Much attention has been paid to the likelihood of more drought, fires and floods as the planet warms, but the most significant impact on public infrastructure won't come from extreme weather events, Paul Chinowsky says.

It will be the the change in what constitutes normal weather in various regions — higher temperatures for more sustained periods of time, higher or lower average humidity and rainfall — that will most tax buildings, roads and bridges that were built for one set of conditions and now have to function in another.

"Road surfaces get weaker in heat," Chinowsky said. "Asphalt gets softer. As trucks and cars pass, you get a lot more potholes, more cracking. It won't be a one time event but a constant thing. That's the part we don't talk about, but that's the part that's going to have a huge economic impact."

Chinowsky is co-director of the Institute of Climate and Civil Systems and the Mortenson Professor of Sustainable Development in the University of Colorado's Department of Civil, Environmental and Architectural Engineering.

Over the last decade, he has developed sophisticated modeling tools to predict the impact of projected weather changes on infrastructure and make recommendations about changes property owners and governments can make in building materials and systems designs to ensure they won't face even more expensive repairs and failures 10 or 20 years down the line.

Chinowsky and his students in the Climate and Civil Systems Lab at CU developed the first version of the model when he was approached by alarmed officials in Alaska. The state was doing an extensive analysis of the impact of climate change on its infrastructure, and their models showed the state would be having to rebuild roads every 18 months in 30 or 40 years.

Chinowsky realized there was a gap he could fill. Many people were working on the science of climate change, and many people were making more generalized predictions, but no one was doing the quantitative work that would help governments prepare for the coming changes.

The model started with the most important "stressors" on infrastructure — temperature, precipitation, humidity and flooding — and how materials and systems function in various conditions. Over time, the model grew in complexity.

Chinowsky was able to make recommendations to Alaska about road-building that would preserve more reasonable maintenance schedules as well as make recommendations about coastal roads that should be moved further inland.

Analysis being applied abroad and at home

Based on that work, Chinowsky's team was approached by the World Bank and the U.S. Environmental Protection Agency to do detailed analyses of the impact of climate change on roads, bridges and other infrastructure.

The World Bank has pledged $30 billion over a 25-year period to develop road infrastructure in Africa.

"That's a huge investment of member country money," Chinowsky said. "They want to make sure that investment is viable and doesn't have to be rebuilt right away."

Now Chinowsky is looking at infrastructure impacts locally. The results of the Colorado Vulnerability Project looking at building, road, bridge and rail impacts across the state will be released later this summer.

Chinowsky is also working with the city of Boulder. The East Boulder Recreation Center is slated for a major renovation sometime in the next several years, and the city wants to know what changes from current building standards it should incorporate into the rehabilitation effort to make sure the building doesn't need expensive repairs in just a few years.

Chinowsky is also looking at the maintenance schedule for the Boulder County Regional Fire Training Center near Boulder Reservoir.

European and many developing countries have been quicker to consider the impact of climate change and make adjustments now, Chinowsky said. The upfront cost is almost always higher, but much less expensive than repairing and rebuilding more often if infrastructure fails.

"We are making decisions right now that affect people 30 years from now," he said. "And if we do it at the lowest cost possible, we are mortgaging our future."

Colorado could become wetter and more humid

It's not just road surfaces that are at risk. If it rains more, roofs will develop more leaks in less time. If it's hotter and more humid, HVAC systems need to be more powerful and move more air.

Trains won't be able to carry as much freight because the weight will warp the rails at sustained temperatures above 95 degrees. The welds the connect sections of pipeline will also need to be redone more frequently.

Many Coloradans have heard that droughts and wildfires will get worse with global warming, but Chinowsky said many models show that over a longer period of time, it could become wetter and more humid here.

If bridges need to withstand occasional intense flooding, that calls for one approach. If rivers will be wider and carry more flow from a wetter climate, that calls for a different approach as the water puts constant pressure on bridge supports.

Most of the technology and engineering knowledge to support these changes already exists, Chinowsky said. Colorado just has to look to other parts of the country and the world to see what works there.

"I think a lot of people think we need to innovate our way out of this, and the reality is that we know what to do now and we can predict it now," he said.

Chinowsky said the United States has a historic opportunity now as much of the infrastructure that took the country into the modern era after World War II needs to be rebuilt.

"This is almost a once in a lifetime opportunity," he said. "If we miss this opportunity for another 50 years, the rest of the world is going to look at us and wonder why we didn't think weather and climate and sustainability were important."

©2014 the Daily Camera (Boulder, Colo.)