UPDATE (August 9, 2016): Momentum is continuing to build around AB 2800 in the California Legislature and among experts who design and build our critical infrastructure. Learn more.
Californians depend on a safe and robust infrastructure system to get what they need and where they need to go. It is critical to the state’s economy—the 7th largest in the world—and the safety and quality of life for all its residents. From roads and bridges to dams, reservoirs, and buildings, the state spends billions of dollars each year on infrastructure projects to preserve and enhance the system’s capacity to reliably provide these crucial services.
But climate change is affecting portions of our existing infrastructure, and is likely to have even greater impacts on new infrastructure. This is especially true for projects built to last past mid-century when climate projections become more severe.
These long-lived infrastructure projects should be built to withstand the impacts of a changing climate so they can remain functional, durable, and safe over their useful lives. The creation of a Climate-Safe Infrastructure Working Group (Assembly Bill 2800, Quirk, 2016) composed of engineers and climate scientists is a small but necessary step towards this goal.
Building for a “new normal”
As a result of climate change, the past is often no longer a good predictor of future conditions. In a report released last year, the American Society of Civil Engineers (ASCE) described how engineering practices must adapt in the face of a changing climate:
“Engineering practices and standards are typically based on assumed stationarity of extremes of climate and weather – that the frequencies and intensities of extremes observed in the past adequately represent those that will occur in the future. This assumption may not be valid under a changing climate.”
Instead, we can expect higher temperatures, more frequent and intense extreme weather events, and accelerated sea level rise in the future, as described in the state’s most recent climate assessment. Californians are already experiencing some of these impacts today, including rising sea levels, heat waves, flooding, and a record-breaking drought.
The way we design our infrastructure must reflect this “new normal” so that it can withstand these changing forces and stay durable, safe, and functional for many decades to come.
Disconnects between engineering and science threaten infrastructure safety and benefits
This shift will require better integration of climate science into engineering practices and standards. For example, Caltrans’ Highway Design Manual provides guidance to engineers on designing the state’s highway system. Section 818 acknowledges that “stationarity,” as described above, may no longer be a valid assumption when designing roads to withstand floods. Yet at the same time, it recommends a stationarity-based approach until there’s consensus on future trends.
Science overwhelmingly points to a future with more extreme weather events while climate models provide possible ranges for these changing conditions. They each come with varying degrees of uncertainty, particularly at the geographic scale used for infrastructure projects. (One of the biggest sources of uncertainty is the rate of heat-trapping emissions over the next century, which is directly influenced by our policy choices today.) This information, however, is not always available in a form that is readily usable for engineering purposes.
The stakes are high for getting this right. Take the new Bay Bridge, for example. The project began prior to the state’s requirement to consider sea level rise in construction project planning. According to a report by the Metropolitan Transportation Commission, the approach to the new Bay Bridge “will be permanently inundated by three feet of sea level rise,” resulting in costly transportation delays for 280,000 vehicles that traverse the bridge daily and millions of dollars for protective measures. It serves as a cautionary tale for the state’s major infrastructure investments.
It’s also not the only instance of infrastructure planning that has ignored climate science. Last year, my colleague profiled several other “climate-water” disconnects in a blog series on the topic.
Assembly Bill 2800: bridging the science-engineering gap
Fortunately, Governor Brown and the Legislature recognize the need to consider climate impacts in the state’s infrastructure planning and investments. State agencies and the Office of Planning and Research are undertaking important planning efforts in response. The state has also invested heavily in developing state-of-the-art models to project a variety of climate impacts and making this information publicly available.
What’s missing from these efforts is a two-way conversation between the climate scientists who produce this information and the engineers who design and oversee public infrastructure projects. Put simply, climate scientists need to engage engineers so they can provide them with practicable climate information. Engineers should also work closely with scientists to gain a better understanding of the underlying assumptions and caveats of the climate data. ASCE’s 2015 report underscores the importance of this collaborative effort for designing infrastructure to withstand the unavoidable impacts of a changing climate.
Assembly Bill 2800 (Quirk, 2016) fills this gap by establishing a Climate-Safe Infrastructure Working Group. The working group brings together engineers and climate scientists from key state agencies and research centers to identify best practices and recommendations for integrating climate science into engineering design practices for public infrastructure projects.
This critical conversation, and the information it will generate, represents a small but crucial step towards an infrastructure system capable of supporting our economy, public safety, and quality of life in the new climate future.
UPDATE (August 9, 2016): AB 2800 passed out of the California Assembly in June with a bipartisan vote and is now in the Senate, where it’s in the Appropriations Committee after passing the Natural Resources and Water Committee and the Environmental Quality Committee. It now includes licensed architects with relevant experience as members of the working group, in addition to engineers and climate scientists.
The bill enjoys a broad coalition of support, including the Professional Engineers in California Government and the American Institute of Architects (California Council), American Society of Civil Engineers (Region 9), Local Government Commission, Silicon Valley Leadership Group, Climate Resolve, and others. Recent federal actions, such as the White House Conference on Resilient Building Codes and the final guidance for considering climate change in NEPA, further underscore the need for an AB 2800-like dialogue about designing our infrastructure to withstand the impacts of climate change today and well into the future.
Featured Image: Bay Bridge 360/Flickr