Three Tweets That Changed My Decade

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Public Domain. Blaise Pascal would have hated twitter/ Wikipedia

A look back at the tweets that changed the way I think about sustainable design.

Blaise Pascal once apologized for writing a long note: "If I Had More Time, I Would Have Written a Shorter Letter." (I know, this has been ascribed to everyone from Cicero to Mark Twain.) The character limit on Twitter has forced writers to edit their words and thoughts, and sometimes they can become quite profound and influential. There are three in particular that I have kept pinned on my bulletin board:

1. Jarrett Walker


Levittown/ New York Postcard Club/Public Domain A decade ago I quoted Alex Steffen from a timeless and wonderful article, My other car is a bright green city, with a section titled, "What We Build Dictates How We Get Around."

We know that density reduces driving. We know that we're capable of building really dense new neighborhoods and even of using good design, infill development and infrastructure investments to transform existing medium-low density neighborhoods into walkable compact communities. Creating communities dense enough to save those 85 million metric tons of tailpipe emissions is (politics aside) easy. It is within our power to go much farther: to build whole metropolitan regions where the vast majority of residents live in communities that eliminate the need for daily driving, and make it possible for many people to live without private cars altogether.
dedicated row

City of Toronto/Public Domain

I always thought that he had it backwards, that How we get around dictates what we build. I would look at the development 100 years ago of streetcar suburbs like the one I live in, shown above in 1913, and then auto-centric suburbs like Levittown. It is the transportation technology that determined what kind of place we lived in. My streetcar suburb was built with narrow lots because people had to walk up to 20 minutes to get to the streetcar.

Jarrett Walker Tweet

Jarrett Walker Tweet/Screen capture

It took transportation consultant Jarret Walker, who, when he is not fighting with Elon Musk, used just a few words to make it all clear: They are the same thing.

Emissions by sector

Emissions by sector/ Architecture 2030/CC BY 2.0

It's all the same thing. Making and operating buildings are 39 percent of our carbon emissions, and what is transportation? Driving between buildings. What is industry doing? Mostly building cars and transportation infrastructure. They are all the same thing in different languages, interconnected; you can't have one without the other. To build a sustainable society we have to think about them all together – the materials we use, what we build, where we build, and how we get between it all.

2. Elrond Burrell

The Elrond Standard

The Elrond Standard of Energy efficiency, embodied energy, health and walkability/Screen capture

When the Passivhaus or Passive House standard was created, the main driver was energy conservation. That was what people thought being eco was all about; they even wrote in the Passipedia:

Passive Houses are eco-friendly by definition: They use extremely little primary energy, leaving sufficient energy resources for all future generations without causing any environmental damage.

But we don't worry much anymore about leaving energy resources for future generations. Now we worry about leaving them in the ground so that we can leave a planet for future generations. I thought that a standard that just measured energy consumption wasn't good enough anymore. After a long discussion on Twitter about how we had to worry about the embodied energy, or upfront carbon emissions as I prefer to call them, and about the energy used getting between buildings, and about health, New Zealand architect Elrond Burrell summarized it:

Elrond Tweet

Tweet by Elrond Burrell/Screen capture

or: 1) Passive House energy efficiency + 2) low embodied energy + 3) non-toxic + 4) walkable.

I decided to call this the Elrond Standard. I concluded:

I think we do need a standard, particularly in the residential sector, that applies the rigor and math that Passive House applies to energy to these other factors of embodied energy, health and walkability. Perhaps it should be the Elrond Standard, since he inspired this. Because energy efficiency isn’t enough anymore.

After writing that, I did have second thoughts, particularly when we know that we have to cut our carbon emissions so dramatically to stay under 1.5 degrees; other considerations pale by comparison. Passivhaus may not be perfect, but it is the best way to achieve radical building efficiency right now, and carbon emissions generally still follow energy consumption. We really do have to start counting everything, the operating carbon emissions and the upfront carbon emissions, but we can build on what we have; Passivhaus doesn't currently measure carbon, but it's still the best place to start.

3. Taras Grescoe

CC BY 2.0. Lloyd Alter/ This needs fixing

Lloyd Alter/ This needs fixing/CC BY 2.0

Seven years ago, author Taras Grescoe tweeted a few words that I thought summarized everything that I had been saying about the future of the city:


Taras Grescoe/Screen capture

It is still, for me, the most important single answer to the questions about our future that I have seen, all in less than 140 characters. Since that tweet was sent we have seen the dramatic rise in the importance of the bicycle in our cities; the reintroduction of trams or light rail, and a massive investment in subways. I suspect if Taras was tweeting this today, he would have also included walking.

Meanwhile, the smart phone has changed our lives and is changing our cities, for better and for worse. It makes our 19th century tech easier and more pleasant to use, letting us know when a bus is coming and giving us lots to do while we ride, they let us find a bike or a scooter. Meanwhile, shopping apps are changing retail and may well be killing our malls.

Gentrification in Fishtown

Gentrification in Fishtown/ Lloyd Alter, 2012/CC BY 2.0

Inga Saffron just wrote in the Philadelphia Inquirer: How the smartphone explains Philly’s most profound urban design changes this decade. She notes the effect that the smart phone has had on the city: "The tech-induced trends from the last 10 years have challenged that physical form by radically reconfiguring the way we move through, and interact with, the city."

We know that once millennials (and their parents) got those smartphones in their hands, they promptly began moving into cities, buying fixer-uppers in working-class neighborhoods like Point Breeze and Fishtown, and transforming them into upscale enclaves. Facebook and Tinder made it easy for them to socialize, while app-driven services like Uber and Lyft, Peapod and Fresh Direct, ridesharing, and bikesharing allowed more people in greater Center City to ditch their personal cars (and more easily pay for their phones).

The tech companies feeding all this are engines of growth and change in cities all over the world, more proof that Taras Grescoe was right.

There are a lot of terrible things about Twitter. It takes up far too much of my time. But these three tweets aren't the only ones that I have found so interesting, influential, even profound. I look forward to the next ten years!