from the world's big
We may have to abandon concrete to fight climate change, architectural experts say
The building material seems so ubiquitous — what can we use in its place?
- Concrete is a surprisingly dangerous contributor of greenhouse gas emissions.
- For years, architects haven't been concerned with these emissions since concrete buildings last for so long; their carbon footprint is spread out over their entire lifespan.
- However, as we approach climate "tipping points," the front-loaded cost of concrete construction may be too high.
"If we invented concrete today, nobody would think it was a good idea," said architectural engineer and panel member Michael Ramage. "We've got this liquid and you need special trucks, and it takes two weeks to get hard. And it doesn't even work if you don't put steel in it."
The four billion tons of concrete produced for construction each year accounts for 8 percent of the world's carbon dioxide emissions, mainly through the production of clinker. Clinker serves as a crucial binding element in cement, the primary ingredient of concrete, and is produced by heating limestone and clay to around 1,400°C (about 2,500°F). Heating limestone (CaCO3) to these temperatures, however, causes a chemical reaction called calcination that results in lime (CaO) and carbon dioxide (CO2) as a waste product. Roughly half of concrete's carbon dioxide emissions is due to calcination, while another 40 percent comes from burning fossil fuels to heat up limestone to the point where this chemical reaction can occur. The last 10 percent comes from the fuel used in the mining and transportation process.
Eight percent might seem like a large slice of the world's carbon dioxide pie, but architectural experts haven't been particularly concerned about this figure until recently. The reason why has to do with concrete's longevity. Normally when calculating a building's total carbon emissions, said Phineas Harper of Dezeen magazine, architects take the amount of carbon needed to construct a building and divide it over the building's total lifespan. "That gives you your per-year carbon emissions," said Harper. However, in our current climate situation, this kind of thinking is "dead wrong."
Had we taken climate change more seriously a hundred years ago, this would probably be fine. But as it stands today, we have only a few short years before we reach climate "tipping points," events that create negative feedback loops in the climate that are very difficult to reverse. The melting of polar ice, which reflects sunlight and contains locked-away greenhouse gases, is a well-known example of such a tipping point. So too is deforestation in rainforests, which increases the likelihood of local droughts, killing even more trees.
As a result, the front-heavy carbon load of concrete buildings inadvertently contribute more to climate change than any straightforward calculation may suggest.
Looking for alternatives
So, if we can't build sustainably with concrete, what other materials can we build with? Ken de Cooman, founder of BC Architects & Studies, discussed how his firm is using materials primarily formed from the earth, like compressed-earth bricks. There are also biocomposite materials, which are formed out of natural fibers embedded in a matrix. Hempcrete, for instance, is a biocomposite of hemp and lime that is actually carbon negative since hemp absorbs CO2 as it grows.
Interestingly, one of the best candidates for replacing concrete in construction projects is something of an old-fashioned solution — timber. One might wonder if using timber is all that wise given the importance of forests in maintaining the health of our environment, this might seem counterintuitive. Ramage acknowledged that building out of timber would require sustainable practices. In order to make construction using timber sustainable, a number of trees would have to be planted for every tree that is cut down. And, added Ramage,"It's important to remember that every kilogram of timber we build with holds the equivalent of 1.8 kilograms of carbon dioxide." Unlike concrete, timber stores carbon dioxide, lowering a building's overall carbon footprint.
A photo of Andrew Waugh's all-timber building constructed in North London.
Image source: Architecture of Emergency, 2019
As an example of this, architect Andrew Waugh described a building his firm built in North London.
"We built the entire building from solid timber from the first floor up. So all the internal walls, external walls, lift shafts, staircases, all in timber. … It's about 2.8 trees per person that live in that building and for every one of those trees that was cut down to build that building five more were planted in its place."
Timber is growing in popularity as a construction material, both because of its greater sustainability and because of advances that have enabled it to be used in taller buildings, like cross-laminated timber. These developments have not left the concrete industry too happy, which has taken out advertisements emphasizing the flammability of timber buildings and the environmental impacts of cutting down trees.
"We must be doing something right," said Waugh, "because, much like the tobacco industry in the 1980s and 1990s, Big Concrete is beginning to fight back."
Many of the methods we can employ to address climate change can seem radical. After all, many climate change activists ask that we stop engaging in many activities that have been a part of our lives for decades. But the climate crisis didn't suddenly arise out of nowhere — it's these activities that have, bit by bit, added momentum to this phenomenon.
Reversing that momentum will mean cutting back on fossil fuels, eating meat, building in concrete, and many more activities that we have taken for granted.
Update Tuesday, October 15, 2019: This story was updated to specify when and how carbon emissions are released during the cement production process.
Ever since we've had the technology, we've looked to the stars in search of alien life. It's assumed that we're looking because we want to find other life in the universe, but what if we're looking to make sure there isn't any?
Here's an equation, and a rather distressing one at that: N = R* × fP × ne × f1 × fi × fc × L. It's the Drake equation, and it describes the number of alien civilizations in our galaxy with whom we might be able to communicate. Its terms correspond to values such as the fraction of stars with planets, the fraction of planets on which life could emerge, the fraction of planets that can support intelligent life, and so on. Using conservative estimates, the minimum result of this equation is 20. There ought to be 20 intelligent alien civilizations in the Milky Way that we can contact and who can contact us. But there aren't any.
Building a personal connection with students can counteract some negative side effects of remote learning.
- Not being able to engage with students in-person due to the pandemic has presented several new challenges for educators, both technical and social. Digital tools have changed the way we all think about learning, but George Couros argues that more needs to be done to make up for what has been lost during "emergency remote teaching."
- One interesting way he has seen to bridge that gap and strengthen teacher-student and student-student relationships is through an event called Identity Day. Giving students the opportunity to share something they are passionate about makes them feel more connected and gets them involved in their education.
- "My hope is that we take these skills and these abilities we're developing through this process and we actually become so much better for our kids when we get back to our face-to-face setting," Couros says. He adds that while no one can predict the future, we can all do our part to adapt to it.
Frequent shopping for single items adds to our carbon footprint.
- A new study shows e-commerce sites like Amazon leave larger greenhouse gas footprints than retail stores.
- Ordering online from retail stores has an even smaller footprint than going to the store yourself.
- Greening efforts by major e-commerce sites won't curb wasteful consumer habits. Consolidating online orders can make a difference.
A pile of recycled cardboard sits on the ground at Recology's Recycle Central on January 4, 2018 in San Francisco, California.
Photo by Justin Sullivan/Getty Images<p>A large part of the reason is speed. In a competitive market, pure players use the equation, <em>speed + convenience</em>, to drive adoption. This is especially relevant to the "last mile" GHG footprint: the distance between the distribution center and the consumer.</p><p>Interestingly, the smallest GHG footprint occurs when you order directly from a physical store—even smaller than going there yourself. Pure players, such as Amazon, are the greatest offenders. Variables like geographic location matter; the team looked at shopping in the UK, the US, China, and the Netherlands. </p><p>Sadegh Shahmohammadi, a PhD student at the Netherlands' Radboud University and corresponding author of the paper, <a href="https://www.cnn.com/2020/02/26/tech/greenhouse-gas-emissions-retail/index.html" target="_blank">says</a> the above "pattern holds true in countries where people mostly drive. It really depends on the country and consumer behavior there."</p><p>The researchers write that this year-and-a-half long study pushes back on previous research that claims online shopping to be better in terms of GHG footprints.</p><p style="margin-left: 20px;">"They have, however, compared the GHG emissions per shopping event and did not consider the link between the retail channels and the basket size, which leads to a different conclusion than that of the current study."</p><p>Online retail is where convenience trumps environment: people tend to order one item at a time when shopping on pure player sites, whereas they stock up on multiple items when visiting a store. Consumers will sometimes order a number of separate items over the course of a week rather than making one trip to purchase everything they need. </p><p>While greening efforts by online retailers are important, until a shift in consumer attitude changes, the current carbon footprint will be a hard obstacle to overcome. Amazon is trying to have it both ways—carbon-free and convenience addicted—and the math isn't adding up. If you need to order things, do it online, but try to consolidate your purchases as much as possible.</p><p>--</p><p><em>Stay in touch with Derek on <a href="http://www.twitter.com/derekberes" target="_blank">Twitter</a>, <a href="https://www.facebook.com/DerekBeresdotcom" target="_blank">Facebook</a> and <a href="https://derekberes.substack.com/" target="_blank">Substack</a>. His next book is</em> "<em>Hero's Dose: The Case For Psychedelics in Ritual and Therapy."</em></p>
Chronic irregular sleep in children was associated with psychotic experiences in adolescence, according to a recent study out of the University of Birmingham's School of Psychology.