The Impact of Roads on Nature

The science of road ecology studies the influence of roads on nature. Their findings to date indicate that roads, even unpaved ones, impact the earth in every way and at every scale. But perhaps the most vexing is noise pollution, even more than roadkill, particulate pollution, and constraints on gene pools. Noise bleeds into its surroundings. Eighty percent of the United States lies within a kilometer of a road, a distance at which vehicles project 40 decibels. As traffic swelled in the 20th century, road noise became a public-health issue, depriving us of sleep, impairing our cognition, and producing the stress hormones that lead to high blood pressure.

Most people treat the words “sound” and “noise” synonymously, but they are antonyms to acousticians. Sounds are fundamentally natural and often barely perceptible. Noise, by contrast, is a human-produced pollutant. It is unpleasant. People with good hearing register sounds as low as 10 decibels. Most animals can detect sounds at negative-20 decibels. For most of them, vision is a luxury, but hearing a necessity for survival in the wild. For this reason, most wild creatures try to get as far away from roads as they can, which confounds their migration routes and their propensity to diversify their gene mix.

Ben Goldfarb, in his book Crossings, described research that was done a decade ago on a raised green mesa in central Idaho. This area was a major refueling stop for throngs of southbound migrating songbirds, probably selected in part because there were no roads nearby. The researchers wanted to observe how these travelers would respond to amplifiers placed in the area broadcasting traffic noise from dawn to dusk. On days when the recording was played, bird counts plummeted, some species avoiding the area altogether. They found those who did stop were skinnier because they had to devote more time scanning the skies for hawks, rather than eating berries and beetles while being alerted to danger by the alarm chirps of chipmunks or martens. For the first time, this research verified that noise alone could impinge on animals’ survival.

Some national forests’ rangers and administrators are starting to push for the removal of forest service roads, concluding that the best way to create quiet habitat for wildlife is to not have roads through wilderness areas.

As Goldfarb put it at the end of his book, we need “a solar panel on every roof, a wetland on every floodplain, a wildlife crossing at every migration corridor” to reverse our devastating impact on the natural world and become a more benign presence. He continues, “And our investment in crossings must be matched by our commitment to habitat preservation: an overpass whose surroundings get developed into strip malls and condos is just an expensive bridge to nowhere.”

Congress’s recent infrastructure bill allocates $350 million for wildlife crossings and road-ecology interventions, the largest investment ever in road removal and animal-friendly infrastructure. 

Transforming Concrete from a Carbon Emitter to a Carbon Sink

Carbon-Negative Concrete Will Be a Game-Changer for the Building Industry

There are only a few countries that are carbon-negative, and they are all small. Only one has been officially certified, and that is the Kingdom of Bhutan. It offsets four times as much carbon as its economy emits.

Most materials have a positive carbon footprint, meaning that the harvesting, extraction, manufacture, and shipping related to them releases carbon, or in other words, that they contribute to the climate crisis. Steel, concrete, and aluminum are among the worst offenders.

The building sector has been a major contributor to carbon emissions. Cement, the binder component of concrete, accounts for 8 percent of global carbon emissions, or 25 percent of all industrial emissions. One ton of cement emits almost a ton (0.9) of carbon. If we could populate an imaginary country with all the cement manufactured every year, it would be the third largest carbon-emitting country, trailing only the U.S. and China.

Universities and private companies are researching ways to reduce concrete’s carbon impact. One company, Partanna Global, has developed a concrete that minimizes CO2 emissions during manufacture while offsetting these few emissions by absorbing carbon from the atmosphere during the curing process. According to the company, it is as versatile and affordable as traditional concrete, and in addition, it is stronger and more durable.

Of course, the company does not reveal its proprietary formulas, but does say it uses steel slag, a biproduct when iron ore is turned into steel. It also uses desalination waste, a chemical left behind when brine or saline water is made potable. This alkaline, calcium-laced water saturates the slag during formulation, creating reactive compounds that absorb CO2 into the concrete mix to become the binding agent. Moreover, these reactive compounds continue absorbing carbon from the air throughout the life of the concrete.

 Since cement, a key component of concrete, is ubiquitous in buildings, Partanna, by developing a carbon-negative concrete, has been able to easily take the next step and create carbon-negative homes. They have built their first negative homes in the Bahamas and have secured an agreement with the government to build 1,000 more. Each of these modest 1,250-square-foot homes will capture 182 tons of CO2 from the air, the equivalent to the annual carbon absorbed by more than 5,000 mature trees.

Another factor that helped convince the Bahamas to commit to these new homes is that the concrete gets stronger when exposed to seawater, whereas traditional concrete is weakened by this exposure. This makes it ideal for low-lying communities faced with the threat of sea rise and storm surges.

Carbon-negative concrete would shift the building industry from being one of the biggest contributors to climate change to helping heal the planet, while recycling waste products into the concrete. 

3D-Printed Houses

Speedily Built, Disaster Resilient, Energy and Resource Efficient, and Attractive

Big challenges face our society and our planet, none bigger or more pressing than climate change. A ray of hope is how innovative new technologies are tackling a number of these challenges simultaneously. In the housing sector, the 3D-printing process, without much publicity, is launching a revolution in construction materials and methods that are addressing affordability, energy-efficiency, durability, and beauty while erecting structures in record time and at scale.

The software, robotics, and new mixes of materials are technically complex but once the large printers, equipped with robotic arms that travel on rails, are set up, the process is simple. Nozzles at the ends of the robotic arms extrude environmentally friendly concrete mixes, plastics, hemp, mud, wood fibers, and other materials in a layering sequence to create solid, three-dimensional walls. Large sections of the building are printed and then assembled. Tech firms and architects are teaming up to produce designs that incorporate undulating curves that would be extremely time-consuming and prohibitively expensive to create using traditional building practices.

Jason Ballard, CEO of one of these pioneering tech firms, says, “With 3D printing, you not only have a continuous thermal envelope, high thermal mass, and near zero waste, but you also have speed, a much broader design palette, next-level resiliency, and the possibility of a quantum leap in affordability. This isn’t 10 percent better; it’s 10 times better.”

This type of construction is being employed in the Netherlands, Mexico, Canada, the U.S., and in areas impacted by natural or man-made disasters where quick rebuilding is urgent. These houses are built to withstand hurricanes and earthquakes. Entire communities are being designed and constructed; sometimes the printing is on-site and sometimes close by. Lennar Construction, one of the country’s largest builders, is building a 100-unit 3D-printed home development in Texas. Austin, Texas, has become a hub of robotic construction in this country. For example, it is turning out 400-square-foot homes to house 480 homeless people, or 40 percent of its street dwellers. The cost is $4,000 per unit. Printing time for an entire home varies between 24 hours and a week and a half, the longer period being for larger custom homes.  

Biophilic design, the recent term for increasing occupants’ connectivity to the natural world, is being embraced in most of these ventures. The mechanical nature of the production process may give the impression of uniformity and starkness, but the irregularities and imperfections of the striations have led some to compare the homes to adobe architecture. Similarly, the softer curves often harmonize with nature. Carefully thought-out, intricately designed print paths accommodate and hide high-performance mechanicals. 

The potential of 3D-printed housing embraces beauty, livability, economy, and resource efficiency while cutting construction time to a fraction of that required by traditional building methods. How quickly will it move to mainstream?

Impressions from a Month in France and Scotland

Climate and Resilience Issues Are Being Addressed in Impressive Ways

This summer’s heat extremes in Europe have set new temperature records, spread wildfires, and created public health issues. Fifteen thousand people died in France during the August 2003 heat wave. This summer, with even higher temperatures, no one has died in France. Big numbers have died in other southern European countries where there have not been the same kind of measures taken to protect citizens. The French government has created a comprehensive heat emergency plan as part of a larger scheme to address climate change and boost climate resilience. 

Swimming pools, bathhouses (dating back to the period before many French had bathrooms at home), and parks are open daily and with hours extending to almost midnight. Misting machines in parks, plazas, and other public spaces, often tied to fire hydrants, are set up to cool these areas and create fun places for children to play. “Heat wave kits” are sent to parents for their children and to older, at-risk people.

There is also a push to ban cars in French cities and make public transportation free during temperature spikes, but this has not turned into official policy yet.

The heat island effect makes French cities as much as 18 degrees Fahrenheit hotter than the rural hinterland. To counter this phenomenon, streets and sidewalks are being made more porous, thousands of urban trees are being planted, and roofs are being transformed into green, vegetated coverings. According to Le Parisien, a national newspaper, the temperature can differ 90 degrees F between an asphalt-topped roof and a green roof.

In Britain, railway engineers were painting iron train tracks white to reduce temperatures by 10-15 degrees F and minimize buckling. 

Circling back to climate change, Scotland set a target of 100 percent renewable electricity by 2020; they hit 97 percent. Wind generators contribute the major component of this renewable power, 66 percent of it from offshore wind farms. Although wind towers dot the Scottish countryside, careful siting prevents view corridors or protruding above ridgelines. Perhaps because of Scotland’s long history of civic involvement, the Scots have done better than the French in taking aesthetics into account when locating wind turbines. 

Scotland is finalizing a development formula by which local communities will get a percentage of the returns from wind generators and other renewables for education, health, and affordable housing budgets. One sees almost as many solar panels in Scotland as in Southern California, despite their far north latitude. Ocean current, tidal, and bio waste also factor into their clean energy mix