11/08/2018
Transportation Infrastructure is a marvelous thing, isn’t it? Recently my family and I covered several hundred miles, linking the subtropics of Florida to the beautiful Fall colors of Northern Georgia. I love the American Road and the freedom that it provides. Amazing landscapes of all sorts can be seen in a single trip, and it’s possible to go almost coast to coast on a single road.
Infrastructure design incorporates all kinds of parameters. Possible loads and traffic volume, construction materials and their resilience, careful design that maximizes efficiently and safety within a certain budget. As part of this, the weather and climate conditions of an area are taken into account. Engineering uses certain standard climate variables in their determination of these other ingredients. For example, with bridge design, we want to know the typical range of hot and cold conditions, and how much the structure could expand/contract. For culverts and drainage, we want to know what peak flows can occur, and what the typical flood return period is, such as the 25, 50, or 100-year flood. In this process, there is a tacit understanding that the climate of the past is the climate we should expect going forward, and, for the most part, our infrastructure is designed under that assumption.
But what if that assumption is wrong?
If the climate of the future doesn’t look quite like the climate of the past, how then do we design? What should we expect over the next 20,30,50 years or more?
Let’s just be real. Climate change is a sticky subject. It has become tied up with political affiliation, and it is the sort of thing we don’t like to talk about. The climate changes naturally doesn’t it? Well, yes. However, over 98% of scientists globally agree that our fossil fuel-related activities are primarily responsible for this most recent set of changes being observed in our earth system.
Well, okay, but how can we possible know what might happen on the regional or local scale?
That’s a fair point. One of the limitations in planning for climate change expressed by many decision-makers is the issue of scale and uncertainty. We have general guidance on changes in weather extremes and climate, but regional and local information is less well understood. Fortunately, thanks to some novel modeling approaches, we are closing that gap. The issue of uncertainty is still large, and unfortunately we cannot see the future clearly, so perhaps our thinking needs to become less deterministic, and more probabilistic. Perhaps we need to think across a range of possibilities, and evaluate infrastructure design options across them. Are their any commonalities or cost-saving measures we can pull out whilst improving our preparedness for an increase in certain extreme events?
A few years ago, I was part of a small group in a limited study that attempted to do one simple thing. We wanted to create climate information that was a little more regionally and locally relevant to transportation concerns. We didn’t have the ability to do much more than that, but we wanted to start a conversation. We wanted to bring a compelling case forward for the need to consider future climate, and to do this, we focused on extremes. We also solicited expert input as to what those extremes of note were. Resulting from this, we analyzed a suite of recent high-resolution climate projections and historical data to examine local and regional trends across the 5 state region of Arkansas, Louisiana, New Mexico, Oklahoma, and Texas. This work was thanks to a grant from the Southern Plains Transportation Center (SPTC-105336600), and the University of Oklahoma (USO-122799700) working through the South Central Climate Adaptation Science Center
Our project has been output as a series of state ‘climate summaries’ that examine where we may be heading, and present some resources for transportation professionals to consider as they begin to tackle this large and complex subject. Those summaries are freely available, and you are encouraged to share them, and provide feedback. You can access them at: http://www.climateprojections.wixsite.com/transportation
Furthermore, various graphics are available for each Climate Division across these States.Those can be accessed via: https://data.southcentralclimate.org/SPTC_Climate_Projections_Data_and_Images under ‘Figures’. Data is still being archived to this site, and I’ll post an update when that is suitably complete. You have free use of both, only please remember to acknowledge Dr. Esther Mullens of the University of Florida & Dr. Renee McPherson of the South Central Climate Adaptation Science Center.
Travel safe y’all!