Before building sustainably, let’s define ‘sustainability’

At a recent address to the Senate, Transportation Secretary Pete Buttigieg summarized the Biden administration’s approach to infrastructure in a succinct statement. “The truth is,” he proclaimed, “every infrastructure decision is already, inevitably, a climate decision.”

The response to this stance, however, has been anything but succinct. Instead, it has prompted considerable debate in Congress over infrastructure spending — with plenty of hand wringing involved. The reason for this backlash is simple: it presents a challenge.

In one sentence, it acknowledges the complexity of infrastructure and its tremendous influence on our lives. In essence, Buttigieg stated something obvious to many, yet imperceptible to others: infrastructure is more than infrastructure.

Far beyond supporting vehicles, infrastructure can dictate our health, the economic opportunities afforded to communities and, above all, climate change. As the nation confronts challenges of congestion, growth, equity and climate change, infrastructure is beginning to be seen not just as a utility, but as a solution.

And so, since infrastructure inevitably sustains nearly every aspect of society, it’s fitting the White House is committed to building sustainable infrastructure. That begs the question though: what is sustainability? And, moreover, does Biden’s infrastructure investment truly address it?

Let’s start by defining sustainability. While it may seem intuitive, it’s worth further investigation. Here’s a basic definition: the act of building our systems to last.

In the context of the environment, it refers to how society can grow and sustain itself without exhausting the planet’s finite resources. Broadly speaking, though, sustainability can apply to virtually every aspect of society, from the long-term viability of federal spending to rising health care costs. But setting a path to achieving sustainability is complex.

In the case of infrastructure, that means considering the long-term impacts of all choices. Questions that can arise include: Will the infrastructure be durable? How well will it suit future transportation needs? Will it continue to effectively serve communities? Is it fiscally responsible? And of course, will it sustain the planet?

There’s a myriad of solutions that can answer these questions. And often, those solutions overlap. To get an idea of how, we can look at the nation’s road network — which recently received nearly a failing grade from the American Society of Civil Engineers.

Currently, the common practice in the U.S. is to maintain roads with a short-term mindset that minimizes risk and costs on a year-to-year basis. When we consider the growing backlog of repairs and the nation’s highly degraded roads, it becomes clear that this strategy is unsustainable.

At the MIT Concrete Sustainability Hub (MIT CSHub), we’ve sought to identify and highlight sustainable solutions. Our research has found that using a mix of materials and a combination of long-term and short-term strategies can reduce roadway emissions, lower costs and improve road quality over time.

The takeaway here is that issues of fiscal, environmental, and functional sustainability are all interrelated — and can often be attained simultaneously with the right approaches.

One of those approaches is the consideration of risk. The future is uncertain, and prices change along with needs and demand: a sustainable system should anticipate those risks. Yet, the way we build and maintain infrastructure today avoids certain risks entirely.

For instance, the procurement of construction materials is often based on current prices and needs without considering the risk of changes over time. Paving a road with one material might seem economical today but, amidst a changing climate and increased demand, that might not be the case in 10 years. When we let those risks inform decision-making, it’s possible to lower costs and improve infrastructure over time.

The Biden administration seems to understand these concerns. Its infrastructure plan prioritizes not only fixing roads, bridges and main streets first but “fixing them right.” To achieve this, implementing a variety of materials over different time frames and explicitly considering risks should be a part of the solution.

Of course, the biggest risk facing infrastructure today is climate change. We need to use resilient materials in the right contexts to mitigate the risks that arise from a warming and increasingly turbulent planet. Again, the same approaches — long-term perspectives and risk-informed decisions — can help attain resilient infrastructure. It’s direly needed.

Across the country, hazard risks remain underestimated while the long-term costs and benefits of resilient construction are not widely known by the general public. Our research at MIT CSHub has found that in hazard-prone areas like New Orleans, homeowners could see a full return on investments in hazard mitigation in as soon as 2 years. For an average homeowner in hurricane-prone South Florida, an additional initial investment of as much as 17 percent in resilient construction will pay for itself. In this sense, hazard resilience is also a form of sustainability since it promotes a durable built environment in the face of long-term risks.

What’s more, resilience will be necessary to sustain the nation’s myriad communities. As the American Jobs Plan notes, “People of color and low-income people are more likely to live in areas most vulnerable to flooding and other climate change-related weather events…[and] are less likely to have the funds to…recover.” As inequality continues to increase, infrastructure decisions will only prove sustainable if they can promote a more equitable society.

The American Jobs Plan’s extensive investments in equity and resilience — particularly a tax credit for low- and middle-income folks for investments in hazard mitigation — acknowledge how sustainable infrastructure begets sustainable communities.

All of this is to say that sustainability is more than a buzzword. While it’s a simple concept, its manifestations are myriad — yet intersectional. The same solutions that address the functional sustainability of our infrastructure can also address environmental and social sustainability. As we embark on a historic infrastructure plan it’s important to keep this definition in mind. Thankfully, it seems to be at the heart of Buttigieg’s agenda. 

Jeremy Gregory, Ph.D., is a research scientist at MIT and the executive director of the MIT Concrete Sustainability Hub (CSHub). He studies the economic and environmental implications of engineering and system design decisions, particularly in the area of materials production and recovery systems. 

Research from the MIT CSHub is sponsored by the Portland Cement Association and the RMC Research and Education Foundation.