The Promise of Sustainable Infrastructure

Sustainable infrastructure isn’t just about building up — it’s about building smarter, and taking advantage of natural ecosystems and processes, as well.

The words sustainable infrastructure may bring to mind images of complex, man-made irrigation systems designed to whisk water away during hurricanes and typhoons. But what if we could create a sustainable infrastructure using something much simpler? Like mangroves, for example.  

In 2013, when Typhoon Haiyan (also known as Yolanda), tore its way through the Philippines, coastal mangrove forests kept a serious natural catastrophe from becoming an outright climate calamity. The mangroves acted as a natural storm barrier for the poor, largely underdeveloped islands, significantly minimizing the scale of the damage to the economy (which was estimated, nonetheless, at over $14 billion) — and to human lives. 

Mangroves have been called “key in the climate change battle.” Not only do they prevent coastal erosion and protect against natural disasters, they also serve as natural “blue carbon” sinks that reduce greenhouse gas emissions. And so, after the storm, the Filipino government decided to invest in replanting mangroves along the coastline — shuffling more than $8 million into its Department for Environment and Natural Resources in order to do so. 

Mangrove forests in the Philippines are just one example of the key role existing natural ecosystems can play in developing climate-resilient infrastructure for the 21st century. While LEED-certified buildings and elaborate cycling networks in advanced European economies are one way of creating a more sustainable future (a “gray,” or built, one), mangroves, urban wetlands, and salt marshes are a less-discussed, but equally important element (a “green,” or natural, one) in the fight. 

Addressing climate change will require increasing investment in both green and gray sustainable infrastructure as the global population expands from the current 7.7 billion to 9.7 billion in 2050 — with the majority of that growth in the urban areas of low- to middle-income countries. The OECD has estimated that in order to meet the United Nations Sustainable Development Goals (SDGs), investment in sustainable infrastructure will need to increase by about 30 percent by 2030. By that same year, the global need for water supply infrastructure will also triple — from about $6.7 trillion to $22.6 trillion. 

Infrastructure is a through-line in the SDGs, either directly or indirectly affecting more than 70 percent of all SDG targets. The focus of SDG 9 is particularly clear: it calls for “quality, reliable, sustainable and resilient infrastructure…with a focus on affordable and equitable access for all.” 

Ensuring equity and affordability may be the toughest challenge of all. 

In developing countries, investment in sustainable infrastructure could represent 4.5 to 8 percent of GDP by 2030. Yet these countries are the ones most affected by existing infrastructure gaps, and they have the least financial capacity to address them. To satisfy the basic needs of their people they will need to invest in infrastructure on a massive scale, but without using the fuel and energy-intensive methods that industrialized Western European and Asian countries have used. 

This is where involving local communities in the development and management of sustainable infrastructure, and taking advantage of natural ecosystems, can be of importance. 

Often, green and gray infrastructure can work together — much as governments and the private sector do in public-private partnerships. In Vietnam, for example, a World Bank project to combine the construction of sea dikes with the replanting of mangrove forests in the Mekong Delta has reinforced the coastal ecosystem and revitalized local fishing communities. China is developing a number of its coastal metropolises into “sponge cities” that use a combination of built infrastructure techniques (such as green roofs and porous pavements) and natural ones (such as bioswales and wetlands) to address the future impacts of climate change. 

Combining green and gray infrastructure can lower construction costs and increase social inclusion while reducing poverty. As is often the case with climate-related initiatives, however, it can be difficult to convince stakeholders that investing in sustainable infrastructure now rather than later will avoid future damages, and will have positive externalities, or “co-benefits,” for local populations. 

But the long-term economic and environmental benefits of sustainable infrastructure are clear. The OECD estimates that a $50 billion investment in flood defenses now would reduce the losses from flooding in 2050 from $1 trillion to $60 billion per year. UN Secretary-General António Guterres has perhaps put it best: “For every dollar invested, six dollars can be saved.” 

A sustainable future is well worth the investment.