As storms come crashing down around us due to the effects of climate change, our built environment may provide our last bastion of safety. An increasing number of businesses in the architecture, engineering and construction (AEC) space are implementing what’s known as resilient design into buildings and infrastructure.

To learn more, we spoke to Lisa Dickson, associate principal and director of resilience for the Americas at the Arup Group, who works with clients to consider the effects of climate change, among other potential threats, in construction projects.

Flooding and Extreme Rain

According to the National Oceanic and Atmospheric Administration (NOAA), the United States experienced 16 separate billion-dollar disasters in 2017, including Hurricanes Harvey, Irma and Maria, as well as severe storms, drought, wildfires, a crop freeze and inland flooding.

A map displays the 16 billion-dollar disasters that occurred in the U.S. in 2017, which were exacerbated by climate change. (Image courtesy of NOAA.)

Since 1990, the sea level has been rising about 0.12 inches per year, roughly twice as quickly as the average speed of the preceding 80 years. This means that, when tropical cyclones and hurricanes occur, their powerful winds push sea levels to rise even more—a phenomenon known as a storm surge—and drives the water onshore, resulting in much of the death and damage seen during hurricanes like Katrina.

Additionally, warming temperatures can make tropical cyclones and hurricanes more powerful, as these storms gain their energy from warm surface waters. Moreover, warm air holds more moisture, meaning that, with climate change, there will be more extreme rainfall, both within hurricanes and tropical cyclones and without them.

Arup’s Lisa Dickson pointed out that the combination of storm surges and heavy rain add complexities to resilient design. The obvious solution to protect against storm surges would be the construction of a sea wall; however, this can act as a dam for storm water that would need to be flushed out to a nearby bay.

In New York, Arup has helped redevelop 20 acres of post-industrial waterfront on Long Island into Hunters Point South Waterfront Park, where it acts as a storm surge barrier for the largest affordable housing building project in New York City. Located in Flood Zone A, the area in which the park is situated is particularly vulnerable to flooding; however, Hunters Point South has been designed with a 100-year-storm elevation, plus an extra seven feet. Construction on the park was just nearing completion when Hurricane Sandy hit, but, due to the project’s green infrastructure, the park is considered one of the most resilient locations in New York City.

A post-industrial landfill has been restored to include salt marshlands and wetlands using native plants. (Image courtesy of NYC Parks.)

Further combatting flood waters, Hunters Point South features gabions on its Eastern edge. These metal cages plunge six feet below the earth and contain rock fragments that slow storm water and divert it to the sewer. The use of bioswales in the park help filter water pollution and reduce runoff, while a porous pavement also decreases the amount of runoff that is sent to sewers. Additionally, storm and sanitary sewers are separated so that a surge during a storm doesn’t send waste back out into the street.

Gabions consisting of metal cages filled with rocks slow and divert storm water to help limit the effects of flooding. (Image courtesy of Lee Celano, The New York Times.)

Phase II of the park’s development has seen the restoration of the area’s wetlands, which absorb floodwaters, while revetments protect the wetlands themselves from the currents of the abutting East River. These revetments simultaneously act as a pedestrian pathway that runs atop the river barrier.

Behind this couple viewing the mixed-use field—part synthetic grass for sporting activities and part authentic grass for leisure use—you can see the bioswales lining the street. (Image courtesy of NYC Parks.)

Extreme Temperatures

In July 2018 alone, 41 different heat records have been broken in the United States. Dickson warns that this is just the beginning, with Arup studies projecting that, “by 2070, Boston’s entire summer could be an extended heat wave,” with daily temperatures extending beyond 90°F.

“This has significant impact obviously not only on cooling demands and how well our HVAC systems may or may not work, but it also has significant public safety and public health implications,” Dickson said.“We work a lot in the health-care sector, and one of the things that they’re trying to understand is not only what it means for their facilities but also patient surge. It has implications even for the labor force—how much people can or cannot work outside. It has significance for whether or not people are willing to bike to work, whether they’re able to wait at a bus stop for public transit.”

Disproportionately affected by this extreme heat, and all of the effects of climate change, are the world’s poor, given their lack of resources to deal with these dangers. During the record-breaking temperatures of this summer, there have been documented cases of impoverished groups that have been unable to safely ride public transportation. The U.S. Occupational Safety and Health Administration has tied deaths this year to the record high temperatures, recognizing extreme heat as a threat to those who work outside, particularly in the construction and agriculture industries.

Dickson has performed work for one municipality with regard to extreme heat and its impact on the tourism industry. Recognizing this need, the city has been assessing the associated public health concerns and how the city could be made more comfortable and attractive in the midst of rising temperatures.

While extreme heat will increasingly be the norm in the long term, in the nearer term, there will be extreme cold snaps caused by a change in dynamics related to the polar vortex. Typically, a large temperature difference between the polar vortex and the polar jet stream contains the Arctic’s cold air to the North Pole. As Artic temperatures increase, however, they are able to escape to the mid-latitude regions of the planet, bringing cold air with them.

According to Dickson, it’s only been in the last couple of years that serious consideration with respect to engineering design has been taken to address these concerns. She says that this means that designing for resilience requires both extreme heat during the summer and extreme cold during the winter.

Financing and Policy

Though resiliency can often save money, in the event of a disaster, funding resilient design projects is not so easy, according to Dickson. The challenges are often rooted in how much resilience is valued and how funding is generated.

To achieve this, Arup’s Lisa Dickson believes that necessary changes must be made in terms of financing and policy. Though resiliency practices can ultimately save money over the lifespan of an asset or a system, most operators are still approaching disasters reactively, rather than proactively.

“If you look at the ROI in terms of preparing for extreme weather, it’s always positive. $1 invested in resilience can save $4 in disaster response recovery,” Dickson said, showing engineering.com a presentation given to Congress earlier this year. By introducing the concept of resilience early on in the planning process, clients may see that it represents a tiny portion of the total costs of a building project. In the case of Arup client Partners HealthCare, “Despite all those major resilience interventions that they put in, that extra cost was less than 0.5 percent of the overall construction cost,” she said.

On the insurance side, Dickson suggests that policies take a longer view of risk, considering the probability of natural disasters over 20, 30 or 50 years rather than annually, thus reflecting more realistically the lifespan of a typical infrastructure asset. Whereas there may be a 1 percent chance of flooding occurring during one year for a particular area, this actually translates to a 39 percent chance of flooding occurring over a 50-year time frame. Such a view may more accurately convey the value of resilience to builders, according to Dickson.

She also believes that many private investors can be similarly shortsighted, aiming for a three- to five-year return on investment—again failing to address any consideration of longer-term issues such as climate change.

To address these issues, Dickson believes governmental policies need to be enacted to spur government funding and private financing, potentially resulting in public-private partnerships for large infrastructure projects.

“We’re doing work with a large development bank to determine how they incorporate climate change into their procurement process as it relates to transportation,” Dickson said.“One of the things that we recommended is that they lean more heavily on availability payments and they do that over a 20- or 30-year period. That forces the contractor to consider what the climate risk might be in the next one to three decades, because if that’s not carefully considered in terms of the construction for that particular project, that means that roadway is going to be closed due to climate disruptions. It incentivizes that you only get availability payments if that roadway is open. That roadway is only going to stay open if you incorporate climate risks into your design.”

Climate Outlook

While resilience is seeing adoption for building and infrastructure, resilience for the planet and its inhabitants is difficult to foresee. Dickson’s formal academic background is in paleontology, specifically mass and background extinctions.

She believes that the ecosystem will undergo some combination of three different outcomes: elastic recovery, in which an environment returns to normal; plastic recovery, in which it recovers but is not the same as it was before climate change; and a brittle failure. This would take the form of either a local background extinction or global, mass extinction.

Right now, according to Dickson, humanity is testing its luck and not changing its behavior as quickly as it should. She says that we are currently heading toward a cliff in which there will be “less plastic deformation and more of a brittle break.” She asks the question of how much the system will have to break before the species changes its ways. Nevertheless, she is hopeful that it’s not too late.

To learn more about the relationship between climate change and the built environment, read our recent article on the topic. To learn more about Arup, visit the company website.