Resilient infrastructure solutions for climate change
The IPCC has warned the public time and again that the world is heading towards a warming climate with rising oceans. Current projections are between 2-4 °C provided that positive feedback loops do not lead towards uncontrollable warming. Russian scientists are exploring the phenomenon of methane clathrates, a scenario in which methane locked in frozen solids begins to melt or bubble up to the surface, releasing tons of methane gas, a much more potent greenhouse gas than carbon dioxide. In fact a growing number of civil engineers around the world are taking the predicament seriously. Countless aging levees, bridges, highways, buildings, and public utilities are under siege due to weathering and inadequate maintenance, not to mention failure related to flooding, high winds, and fires.
Not only are scientists and researchers tasked with exploring the range of possibilities with respect to climate change, but civil engineers are tasked with preparing nations for a world with much more intense hurricanes, longer hot seasons, and rising sea levels. The American Society of Civil Engineers (ASCE) working with the Committee on Adaptation to a Changing Climate (CACC) is focused on developing new advisories for adapting a variety of infrastructure systems to the scope of climate change hazards. In 2018, the CACC peer reviewed and published Climate-Resilient Infrastructure: Adaptive Design and Risk Management, a book edited by Bilal M. Ayyub, Ph.D., P.E. including peer-reviewed papers and presentations around the country. This was partially based on previous policy developments, such as Adapting Infrastructure and Civil Engineering to a Changing Climate, white papers that were peer reviewed and published in 2015 as a book, with J. Rolf Olsen, Ph.D. as editor.
Adaptive Design needed in creating Climate-Resilient Infrastructure
Climate-Resilient Infrastructure: Adaptive Design and Risk Management
Committee on Adaptation to a Changing Climate; edited by Bilal M. Ayyub, Ph.D., P.E.
According to the back-cover:
“Climate-Resilient Infrastructure: Adaptive Design and Risk Management, Manual of Practice No. 140, provides guidance for and contributes to the developing or enhancing of methods of infrastructure analysis and design in a world in which risk profiles are changing and can be projected with various degrees of uncertainty requiring a new design philosophy to meet this challenge.”
This is a radical departure from the days of generally formulaic approaches applied to designing roads, sewers, building structures, and earthen dams.
Only 50 years ago engineers relied on more formulaic methods because they lacked the sophisticated technology of today. In the 1960s engineers and scientists used tools such as slide rules, abacus, trigonometric tables, and logarithmic graphing paper. In contrast today the world’s most complex analysis may be completed by sophisticated computer algorithms developed to model and map greenhouse gases, temperature changes, and sea level rise. In civil engineering, precision modeling is used to plan and design transportation systems, predict hydraulic flows, and analyze structural connections from variable loading conditions.
While it’s possible to design against the perfect storm catastrophe, civil engineers are limited by economic costs. How much is the public or owner willing to pay when deciding upon the trade-offs between an adaptive engineering design or limited failure? Project civil engineers increasingly manage additional responsibilities in evaluating all sorts of potential hazards but the design codes and guidelines used are dependent upon location, criticality of the hazard, and societal perceptions of that criticality. It may take decades for codes and standards to become accepted practice. Dr. Ayyub and his colleagues soberly acknowledge that in an age of melting permafrost, emergency guidelines may have to be developed even before the methodology is fully-implementable or the robustness of the design proven to withstand certain levels of catastrophe.
The risks of failure, types of solutions for recovery during climate change events, foresight in designing renovation for add-ons, and monitoring of “unknown unknowns” are explored in the risk analysis portions of Climate-Resilient Infrastructures, and Adapting Infrastructure, manuals of practice referenced above. Today’s engineers and architects are increasingly aware of the importance for supporting a perspective appreciative of sustainability and adaptability while improving, designing, or building all kinds of structures. At meetings and conferences, civil engineers are grappling with how to translate legalities in the global risk landscape as perceived by scientists and others into the useful theoretical framework accepted by designers for improving infrastructure safety and stability.
Every year, new themes and concepts are being adopted by CACC to convert into meaningful policy so it can be translated and included in manuals of practice and updating national building codes. Here are four key concepts the reader is introduced to in Dr. Ayyub’s, and Dr. J. Rolf Olsen’s books indicating the connections to global climate projections:
1. Extreme weather events increase with climate change
The key foundational concept is that climate change is here to stay. Even skeptics agree that to recoup their costs in investments and attract market rate buyers it makes sense to convey a sense of appreciation for sustainability while ensuring that what they build exceeds minimal design standards. Current codes require updating to account for level 5 hurricane wind gusts. Minimal heights for piers need to be raised as the sea level gradually rises. Snow loads are increased or traded off with the additional design loads from installing rooftop gardens.
These are basic examples of how architects and engineers will design for climate change in an environment where the unexpected is expected to become increasingly more commonplace. The challenges are how to prepare for stressful disruptions at a time when for over the past two decades Americans have been investing only half of what is needed for national upkeep.
“Deficient bridges, congested highways, outdated transit systems, an unreliable electric grid and leaky water pipes cost the average American family $9 a day.” (Source: ASCE Infrastructure 2017 Report Card)
The report card is issued separately from the growing urgency to prepare infrastructure for 21st century global climate change meaning that adequate preparation in infrastructure can easily top one trillion per year. This brings us to another key concept in Climate-Resilient Infrastructure, and Adapting Infrastructure which is that of designing for resiliency.
2. Manage risks through sustainable policy and resiliency
The average home-owner won’t recognize the extent to which his groundwater has been polluted by saltwater intrusion until it is possibly to late. The aborigines in Alaska cling to their homelands even when living off the land and seas is no longer that viable, and Alaskan roads liquefy due to melting permafrost. Similarly, many California foothills residents like to remain put until they are smoked out and tragedy happens, such as during the Camp Fire of 2018.
Civil engineers have long planned cities to last for centuries and to withstand wars, plague, population explosion, and more. Thus, it’s natural for them to care about building structures that last at least a hundred years. This is what might be termed resilience from the historical building registry but is a key concept in ensuring resilient performing infrastructure for the future especially with regard to the as yet unknown synergistic effects of climate change (as described amply in Climageddon by JobOneforHumanity.org)
Civil engineers can readily develop system resiliency if they anticipate viable alternatives before failure or disruption happens. Unexpected problems for transportation systems including pavement and track deformation, increased bridge scour and erosion from more frequent floods, increased traffic from sudden population growth, and accelerated corrosion of metal structures. If not anticipated, the result is shorter structural life expectancy, or failure culminating in loss of life or long delays while awaiting repairs.
3. Adaptive design to complement traditional reliable processes
One concept which is challenging to come to terms with for planners and designers is the concept that stationarity is dead. To facilitate regularity, civil designers traditionally use established design storm curves to size storm sewers more quickly and efficiently. However super-sized storm cells hovering for days require adaptations that will make the design process more iterative. Building in variability, negotiating economic risks, and utilizing decisions trees are topics for discussion in the manuals.
For instance, addressing how to prevent forest fires is a thorny topic in the media spotlight. Of course downed power lines are part of a monitoring program that may have been poorly administered, but there are far too many factors that play in from dry weather whether from homeless encampments, littering (anything from grass to cigarette lighters), overgrown brush, and of course transmission lines as part of a monitoring program that may have lacked adequate administration.
Under climate change, there is only so much that can be done to prevent forest fires, let alone fight them. What becomes paramount are ethical goals such as how to safely evacuate entire populations. According to Frontline “Fire in Paradise” there were many basic failures fueling the tragedy of Camp Fire which burned down the town of Paradise in 2018. Firstly, the emergency communications systems were confused, garbled, and inadequate. Secondly, the town evacuation plan was grossly inadequate. According to Jim Broshears, Paradise Emergency Operations Coordinator, the town didn’t have a plan to evacuate the entire town because it would have been ‘impossible.’ Due to high winds, firestorm flames were blowing sideways, and “that was what allowed it to throw fireballs all over our town.” Town leaders nevertheless maintain they did their best and that it was a success considering the challenges.
However the idea that there could be no plan to evacuate the entire town because “it wouldn’t work” is entirely counter-intuitive to the purposes of transportation planning. Whether the deaths of 85 civilians and the destruction of 18,804 buildings is a profitable exchange is a matter for future speculation.
YouTube commentator Mike shared an idea:
“I hope in the future when towns plan for a full evacuation due to a wild fire, they actually put the money together to widen their roads if needed.”
According to Fire Chief Messina (45min):
“The issue wasn’t how fast we notify the public but how fast we could get them off the hill. The transportation system could only hold so many vehicles and we were trying to put more vehicles on there than it could hold.”
Obviously an adaptive solution, outside the town fire code on what is defensible, is to make transportation re-designation of through lanes, upgrading of routes, and creating debris-free clearance zones a priority. However what makes a design feasible may need to be negotiated with new town visions, such as a town with a much smaller population living mostly around an airbase.
4. Dealing with “unknown unknowns”
An interesting presentation by Richard Wright, Vice Chair of the ASCE Committee on Adaptation to Climate Change, emphasizes the role and responsibility of civil engineers traditionally and in a changing world. Sustainable engineering practices mean working within limited constraints in order to prevent undue degradation of “the quantity, quality, or availability of natural, economic and social resources.” For instance, Wright recommends:
“Engineers should use low-regret, adaptive strategies, such as the Observational Method to make projects resilient to future climate and weather extremes.”
The need for versatility in training and approaches is symbolized by the complex challenges, the “unknown unknowns,” populations will face in the future. Ayyub, Olsen, and others emphasize the need to both learn about and explore climate change from a scientific perspective, and incorporate more observational methods of approach in developing low-regret whole life-cycle design. Their perspective correlates with that of the World Economic Forum’s Global Risk Survey (GRS) which charts as maximally likely and costly disruptions stemming from climate change, energy price volatility, and global governance failure. Crises stemming from water insecurity, storms & cyclones, and flooding are also likely from their point locations on the chart.
In this context, the role of engineers is more significant than previously ascribed when compared with less likely risks such as those for weapons of mass destruction, online data & information security, or space security.
However the grand takeaway in the climate dilemma according to the ASCE Climate Change task force is that to account for the future climate and weather dilemma, civil engineers should accommodate a range of future climate projections by estimating future climate extremes appropriately. By negotiating a feasible design and meeting the project requirement from owners, this will lessen the risks from all kinds of losses and failures that had been adequately anticipated, analyzed, and addressed, including liability concerns.
Wright recommends with regard to engineering research and practice:
“Engineers should engage in cooperative research, involving climate, weather, life and social scientists, to gain an adequate, probabilistic understanding of the magnitudes and consequences of future extremes.”
These climate change and resilient infrastructure adaptation books offer meaningful concepts that help reposition civil engineers as cooperative planners and thinkers working with other specialists. For instance, the risk management sections incorporates top-down versus bottom-up approaches to climate change solutions. An observational bottom-up method may rely on a meta-study based on existing network data; whereas an observational top-down method would project and simplify resource data into a locally crafted best available technology.
The possibilities in naturally-based versus human-constructed solutions are endless, and this is why the authors emphasize the need to forge new partnerships, and engage in policy development and decision-making, such as through federal inter-agency task forces.
Review prepared by Christine H. Kroll, P.E.