All posts by Tim De Chant

About Tim De Chant

Tim De Chant is creator of Per Square Mile and a contributor to The Atlantic Cities, Ars Technica, and Grist. He received his Ph.D. in Environmental Science, Policy and Management from the University of California, Berkeley. Tim's dissertation focused on the impact of urbanization on California's coastal oak woodlands. Follow him on Twitter and Google .

The Scientist Who Thought 22 Trillion Aliens Live in Our Solar System

Matt Simon, writing for Wired:

Here’s what Dick figured. At the time, there were an average of 280 people per square mile in England. And because he thought every surface of our universe bears life, it would naturally occur at roughly the same population density. So from comets and asteroids to the rings of Saturn, if you knew how big something was, you could guess how many beings live there. Thus, Jupiter would be the most populated object in the solar system, with 7 trillion beings. The least populated would be Vesta, the second largest asteroid in the asteroid belt, tallying just 64 million.

‘Year’s best satellite images’

It’s time for the usual end of the year lists, and Slate posted on on the “best” satellite images snapped by commercial outfit DigitalGlobe. Usually, when sites publish satellite photos, they’re cherry picked from terabytes of data. They look amazing because they’re sharp shots of charismatic places. This list is no different, except for one.

The second shot, the one of the Maidan in Kiev, Ukraine, shows what most satellite images look like. Far from crisp and stunning, it’s grainy, muddy, and riddled with obfuscating shadows. But it’s still amazing.

Summer jobs keep kids out of trouble

Emily Badger, writing for the Washington Post:

A couple of years ago, the city of Chicago started a summer jobs program for teenagers attending high schools in some of the city’s high-crime, low-income neighborhoods. The program was meant, of course, to connect students to work. But officials also hoped that it might curb the kinds of problems — like higher crime — that arise when there’s no work to be found.

Research on the program conducted by the University of Chicago Crime Lab and just published in the journal Science suggests that these summer jobs have actually had such an effect: Students who were randomly assigned to participate in the program had 43 percent fewer violent-crime arrests over 16 months, compared to students in a control group.

Turbolifts close to reality

Get ready, architects. German company Thyssenkrupp is close to testing a maglev-powered elevator that can travel sideways in addition to vertically. 

(James Temperton at Wired UK invokes the Wonkavator from Charlie and the Chocolate Factory, but I prefer Adam Rogers’s Star Wars/Star Trek reference—the turbolift.)

Hope for ash trees

Tina Casagrand, reporting for National Geographic News:

Kansas City plans to treat the roots of about 12,000 trees on city property, spending about $80 a tree for protection that lasts up to three years. Once taken up by the roots, the insecticide travels up the trunk under the bark—which is exactly where the beetle larvae do their damage, feeding on the wood and boring tunnels that interrupt the flow of water and nutrients through the tree.

Since the insecticide has to be reapplied every few years, it may not be economical as a permanent solution. But by preventing all the ash trees from dying at once, it would at least buy the city some time to replace its canopy and give its local partners time to create markets for beetle-killed ash products.

At a total cost of nearly $100 million for the city, even a one-time application of insecticide is a costly investment. “You have to look at the environmental, economic, and political benefits of a live tree,” Lapointe says. Tree-value calculators show that trees save millions of gallons of water from entering cities’ storm-water systems.

Years ago, the situation looked far more grim. Treatments cost hundreds of dollars per tree, which meant that cities didn’t even think about treating the trees. 

If there’s any good to come of this latest epidemic, it’s this:

In the void left by the vanished ashes, cities nationwide are planting more diverse species than ever before. Fort Wayne, for instance, has instituted a “Shading Our City” management plan that doesn’t allow more than 10 percent of any tree species to be planted in one area. Tinkel wants his city’s forest to be able to cope with future pests, blights, and climate change.

Prairies could make flying safer

Cara Giaimo, reporting for NOVA Next:

By turning hundreds of these acres back into prairie, Slaybaugh aims to mitigate the airport’s environmental impact. As part of a recent sustainability initiative, Dayton International Airport compared the potential carbon footprint of different land uses and found that rewilding would put them in the black: for every acre they switched from farmland to prairie grass, they would eliminate about 66 tons of greenhouse gas production. Add that to investments in alternative energy and green building materials, and Slaybaugh hopes the whole property will soon be “more sustainable and more resilient.”

This big new swath of prairie will provide homes for meadowlarks, bob-o-links, and other small songbirds that require at least 100 acres in order to nest successfully. It may also keep away other birds that threaten aircraft safety.

World’s largest tree planter wins award

A jury of architects and real estate investors awarded Bosco Verticale the “International Highrise Award”. The project, they say, is a “role model” for other densely populated areas. I respectfully disagree.

(Perhaps not coincidentally, the jury chair won the last installment of the prize for his high-rise in Sidney. It has a handful of trees on a roof deck, though they are heavily sheltered by tall panes of glass.)

(Via Lloyd Alter.)

A day in my life

Siri Carpenter interviewed me for The Open Notebook, a fantastic resource for journalists—professional and aspiring—that helps lift the veil on the craft. Head on over if you’re curious about what I do during a typical day.

New life for the artificial leaf?

Three years ago, the world was wowed by the advances in building artificial leaves—essentially solar cells that convert water and sunlight into energy. Reality fell short of the promise, but, as Phil McKenna reports for Ensia, there may be new hope for the promise. 

What happened to Google’s renewable energy moonshot?

Ross Koningstein and David Fork, two Google engineers, writing at IEEE Spectrum:

Google’s boldest energy move was an effort known as RE<C, which aimed to develop renewable energy sources that would generate electricity more cheaply than coal-fired power plants do. The company announced that Google would help promising technologies mature by investing in start-ups and conducting its own internal R&D. Its aspirational goal: to produce a gigawatt of renewable power more cheaply than a coal-fired plant could, and to achieve this in years, not decades.

Unfortunately, not every Google moon shot leaves Earth orbit. In 2011, the company decided that RE<C was not on track to meet its target and shut down the initiative. The two of us, who worked as engineers on the internal RE<C projects, were then forced to reexamine our assumptions.

At the start of RE<C, we had shared the attitude of many stalwart environmentalists: We felt that with steady improvements to today’s renewable energy technologies, our society could stave off catastrophic climate change. We now know that to be a false hope—but that doesn’t mean the planet is doomed.

Why Doesn’t Everyone Believe Humans Are Causing Climate Change?

Brad Balukjian, reporting for NOVA Next:

Only 40% of Americans attribute global warming to human activity, according to a recent Pew Research Center poll. This, despite decades of scientific evidence and the fact that Americans generally trust climate scientists.

That apparent cognitive dissonance has vexed two scientists in particular: Michael Ranney, a professor of education at the University of California, Berkeley, and Dan Kahan, a professor of law at Yale University. According to both, we haven’t been asking the right questions. But they disagree on what, exactly, those questions should be. If one or both of them are right, the shift in tone could transform our society’s debate over climate change.

China’s Island Factory

China is in the midst of a land boom. Not of the real estate kind, but the ocean-dredging, reef-filling, artificial island kind. It’s all part of the country’s push to establish a claim to vast portions of the South China Sea, and the BBC has a fantastically-detailed multimedia piece on the island building efforts.

The city is an ecosystem, pipes and all

Courtney Humphries, reporting for the Boston Globe:

As researchers delve into this world, they’re uncovering some surprises—like the unusual nitrogen cycles caused by homeowners raking up leaves in the fall, or the fast-growing urban trees. (BU ecologist Lucy Hutyra isn’t sure this is such a good thing: “Trees may be growing faster, but they could be dying faster,” she points out.) They are also, gingerly, suggesting that this gives us a new way to think about the future of cities. Living systems don’t just exist: They evolve, responding to changes in the rules that govern their existence. And as we try to design more sustainable cities for the future, understanding the full picture of urban ecosystems just might give us a smarter way to shape them.

While the study of urban ecology is old hat to regular PSM readers, Humphries’s piece is a great overview of the field, covering some genuinely interesting research.

Where Stuff Went Wrong for Missing Planes

My colleague Allison Eck and I assembled a map of the presumed locations of the accidents that led to the disappearance of the 28 passenger planes that have vanished since 1948.

Venice of the East Coast?

Casey Ross, reporting for the Boston Globe:

A report scheduled to be released Tuesday about preparing Boston for climate change suggests that building canals through the Back Bay neighborhood would help it withstand water levels that could rise as much as 7 feet by 2100. Some roads and public alleys, such as Clarendon Street, could be turned into narrow waterways, the report suggests, allowing the neighborhood to absorb the rising sea with clever engineering projects that double as public amenities.

The Musk Family Plan for Transforming the World’s Energy

Christopher Mims, writing at the Wall Street Journal about cousins Elon Musk, CEO of Tesla, and Lyndon Rive, CEO of SolarCity:

Mr. Musk’s Tesla makes cars, but it also—in the not too distant future—will make batteries. Lots of them. Tesla is building a $5 billion “gigafactory” in Nevada for batteries. A factory so large that it will, says Mr. Musk, be larger than the whole of Earth’s current capacity for manufacturing lithium-ion batteries. Most such batteries currently go into phones, tablets, laptops and other mobile devices.

At the conference Wednesday, Mr. Musk disclosed that a portion of the gigafactory’s capacity will be set aside for building “grid-scale storage.”

In other words, Tesla is going to continue its tradition of manufacturing battery packs for SolarCity, only on a much grander scale.

World population could hit 11 billion

After years of everyone growing comfortable with a global population of 9.5 billion, a new study claims we’ll fly right past that. Damian Carrington, reporting for the Guardian:

The work overturns 20 years of consensus that global population, and the stresses it brings, will peak by 2050 at about 9bn people. “The previous projections said this problem was going to go away so it took the focus off the population issue,” said Prof Adrian Raftery, at the University of Washington, who led the international research team. “There is now a strong argument that population should return to the top of the international agenda. Population is the driver of just about everything else and rapid population growth can exacerbate all kinds of challenges.” Lack of healthcare, poverty, pollution and rising unrest and crime are all problems linked to booming populations, he said.

So what changed? Our assumptions about the rate of population growth in Africa. Fertility rates there fell in the 1980s, but the trend hasn’t continued as many expected. And, more darkly, HIV/AIDS hasn’t claimed as many lives there as once projected. Combined, sub-Saharan Africa will hit 5 billion, according to this new study.

But the situation could change dramatically if education and access to contraceptives improves. (Women who attain higher levels of education tend to have fewer children; contraceptives, well, the effect is obvious.) If couples had on average 0.5 fewer children, the world population could drop to 6 billion, a number last seen in 1999. But 0.5 more per couple and it could spike to over 16 billion.