Hög andel grönyta ger miljöfientlig stad

Det är inte andelen grönyta som spelar nån roll för människor i en storstad, det är hur grönytorna ser ut, hur de ligger och deras användbarhet som har betydelse. Hög andel grönyta resulterar dessutom oftast i en stad som är negativ för miljön och klimatet. Göteborg har enligt SCB:s statistik 55 % grönområden och Stockholm har 47 %, Malmö har bara 16 %, men ändå upplever jag det lättare att hitta grönområden i Malmö än i Göteborg.

Det beror på att en stor del av grönområdena i Göteborg är oanvändbara bergsstup, oplanerade vilda skogar och impediment kring vägar, industriområden och järnvägar. Kort sagt områden som är oanvändbara. Dessutom finns inom Göteborgs kommun stora landsortsområden både på Hisingen och i nordost som gör att andelen grönyta går upp. Stockholm har liknande områden på Järvafältet. Stockholm har också något som de andra två städerna saknar och som också ger rymd och luft i staden. Större tillgång till öppna vattenområden.

Andelen grönområden säger inte allt, i SCB:s rapport uppger man att 220 000 människor inte har tillgång till ett grönområde i närheten av sin bostad, motsvarande siffror i Göteborg är 57 000 personer och i Malmö 46 000 personer. I alla tre städerna upptar vägar och liknande ytor stora ytor och är en del av den bebyggda ytan som inte kan utnyttjas av människor.

Bebyggelsen i Göteborg är alltså gles och utspridd med konsekvensen att kollektivtrafiken är dålig och dåligt utnyttjad. I Göteborg görs endast 25 % av alla resor med kollektivtrafiken, i Stockhom cirka 40 % . I Malmö kan man gå eller cykla överallt. I Göteborg är det extremt svårt att cykla och gå till många ställen. Det tar lång tid och är besvärligt. Göteborg är en sämre miljöstad än Stockholm och Malmö när det gäller trafiken och resandet. Hög andel grönområden är en del av problemet snarare än en del av det som kan gör en stad miljövänligare. Hur en miljövänlig och klimatvänlig stad borde vara kan illusterars med utdrag ur en text ur en US-amerikansk tidning, New Yorker:

My wife and I got married right out of college, in 1978. We were young and naïve and unashamedly idealistic, and we decided to make our first home in a utopian environmentalist community in New York State. For seven years, we lived, quite contentedly, in circumstances that would strike most Americans as austere in the extreme: our living space measured just seven hundred square feet, and we didn’t have a dishwasher, a garbage disposal, a lawn, or a car. We did our grocery shopping on foot, and when we needed to travel longer distances we used public transportation. Because space at home was scarce, we seldom acquired new possessions of significant size. Our electric bills worked out to about a dollar a day.

The utopian community was Manhattan. (Our apartment was on Sixty-ninth
Street, between Second and Third.) Most Americans, including most New Yorkers, think of New York City as an ecological nightmare, a wasteland of concrete and garbage and diesel fumes and traffic jams, but in comparison with the rest of America it’s a model of environmental responsibility. By the most significant measures, New York is the greenest community in the United States, and one of the greenest cities in the world. The most devastating damage humans have done to the environment has arisen from the heedless burning of fossil fuels, a category in which New Yorkers are practically prehistoric. The average Manhattanite consumes gasoline at a rate that the country as a whole hasn’t matched since the mid-nineteen-twenties, when the most widely owned car in the United States was the Ford Model T. Eighty-two per cent of Manhattan residents travel to work by public transit, by bicycle, or on foot. That’s ten times the rate for Americans in general, and eight times the rate for residents of Los Angeles County. New York City is more populous than all but eleven states; if it were granted statehood, it would rank fiftyfirst in per-capita energy use.

[…]

New York’s example, admittedly, is difficult for others to imitate, because the city’s remarkable population density is the result not of conscientious planning but of a succession of serendipitous historical accidents. The most important of those accidents was geographic: New York arose on a smallish island rather than on the mainland edge of a river or a bay, and the surrounding water served as a physical constraint to outward expansion. Manhattan is like a typical seaport turned inside out—a city with a harbor around it, rather than a harbor with a city along its edge. Insularity gave Manhattan more shoreline per square mile than other ports, a major advantage in the days when one of the world’s main commercial activities was moving cargoes between ships. It also drove early development inward and upward.

A second lucky accident was that Manhattan’s street plan was created by merchants who were more interested in economic efficiency than in boulevards, parks, or empty spaces between buildings. The resulting crush of architecture is actually humanizing, because it brings the city’s commercial, cultural, and other offerings closer together, thereby increasing their accessibility—a point made forty-three years ago by the brilliantly iconoclastic urban thinker Jane Jacobs, in her landmark book “The Death and Life of Great American Cities.”

A third accident was the fact that by the early nineteen-hundreds most of Manhattan’s lines had been filled in to the point where not even Robert Moses could easily redraw them to accommodate the great destroyer of American urban life, the automobile. Henry Ford thought of cars as tools for liberating humanity from the wretchedness of cities, which he viewed with as much distaste as Jefferson did. In 1932, John Nolen, a prominent Harvard-educated urban planner and landscape architect, said, “The future city will be spread out, it will be regional, it will be the natural product of the automobile, the good road, electricity, the telephone, and the radio, combined with the growing desire to live a more natural, biological life under pleasanter and more natural conditions.” This is the idea behind suburbs, and it’s still seductive. But it’s also a prescription for sprawl and expressways and tremendous waste.

New York City’s obvious urban antithesis, in terms of density and automobile use, is metropolitan Los Angeles, whose metastatic outward growth has been virtually
unimpeded by the lay of the land, whose early settlers came to the area partly out of a desire to create space between themselves and others, and whose main development began late enough to be shaped by the needs of cars.

But a more telling counterexample is Washington, D.C., whose basic layout was conceived at roughly the same time as Manhattan’s, around the turn of the nineteenth century. The District of Columbia’s original plan was created by an eccentric French-born engineer and architect named Pierre-Charles L’Enfant, who befriended General Washington during the Revolutionary War and asked to be allowed to design the capital. Many of modern Washington’s most striking features are his: the broad, radial avenues; the hublike traffic circles; the sweeping public lawns and ceremonial spaces.

Washington is commonly viewed as the most intelligently beautiful—the most
European—of large American cities. Ecologically, though, it’s a mess. L’Enfant’s
expansive avenues were easily adapted to automobiles, and the low, widely separated buildings (whose height is limited by law) stretched the distance between destinations. There are many pleasant places in Washington to go for a walk, but the city is difficult to get around on foot: the wide avenues are hard to cross, the traffic circles are like obstacle courses, and the grandiloquent empty spaces thwart pedestrians, by acting as what Jane Jacobs calls “border vacuums.” (One of Jacobs’s many arresting observations is that parks and other open spaces can reduce urban vitality, by creating dead ends that prevent people from moving freely between neighborhoods and by decreasing activity along their edges.) Many parts of Washington, furthermore, are relentlessly homogeneous. There are plenty of dignified public buildings on Constitution Avenue, for example, but good luck finding a dry cleaner, a Chinese restaurant, or a grocery store. The city’s horizontal, airy design has also pushed development into the surrounding countryside. The fastestgrowing county in the United States is Loudoun County, Virginia, at the rapidly receding western edge of the Washington metropolitan area.

Mina personliga erfarnehter av Manhattan är att var man än är så är det faktiskt nära till ett grönområde av nåt slag. Undantaget är delar av Downtown, Soho med omgivningar  och delar av Finance District. Det är förstås Central Park som i först hand gör att det blir på det viset, men även mindre parker. Manhattan är förstås också en perfekt miljö för en god kollektivtrafik. En bar kollektivtrafik kräver nämligen hög befolkningstäthet, dvs tät bebyggelse. Tillbaka till krönikan om New
York igen:

New York City looks so little like other parts of America that urban planners and environmentalists tend to treat it as an exception rather than an example, and to act as though Manhattan occupied an idiosyncratic universe of its own. But the underlying principles apply everywhere. “The basic point,” Jeffrey Zupan, an economist with the Regional Planning Association, told me, “is that you need density to support public transit. In all cities, not just in New York, once you get above a certain density two things happen. First, you get less travel by mechanical means, which is another way of saying you get more people walking or biking; and, second, you get a decrease in the trips by auto and an increase in the trips by transit. That threshold tends to be around seven dwellings per acre. Once you cross that line, a bus company can put buses out there, because they know they’re going to have enough passengers to support a reasonable frequency of service.”

Phoenix is the sixth-largest city in the United States and one of the fastestgrowing among the top ten, yet its public transit system accounts for just one per cent of the passenger miles that New York City’s does. The reason is that Phoenix’s burgeoning population has spread so far across the desert—greater Phoenix, whose population is a little more than twice that of Manhattan, covers more than two hundred times as much land—that no transit system could conceivably serve it. And no amount of browbeating, public-service advertising, or federal spending can change that.

Cities, states, and the federal government often negate their own efforts to nurture public transit by simultaneously spending huge sums to make it easier for people to get around in cars. When a city’s automobile traffic becomes congested, the standard response has long been to provide additional capacity by building new roads or widening existing ones. This approach eventually makes the original problem worse, by generating what transportation planners call “induced traffic”: every mile of new highway lures passengers from public transit and other more efficient modes of travel, and makes it possible for residential and commercial development to spread even farther from urban centers. And adding public transit in the hope of reducing automobile congestion is as self-defeating as building new highways, because unclogging roads, if successful, just makes driving seem more attractive, and the roads fill up again. A better strategy would be to eliminate existing traffic lanes and parking spaces gradually, thereby forcing more drivers to use less environmentally damaging alternatives—in effect, “induced transit.”

One reason New Yorkers are the most dedicated transit users in America is that congestion on the city’s streets makes driving extraordinarily disagreeable. The average speed of crosstown traffic in Manhattan is little more than that of a brisk walker, and in midtown at certain times of the day the cars on the side streets move so slowly that they appear almost to be parked. Congestion like that urges drivers into the subways, and it makes life easier for pedestrians and bicycle riders by slowing cars to a point where they constitute less of a physical threat.

Vill man ha minskad bilism, ökat kollektivtrafikåkande och en miljö- och klimatvänligare stad ska man sluta bygga trafikleder och dessutom gärna riva en del existerande. Sålunda bör inte Förbifart Stockholm eller Marieholmstunneln i Göteborg byggas. Att varna för att gönområden kan bli en bristvara i storstäder är också att skjuta sig själv i foten. Problemet ligger inte där. Problemet ligger i hur grönområdena ser ut, hur de ligger och om de är användbara eller inte. Andelen grönområden kan vara mycket lägre än det är i Stockholm och Göteborg, men man kan ändå uppelva en stad som grönare om det görs på rätt sätt.

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Läs även andra bloggares åsikter om Grönområden, Kollektivt åkande, Biltrafik, SCB, Tätbebyggd stad, Sprawl, Stockholm, Malmö, Göteborg, New York, Manhattan, USA, Kollektivtrafik, Bilism, Miljö, Stadsplanering, Parker, Samhälle, Politik