the newly established Asian Infrastructure Investment Bank alone has already built up US$100 billion in capital for investments in the Asia-Pacific region, and the New Development Bank has starting capital of US$50 billion [4]. New infrastructure can bring substantial benefits to people [6,7,8,9,10] but if poorly planned can impose very significant environmental costs. There is instead a need to develop a robust, spatially explicit, and proactive framework for estimating probable environmental costs of planned infrastructure and weighing these up against likely benefits [18]

Methods

Results

Discussion

Conclusion