What do we mean when we say that a city is "healthy"? Do we mean that it's cleaner, safer and less polluted than others? That its economy is booming? That it spends its taxpayers' money wisely, on projects that benefit the many over the few? That it prioritizes the building of community, not just in the social but in the physical sense?
Jeff Speck believes that for a city to be described as healthy, it can't just be one, or even some, of these things; it has to be all of them. And he believes cities can achieve them by committing to the principles of walkability, the idea that communities should be built to meet the needs of pedestrians, not automobiles.
Speck, an architect by training, altered the course of our national conversation about urban planning six years ago with the publication of Walkable City. Pointed, funny and acerbic, his book railed against our sprawling automobile-focused culture and made the case for a human-scaled alternative.
To historically dry discussions of things like municipal parking policies, congestion pricing and traffic flow, Speck brought a fresh voice and a no-holds-barred attitude; reading him was a bit like reading Anthony Bourdain if the late food writer and TV host been more interested in sidewalk regulations than sidewalk cafes.

Walkable City became something of an evangelizing tool for advocates of smart growth and pedestrian-friendly communities, with adherents zealously handing out copies of the book to friends and acquaintances, "like tabs at a Grateful Dead concert," as Speck puts it (very Speckishly, I might add).
But while Walkable City may have been terrific at summarizing a new philosophy, it wasn't necessarily the best how-to guide for, say, swaying a city council member to narrow traffic lanes or persuading a mayor to install speed bumps or a new traffic circle.
Enter Speck's new book, Walkable City Rules: 101 Steps to Making Better Places (Island Press). Filled with the photos, graphics and charts that many of his fans felt were missing from the last book, the new volume comprises 101 mini-chapters, each of which elegantly distills a single precept from his philosophy over the course of just two pages.
If the first book was written to convince you, the reader who has already evinced a keen interest in urban planning, of the manifest benefits of walkability, the second book, in Speck's words is meant to help you convince other people.
Those benefits are walkability's demonstrably positive effects on a city's wealth, public health, equity goals, sense of community and, of course, climate change mitigation.
My conversation with Speck took place shortly after the UN Intergovernmental Panel on Climate Change released its much talked-about report detailing the consequences of allowing global temperatures to rise more than 1.5 degrees Celsius. Naturally, we discussed how investing in walkability can help cities lead the way in cutting greenhouse gas emissions. Speck had a lot to say.

If you count both first-order and second-order impacts, I think it's absolutely clear that the car-dependent lifestyle,,one that both is caused by and also causes sprawl, is the number one contributor to our destruction of the human habitat Speck told me.
The first-order impacts, of course, are all the emissions that come from driving, and the other pollutants that come from it, from the petroleum in our asphalt to the acid in our car batteries. But as my friend [New Yorker staff writer] David Owen has pointed out, the biggest contribution that driving makes to our environment is that it causes us to spread out. And when we spread out, we consume more land; we require more infrastructure per capita; there's more sewers and electrical lines per person. We consume just so much more.
Speck's new book can be thought of as a primer on how to free our cities from the tyranny of the automobile, moving them closer to their original identities as urban villages that foster community interaction by encouraging people to stroll sidewalks and linger in public spaces.
Among other things, it focuses on promoting dense, mixed-use development, ramping up bike infrastructure and right-sizing lanes (in both width and number) to lower traffic speeds and increase safety. And it makes clear that in this era of near-constant bumper-to-bumper traffic congestion, quick and dependable mass transit, and not cars, is what offers citizens the greatest amount of personal freedom.

Way back in 2000, Speck coauthored the seminal Suburban Nation: The Rise of Sprawl and the Decline of the American Dream, which laid the theoretical groundwork for a New Urbanist movement that championed density, walkability and shared public space as the bedrock elements of community. While it may not be accurate to say that the author has softened his stance on sprawl since then, it's probably fair to state that he has come to accept the fact of its continued existence, and would rather spend his time and energy these days on making suburbs and exurbs greener, smarter, and healthier than simply excoriating those who choose to live there.
Speck sees an example of what he deems training-wheel urbanism in the current vogue for open-air, mixed-use "lifestyle centers." These giant mixed-use developments, often found in exurbs, typically combine shopping, apartments, restaurants, cinemas, hotels and public parks or fountains, all designed to mimic the dynamism and vitality of a city streetscape.
The success of these projects outside Atlanta, Houston, Denver and other places signifies the public's deep desire, be it expressed or latent, to have the walkable-city experience even though they may be "surrounded by the miasma of sprawl," in Speck's words. And he's convinced that most suburbs built before World War II are sitting on economic gold mines in the form of abandoned Main Streets that are ripe for rediscovery and resuscitation along walkable, New Urbanist lines.
Speck and his firm keep quite busy these days consulting with cities large and small, studying traffic patterns, measuring sidewalk and lane widths, and helping city managers find new ways to incorporate walkability.
But he sounds sincere when he says that he hopes his new book will put him out of a job. I don't care if I never do another walkability study again he says. Not so long as lots of other people are doing them. I'd much rather be designing buildings!

Imagine being stuffed into a crowded train car and noticing a less crowded one just down the platform. You’d probably want to move over as soon as possible. Particles that follow this balancing act, known as osmosis spontaneously move from an area of high concentration to one of low concentration.
Now, scientists have used this tendency to create a power-producing membrane that can harvest electric current from nothing but salty water.
When ionic salts, made of bundles positively and negatively charged particles, dissolve in water, the bundles break apart, leaving positively and negatively charged particles free to participate in osmosis. By placing charged, thin membranes in between salty water and freshwater, scientists can create an expressway for the flowing particles, generating electric current. But these membranes are often expensive to manufacture and they tend to get leaky over time. That lets particles pass back through in the wrong direction, cutting into how much electricity they can produce.

Now, researchers have developed a new kind of gatekeeper, a “two-faced” membrane that has different properties on either side, from the size of the pores to the charge of the membrane itself. This encourages a steady flow of charged particles from one side to the other while preventing them from drifting back in the wrong direction. These so-called Janus membranes, named after the ancient Roman god of gates and passages, can also be manufactured to have different-size pores and hold different charges, allowing them to accept different kinds of particles.

The researchers tested their Janus membranes with salty sea water on one side and fresh river water on the other. They found the devices were able to convert 35.7% of the chemical energy stored in the salty water into usable electricity. That’s as efficient as most wind turbines and higher than most solar cells, they report today in Science Advances.
Next, the researchers plan to build larger membranes and see whether they can withstand the conditions of real sea and river water. If the membrane performs as well in “the wild,” the new membranes could be used to power remote communities with no other sources of renewable energy in just a few years, the researchers say. That suggests that when it comes to harvesting power from moving particles, being a little two-faced is a good thing.

Offering a stark warning that humanity may have even less time to drastically cut carbon emissions than the United Nations suggested in its latest alarming report on the climate crisis, new research published in the journal Nature on Wednesday shows that Earth's oceans have retained 60 percent more heat each year over the past 25 years than scientists previously believed.
We thought that we got away with not a lot of warming in both the ocean and the atmosphere for the amount of CO2 that we emitted. But we were wrong Laure Resplandy a geoscientist at Princeton University who led the new study, told the Washington Post.
The planet warmed more than we thought. It was hidden from us just because we didn't sample it right. But it was there. It was in the ocean already.
The U.N.'s Intergovernmental Panel on Climate Change argued in its report released earlier this month that humanity must cut carbon emissions in half by 2030 in order to avert climate catastrophe by 2040, but that timeframe was based on previous and possibly conservative estimates of global warming.
As the Post's Chris Mooney and Brady Dennis noted higher-than-expected amount of heat in the oceans means more heat is being retained within Earth's climate system each year, rather than escaping into space.

In essence they added more heat in the oceans signals that global warming is more advanced than scientists thought.
In a statement on Wednesday, Sierra Club executive director Michael Brune argued that the new research confirms that we have even less time to move beyond dirty fossil fuels like coal, oil, and fracked gas to an economy powered by 100 percent clean, renewable energy.
The world's oceans are the canaries in the coal mine when it comes to the climate crisis. The writing has been on the wall for years Brune said.
This global crisis demands nothing less than swift and meaningful action by every world leader to ensure a safe and healthy future for all. The Trump administration's continued ignorance and lack of action is wholly unacceptable, and together with our allies across the country, we will work toward a brighter, healthier, and safer future for all.

This one sounds a bit like a Jules Verne story. Researchers at the Chalmers University of Technology in Sweden claim carbon fiber can act as an electrode if small changes are made in how it is manufactured. Is that big news? Let’s look at what it could mean to the world of transportation.
Electric cars and trucks could be made of carbon fiber instead of steel or aluminum. That means they could be up to 50% lighter than equivalent vehicles today, which would dramatically boost their efficiency.
If their exterior panels are able to store electricity, those cars and trucks could use smaller, lighter, and cheaper batteries, or might need no battery at all in some cases. Lower battery costs would offset the higher cost of carbon fiber.
Airplanes account for a large percentage of carbon emissions from the transportation sector. The weight of batteries is a major stumbling block to the electrification of aircraft today. Carbon fiber that stores electricity might prove to be critical to the development of electric airplanes.

Leif Asp professor of material and computational mechanics at Chalmers, says A car body would then be not simply a load-bearing element, but also act as a battery he says. It will also be possible to use the carbon fiber for other purposes such as harvesting kinetic energy, for sensors or for conductors of both energy and data. If all these functions were part of a car or aircraft body, this could reduce the weight by up to 50 percent.
Not all carbon fiber is created equal, says Asp. Some has large, highly oriented crystals and is twice as strong as steel. That type of carbon fiber does not conduct electricity well. However, other types of carbon fiber have poorly oriented crystals. They are about as strong as steel but have good electrochemical properties. They also have the additional benefit of being less costly to manufacture.
We now know how multi-functional carbon fibers should be manufactured to attain a high energy storage capacity, while also ensuring sufficient stiffness Asp says. A slight reduction in stiffness is not a problem for many applications such as cars.
The researchers are exploring how to use the new technology with several automobile and aircraft manufacturers. For airplanes, the carbon fiber might need to be slightly thicker than it would be for automotive use to compensate for its decrease in rigidity, but making it thicker also increases its energy storage capacity.

The key is to optimize vehicles at system level, based on the weight, strength, stiffness and electrochemical properties. That is something of a new way of thinking for the automotive sector, which is more used to optimizing individual components. Structural batteries may perhaps not become as efficient as traditional batteries, but since they have a structural load bearing capability, very large gains can be made at system level Asp says. In addition, the lower energy density of structural batteries would make them safer than standard batteries, especially as they would also not contain any volatile substances.
If the whole idea of vehicles that are also batteries seems a little far fetched to you, remember that virtually all of the cockamamie ideas dreamed up by Jules Verne, nuclear powered submarines, sending people to the moon, became a reality eventually.
The idea of battery-powered cars was dismissed by many people as a joke ten years ago. We never know what the future might have in store. Structural batteries could play an important role in decarbonizing the transportation sector.

In the ongoing pursuit of abundant, renewable alternatives to fossil fuels, scientists have produced hydrogen for fuel cells through artificial photosynthesis, which splits water into hydrogen and oxygen. Traditional processes have struggled to use optical, electronic and chemical properties in a way that makes this method efficient, but now researchers from Berkeley Lab have created a recipe that could completely bypass the limitations in current materials.

The team has created an artificial photosynthesis device called a hybrid photoelectrochemical and voltaic (HPEV) cell that turns sunlight and water into two types of energy: hydrogen fuel and electricity. Existing artificial photosynthesis devices can only make use of small percentages of the sunlight that hits them.
As lead author of the study, Gideon Segev says It's like always running a car in first gear. This is energy that you could harvest, but because silicon isn't acting at its maximum power point, most of the excited electrons in the silicon have nowhere to go, so they lose their energy before they are utilized to do useful work.
The solution behind the new device, is to simply let those electrons out. The researchers added a second electrical contact to the back of the silicon component in the device, which splits the current produced by the sunlight's energy, and allowing some of the current to split the water in hydrogen and oxygen, and some to be captured as electricity.
Previous artificial photosynthesis devices have an efficiency of 6.8 percent. According to Segev, the new design has a combined efficiency of 20.2 percent.

Now the team has the basics down, it says it plans to continue improving the device as well as investigate real-world applications for it. Of course, the design does beg the question, why not just store the extra energy in a battery instead of making hydrogen? Batteries are expensive, is one answer, but fuel cells aren't cheap either.
Regardless, hydrogen is going to play a big role in the world's future energy mix, so any steps to improve the efficiency of its harvesting now is good news for later on.

A high-volume water generator that can create water out of precipitation, and can be used in any climate, has been awarded a $1.5 million XPrize.
The culmination of a two-year water extraction competition, the Skysource/Skywater Alliance was awarded for developing the machine that can produce, at minimum, 2,000 liters of water per day from the atmosphere using 100 percent renewable energy.
Like many innovations, the new machine steals from nature._ With the acronym *WEDEW (for Wood-to-Energy Deployed Water System), it creates its own clouds within a box the size of a shipping container. Powered by wood chips and similar biomass, the WEDEW draws warm air from outside and sends it through an antimicrobial air filter to remove impurities. Once inside the box, the WEDEW introduces the warm air to generated cold air inside. This produces condensation.
With few running parts, the machine can run for 10-15 years, according to its company website.

There's enough water within the atmosphere at any given time to fill the Great Lakes, around 3,100 cubic miles. Given the fact that this atmospheric water is constantly replenishing due to the planet's hydrologic cycle, the Venice Beach, California company has created a system that is unlikely at the current moment to effect the atmosphere negatively.
And on top of all that, keeping with the rules of the XPrize competition, it uses electricity efficiently at the cost of two cents per liter.
It’s a carbon-negative technology says David Hertz a California-based architect who helped lead the project, speaking to FastCompany. I think the future of technologies is going to be moving to this restorative, regenerative model that actually helps to repair the damage we’ve done.
Hertz envisions WEDEW systems as shock troops against water crises in the coming years.

Our process is one that is really antithetical to the slow-moving infrastructure that exists that is not able to be responsive to a changing climate as it is in the case of say, Cape Town, for instance he says, referencing the water concerns that have the South African city considering towing down an iceberg.
The global water crisis isn't solved yet. A Skywater Emergency Services Unit can produce 450 to over 900 gallons in a day. That's nothing to sneeze at, but it's worth keeping in mind that the average person uses 100 gallons a day.
But still, the technology is promising. And over a million dollars worth of prize money sounds like just the type of encouragement Skywater needs.

I'm guessing you are scoffing in disbelief at the very suggestion of this article, but bear with me.
A growing number of tech analysts are predicting that in less than 20 years we'll all have stopped owning cars, and, what's more, the internal combustion engine will have been consigned to the dustbin of history.
Yes, it's a big claim and you are right to be sceptical, but the argument that a unique convergence of new technology is poised to revolutionise personal transportation is more persuasive than you might think.
The central idea is pretty simple: Self-driving electric vehicles organised into an Uber-style network will be able to offer such cheap transport that you'll very quickly, we're talking perhaps a decade, decide you don't need a car any more.
And if you're thinking this timescale is wildly optimistic, just recall how rapidly cars replaced horses...
In 1908 the first Model T Ford rolled off the production line; by 1930 the equestrian age was, to all intents and purposes, over, and all thanks to the disruptive power of an earlier tech innovation, the internal combustion engine.
So how will this latest transportation revolution unfold?

The driverless Uber model
First off, consider how Uber and other networked taxi companies have already changed the way we move around. In most major cities an Uber driver, or one of its rivals, is usually just a couple of minutes away, and charges less than established taxis, let's say £10.
The company's exponential growth is evidence of how powerful the Uber business model is.
Now take out the driver. You've probably cut costs by at least 50%.
So if we're trying to work out when this revolution will begin in earnest the key date will be when self-driving vehicle technology is available and - crucially - has regulatory backing.
That could well be sooner than you think. The UK has said it hopes to authorise the first fully autonomous cars as early as 2021.
And, say enthusiasts for autonomy, it will only take one city to prove the technology is safe and useful and the rest of the world will very quickly rush to catch up.
So self-driving cars have cut our £10 journey to £5.

The switch to electric
Now imagine the current mostly fossil fuel-powered taxi fleet is replaced with electric cars.
At the moment electric vehicles are more expensive than similar models with internal combustion engines, but offer significantly lower lifetime costs.
They are more reliable, for a start. The typical electric car has around 20 moving parts compared to the 2,000 or so in an internal combustion engine.
As a result electric vehicles also tend to last much longer. Most electric car manufacturers expect their vehicles to keep on going for at least 500,000 miles.
These factors aren't that important for most consumers, after all, the average driver in England does less than 10,000 miles a year and our cars are parked 95% of the time. However, they are huge issues if you're using a vehicle pretty much continuously, as would be the case with a self-driving taxi.
Add in the low cost of recharging batteries compared to refuelling and you've got another dramatic reduction in costs.
And it's worth noting that the cost of electric vehicles is likely to continue to fall, and rapidly. As they become mainstream, returns to scale will drive down costs. That's the logic behind Tesla's $5bn (£3.8bn) battery plant, the so-called "Gigafactory".

How does this affect our £10 journey?
It brings another dramatic reduction. Fully autonomous electric taxi networks could offer rides at as little as 10% of current rates.
At least that's what tech prophet Tony Seba reckons. He and his team at the think-tank RethinkX have done more than anyone else to think through how this revolution might rip through the personal transportation market.
We've now cut our £10 fare to just £1.
Mr Seba calls the idea of a robo-taxi network "transport as a service", and estimates it could save the average American as much as $6,000 (£4,560) a year. That's the equivalent of a 10% pay rise.
And don't forget, when the revolution comes you won't be behind the wheel so now you'll be working or relaxing as you travel, another big benefit.
You still think that car parked outside your flat is worth having?
What's more, once this new model of getting around takes hold the benefits are likely to be reinforcing. The more vehicles in the network, the better the service offered to consumers; the more miles self-driving cars do, the more efficient and safer they'll get; the more electric vehicles manufactured, the cheaper each one will be.
Don't worry that rural areas will be left out. A vehicle could be parked in every village waiting for your order to come.
And range anxiety, the fear that you might run out of electricity, won't be a problem either. Should the battery run low the network will send a fully charged car to meet you so you can continue your journey.
You've probably seen headlines about accidents involving self-driving cars but the truth is they will be far safer than ones driven by you and me, they won't get regulatory approval if they are not. That means tens of thousands of lives, perhaps hundreds of thousands, will be saved as accident rates plummet.
That will generate yet another cost saving for our fleets of robo-taxis. The price of insurance will tumble, while at the same time those of us who insist on continuing to drive our own vehicles will face higher charges.

Human drivers banned
According to the tech visionaries it won't be long before the whole market tilts irreversibly away from car ownership and the trusty old internal combustion engine.
RethinkX, for example, reckons that within 10 years of self-driving cars getting regulatory approval 95% of passenger miles will be in these electric robo-taxis.
Will cars parked outside houses soon be a thing of the past?
The logical next step will be for human beings to be banned from driving cars at all because they pose such a risk to other road users.
Take a moment to think about the wide-reaching effects this revolution will have, aside from just changing how we get around. There will be downsides: millions of car industry workers and taxi drivers will be looking for new jobs, for a start.
But think of the hundreds of billions of dollars consumers will save, and which can now be spent elsewhere in the economy.
Meanwhile, the numbers of cars will plummet. RethinkX estimates that the number of vehicles on US roads will fall from nearly 250 million to just 45 million over a 10-year period. That will free up huge amounts of space in our towns and cities.
And, please take note: I haven't mentioned the enormous environmental benefits of converting the world's cars to electricity.
That's because the logic of this upheaval isn't driven by new rules on pollution or worries about global warming but by the most powerful incentive in any economy, cold hard cash.
That said, there's no question that a wholesale switch away from fossil fuels will slow climate change and massively reduce air pollution.
In short, let the revolution begin!
But seriously, I've deliberately put these arguments forcefully to prompt debate and we want to hear what you think.

The role of forests in combating climate change risks being overlooked by the world’s governments, according to a group of scientists that has warned halting deforestation is just as urgent as eliminating the use of fossil fuels.
Razing the world’s forests would release more than 3 trillion tons of carbon dioxide, more than the amount locked in identified global reserves of oil, coal and gas. By protecting and restoring forests, the world would achieve 18% of the emissions mitigation needed by 2030 to avoid runaway climate change, the group of 40 scientists, spanning five countries, said in a statement.
We must protect and maintain healthy forests to avoid dangerous climate change and to ensure the world’s forests continue to provide services critical for the well-being of the planet and ourselves the statement reads.

The intervention comes as the UN’s Intergovernmental Panel on Climate Change gathers in South Korea ahead of Monday’s release of an eagerly awaited report on how the world can avoid warming of 1.5C (2.7F) beyond pre-industrial levels, an aspirational target of the landmark Paris climate deal in 2015.
It is expected the report will focus on required changes to the energy system, rather than forests. In responding to the IPCC report, our message as scientists is simple: Our planet’s future climate is inextricably tied to the future of its forests the scientists’ statement pointedly concludes.
Trees and other vegetation currently absorb around a quarter of the CO2 humans are adding to the atmosphere, softening the potential impact of climate change.
While the world won’t lose all of its trees, large tracts of tropical forests, which hold a vast amount of carbon, are still being lost in the Amazon, central Africa and Indonesia. Warming temperatures are also fueling huge fires in forests in higher latitudes, as witnessed this summer when much of northern Sweden was aflame.
The forest piece of the conversation is often lost and I don’t think the IPCC report will highlight it enough said Deborah Lawrence a professor of environmental sciences at the University of Virginia and a signatory of the statement. We almost take forests as a given but we lose forest every year, which means we are diminishing them as a carbon sink.
Deforestation has been massively reduced in the Amazon, but that hasn’t happened elsewhere. As countries get more peaceful in Africa we could lose more tropical forests, which really worries me.

The IPCC’s report is expected to mention the need for as-yet unproven technology to burn vegetation and bury the resulting emissions underground or directly suck carbon from the air as a way to meet the 1.5C target.
The statement by Lawrence and other scientists warns the former strategy, known as bioenergy with carbon capture and storage (Beccs), is untested and risks wiping out huge areas of rainforest in order to make way for plantation timber for energy.
It breaks my heart to think we’d lose half our tropical forests for plantations just to save ourselves Lawrence said. It’s horrifying that we’d lose our biodiversity to avert climate change. Losing tropical forests is not somehow cheaper than putting up wind farms in the US or Sahara.
Lawrence said a steep drop in emissions to zero by 2040 would negate the need for “negative emissions” technology that would damage forests’ ability to suck up carbon, maintain local water supplies and weather patterns and provide a home for a riot of birds, mammals, insects and other creatures.
We will have a hotter, drier world without these forests Lawrence said. There needs to be an international price on carbon to fund the protection of forests. And countries with tropical forests should maintain large chunks of forests to stabilize rainfall for agriculture and keep a predictable regional climate.
The prospects for averting at least 1.5C of warming appear dim, however, with a co-author of the upcoming IPCC report warning last week the world is nowhere near on track to meet its Paris commitments.

If you care about humanity, you should be doing what you can to make your city more cyclist and pedestrian-friendly. Almost everyone benefits, especially the most vulnerable among us, including the poor, the elderly, and the lonely.
That’s one of the multitude of arguments in favor of walkability Jeff Speck author of Walkable City: How Downtown Can Save America, One Step at a Time lays out in his new book Walkable City Rules: 101 Steps to Making Better Places.
Speck, a city planner and urban designer, is passionate about making cities walkable and giving people the tools to do so. In the past, he’s sold walkable cities on the good they do for the environment, people’s health, and house prices. He describes his forthcoming Rules book, out next week, as “a tool for people who care to help them make changes.” In it, Speck introduces new data that gives walkable cities yet another selling point: equity.
If you care about the health, happiness and safety of all your residents, making your city more walkable is one of the greatest things you can do.

Walkability has a price we should pay
Because it favors urbanism Speck writes walkability is prey to charges of elitism. The most walkable neighborhoods in the US often become its least affordable because they’re very desirable. But improving walkability helps everyone, argues Speck, and particularly the poor. The same is true of making cities easier for cyclists.
Imagine a typical cyclist, and specifically someone who rides to work. Perhaps you’re thinking of a executive who switches from lycra to his suit in the gym near the office or a denim-clad techie who pedals into town with a laptop in her backpack. You’re not wrong, but you’re not exactly right either. Those people aren’t the most representative sample of those who rely on a bicycle for their commute. Instead, as the US Census Bureau reports, low-income people bike and walk to work the most. If you had to pick one person for the typical biker Speck told Quartz, it’s probably the kitchen worker getting to his shift at the fryer.
Speck lays it out in the book: There are powerful equity reasons to invest in walkability. That’s because car-centered cities only cater to the two-thirds of Americans who can drive,excluding the elderly, the vision-impaired, and people who can’t afford to have a vehicle in the first place. Cities with more transit choices demonstrate less income inequality and less overspending on rent, he writes, while better sidewalks make life easier for wheelchair users and seniors alike.
But people whom Speck describes as “demographically-challenged” don’t just suffer from their lack of a car, they suffer from other people’s cars too, which disproportionately put them at risk. Pedestrian deaths are more common in low-income areas. On top of that, people of color are 54% more likely to be hit by a car. African-Americans and Native Americans, for example, make up 12.9% of the population but 22% of pedestrian deaths. Older people are also at more risk, those over 65 are 68% more likely to be killed.

Walkable streets make connections
What about more nebulous considerations, like community or loneliness? The data stands up here, too.
People who live on heavily trafficked streets, which cater mostly to motorists, count on average about one friend. People who live on walkable streets, however, count three, and twice as many acquaintances, to boot. If your neighbors are within walking distance, and it’s easy for you to walk, it’s much more likely that you’ll bump into them, strike up a conversation, get to know them a little.
Donald Appleyard an urbanist and planner who died in a road collision in 1982, worked extensively on the relationship between social capital and traffic. He found that on light-traffic streets, residents think of the whole road as being “home territory.” On heavy-traffic streets, people seem to feel more alienated from their neighbors, feeling at home only in their own apartment or building.
The more time people spend commuting, Speck writes, the less involved they become in their local community. Researchers from the University of New Hampshire found that levels of social capital are higher in more walkable neighborhoods. Neighborhoods that are easier to get around on foot seem to encourage people to volunteer more, join in more, and get to know their neighbors, although the relevant affluence that you need to live in those neighborhoods is probably a major contributing factor.

Since the invention of the car, modern towns have been built with automobiles at their center. But we’re now paying the price, and that extends to equity.
The cities that were designed around the presumption of automobiles are actually not working at any level Speck says because they get huge congestion. Instead, the cities designed for pedestrians or cyclists are the most desirable to live in, with house prices to match.
The challenge now is on working out whether it’s possible to retrofit car-centric cities for a population on foot, or two wheels.
Speck has a few ideas that he lays out in the book. Planners have an arsenal of tools at their disposal, ranging from the gentle (creating bike-shares that work or building more parks) to the aggressive (tearing down a highway or adopting what Speck describes as “visionary proposals”).
In the end, short-term wins can only do so much to fix bad underlying design. If planners really want all the humanitarian or economic benefits of walkability, they have to be all in, Speck writes: The ordinary fabric of a city can make it very good, but only big dreams make a city great. In attending to the day-to-day, we can’t forget to pursue greatness as well.

Moscow-based architect and designer Elena Mitro has devised a research project that utilizes plants to produce renewable energy. aptly titled ‘green spark’
The system is represented by a set of plant-filled ceramic pots that act as a set of batteries using the natural process of photosynthesis to generate electrical energy known as plant-microbial fuel cells (PMFCs).
Each battery comprises a modular hanged ceramic pot that contains different species of plants. these plants use light energy to consume carbon dioxide and water from the environment and convert it to organic compounds. These compounds are released through the roots to the soil where a symbiotic bacteria occurs.

The bacteria breaks down the matter, liberating free electrons. by providing an electrode, so a conductor through which electricity can enter, electricity can be harvested from the micro-organisms. one battery can generate up to 0.7 volts with the current depending on the way the pots are connected, either parallel or in a series circuit.
Elena Mitro has created a final installation that contains 86 such batteries which allows to charge 2 smartphones simultaneously. The project goal is to test PMFCs through the integration to the city scale and urban infrastructure. The green batteries could represent a self-sufficient distributed system for the environmental eco-monitoring.

The battery cells have been specially designed to encourage the plant to cling as if in its natural surroundings. The bottom part of the ceramic pot is glazed to be waterproof for a better activation of cathode, an electrode from which a conventional current leaves a polarized electrical device. The rest is a porous clay without coating. The pot has three lugs, two for the electrical connection and one for an irrigation tube.