As the world tackles climate change, it faces a seemingly intractable problem. Mitigating climate-disaster will require more resilient construction — and yet the building sector already comprises nearly 40 percent of global emissions.
So, how can we build the resilient infrastructure we need while also eliminating the carbon footprint of construction? At first glance, it might appear that the easiest solution is to do nothing at all.
Limiting the development of new construction, for instance, would reduce building sector emissions while slowing humanity’s encroachment on hazard-prone regions.
But, of course, such an approach is as myopic as it is impossible. Over the next 50 years, the number of city dwellers worldwide will increase from 5 billion to 7 billion. Ensuring that these new residents in some of the world’s most climate-vulnerable regions have access to sanitary, safe buildings is crucial — and will require extensive, resilient construction. Even here in the U.S., the need for new infrastructure is growing: the Biden administration has made “building back better” a huge priority.
So, what can we do to manage the impacts of this inevitable development? The simple, if obvious, answer is to build wisely. But the more important point is to understand that sustainability and resilient construction are, in fact, totally compatible.
This becomes clear when we actually define these two ubiquitous terms. As its name implies, “sustainability” means designing systems to last in the face of stresses — systems that can sustain the planet, society and the economy. The definition of resilience is fundamentally similar. Encompassing far more than “rugged” design, “resilience” means designing to resist and, most importantly, rapidly recover from a disaster.
In essence, these two concepts, resilience and sustainability, have the same goal: ensuring long-term viability in the face of challenges. When we consider them in practice, their alignment becomes even clearer.
A resilient structure, for instance, can withstand many hazards over its life, significantly mitigating the costs associated with hazard repair. At the MIT Concrete Sustainability Hub, we have found that investments in resilient construction pay for themselves in just a couple of years in hazard-prone regions.
These investments can be as straightforward as storm shutters and stronger roof-to-wall connections or as stringent as elevated structures, concrete walls, and fireproof materials. Given the massive losses hazards will likely inflict in the coming century, resilient construction makes clear financial sense.
But it also makes environmental sense. In the aftermath of a disaster, poorly built infrastructure leads to immense amounts of, often toxic, waste — as well as a large demand for resources and reconstruction that will only increase the environmental impacts of the building sector. In that sense, to build resiliently is also to build sustainably, limiting unnecessary construction and waste.
Resilient construction can also be inherently sustainable. New construction is more energy-efficient, and that’s especially the case with resilient materials. We’ve found that resilient construction can have around 5 to 10 percent lower lifetime impacts due to energy efficiency — despite having up to a 30 percent greater initial impact from materials and construction.
The same is true for infrastructure. Durable, paving materials can reduce vehicle emissions and mitigate hazards like the urban heat island effect when implemented in the right context. Moreover, designing road networks to endure future risks like price and budget changes — not to mention hazards — allows agencies to reduce their emissions, lower costs and improve performance over the long term.
All of this is to say that the construction of a resilient built environment does not conflict with sustainability. In fact, it’s clear these two goals are more than harmonious — they are synergistic.
Even still, that doesn’t preclude the need to completely eliminate building sector emissions: We will still need to use the lowest emitting materials. To ensure that this happens, governments, industries and academia must collaborate. The potential solutions are myriad.
We can start by reimagining how governments procure sustainable materials. Currently, many states compare the environmental impacts of construction products with tools that were never intended to facilitate comparisons. By creating a better standard, it will be easier for governments to select the greenest materials — and for manufacturers to compete to lower their impacts.
However, we’ll need more than just competitive, transparent markets. The development of innovative materials will also require a comprehensive array of investments, particularly around carbon capture, which is currently prohibitively expensive. In the case of concrete — which is a ubiquitous, affordable and resilient construction material — carbon capture will be essential to eliminating emissions.
Thankfully, the Biden administration’s latest proposal acknowledges these needs.
In addition to investing tens of billions of dollars towards resilient construction, the plan aims to improve the nation’s infrastructure by “fixing it right.”
Our research has already found that this kind of long-term, strategic approach inherently tends to produce resilient and sustainable outcomes by managing risk and minimizing construction actions. But above all, the plan prioritizes the procurement and innovation of low-impact construction materials, including concrete, which the nation will need to build resiliently.
As the world experiences unprecedented growth, balancing resilient construction and environmental sustainability can seem daunting. But upon closer examination, this trepidation is misplaced: Solutions to climate change can be cumulative, not zero-sum — and that’s especially the case with resilience and sustainability.
Ultimately, we can’t take the easy route and abdicate responsibility: A better future must be built. With the right investments, though, it can be both resilient and sustainable.
Randolph Kirchain, Ph.D., is the co-director of the MIT Concrete Sustainability Hub. His research focuses on the environmental and economic implications of materials selection and deals with the development of methods to model the cost of manufacture and the sustainability of current and emerging materials systems.
Franz-Josef Ulm, Ph.D., is the faculty director of the MIT Concrete Sustainability Hub. His research interests are in the mechanics and structures of materials. His research investigates the nano- and micromechanics of porous materials, such as concrete, rocks and bones and the durability mechanics of engineering materials and structures.
Research from the MIT CSHub is sponsored by the Portland Cement Association and the RMC Research and Education Foundation.