Climate change could help bring a viral disease called chikungunya to New York City. And if you live there, you miiiight want to get a little freaked out about this, because as LiveScience reports, chikungunya makes swine flu look like piglet sniffles.

Chikungunya causes severe joint pain, fever, rash and other symptoms that can last for months, even years, and in unusual cases, death. There is no vaccine and no treatment.

Photo by Daniel.

L.A. gets a bad rap for its car culture. But it turns out that Americans' addiction to milk, cheese, and other delicious dairy products plays just as big a role in the city's smog problem these days. Scientific American reports that there are 300,000 cattle in the L.A. area, and the bacteria feasting on their waste create the same tiny particles of pollution that make smog particularly nasty.

Jane Jacobs.

In two hours of wandering slowly down Broadway last Sunday, I heard about a solar installation over on FDR drive, the number of bird species that can be seen in New York City (roughly half of all that appear in North America), and an Astor Place riot sparked by two rival productions of Macbeth, one marketed to New York’s upper echelons, the other to its less savory elements. Along with a group of other sightseers, I gazed up at former tenements and butter and egg factories now converted into condos and office buildings. We talked about other neighborhoods we’d visited.

But one thing we did not do was talk very much about Jane Jacobs, her work, or her ideas. Funny, Jacobs was the reason we were all there.

This past weekend, in 85 cities around the world, there were at least 580 different ways to honor the legacy of Jacobs -- writer, grassroots organizer, patron saint of city lovers everywhere. All of them involved walking -- many of them took place under the umbrella of the Toronto-based organization Jane’s Walk -- but the similarities pretty much ended there.

In the Netherlands, there are more than 30 "Repair Cafes" -- groups that meet once or twice a month to repair (for free!) clothes and gizmos and tools that might otherwise be discarded. The New York Times visited the original Repair Cafe, which began two and a half years ago, and found that people want to keep their stuff -- even cheap stuff, like H&M skirts. They just don't know how to mend it themselves:

“This cost 5 or 10 euros,” about $6.50 to $13, [Sigrid Deters] said, adding that she had not mended it herself because she was too clumsy. “It’s a piece of nothing, you could throw it out and buy a new one. But if it were repaired, I would wear it.”

The group repairs electronics, too -- everything from big-ticket items like vacuums and washing machines to the little gadgets that go haywire, like irons, toaster ovens, and coffee pots.

Woe betide you if you decide to drive your ironic vintage Yugo in Brooklyn instead of your fixed-gear bike with detachable mustache. Park Slope residents have had enough of those bullshit half-spaces that show up in front of cars when someone moves an SUV and it gets replaced by a compact. They're so pissed off, they're hauling out their letterpresses and feverishly hand-pulling artisanal parking tickets.

This allergy season has been terrible. It seems like everyone I know has been running around with leaky eyes, even those of us who aren't typically pollen-sensitive. Granted, there was an unusual amount of tree sperm in the air this year, but it seemed strange that everybody -- really, everybody! -- was afflicted. But a new study by Finnish researchers explains everything: The reason we’re all so sick is that we live in the city.

According to this study, published in Proceedings of the National Academy of Sciences and based on research done in Finland, people who live in cities are more prone to developing allergies and asthma because their environments lack biodiversity. That’s not biodiversity as in “not enough kinds of cuddly wildlife” (although that too!) -- it's about the diversity of bacteria that live on your skin. If you live in the city, these freeloaders are less varied, and that spells trouble.

I'll admit that I attended one TINY textbook fire as a teenager. It was somebody's math book, and we just stuck it in a park barbecue and then melted some cups over it, nothing particularly Fahrenheit 451. But there are better ways to dispose of textbooks that you hate, or just don't need anymore, but for whatever reason can't sell back. Chinese artist Liu Wei, for instance, does it by making spectacular carved-book cityscapes.

Photo by Shannon Donegan.

A version of this story originally appeared on Sightline.

I fell in love with cycling during six months I spent traveling the world’s great bicycle cities. The ease, safety, convenience … (dreamy sigh)

But as my trip came to an end, I began to realize the reason for my infatuation: Residents of cities like those in Denmark and Holland inject cycling with fun, whimsy, and even romance.

Certainly, many Americans love their bikes, but even more of us would if we learned these five lessons on cycling’s soft side from the world’s active-transport capitals.

It's all very well to talk about the urban jungle, but how often are you supposed to water it? Carmichael Collective's tongue-in-cheek urban plant tags offer care instructions for metropolitan flora like benches, fire hydrants, stop signs, and mailboxes.

Photo by Bastien Vaucher.

This year marks the 10th anniversary of our Ask Umbra advice column, and to celebrate, we’re pulling one particularly poignant question or tidbit of eco-advice out of the archives each week. Today, a question from a bicyclist in Berkeley:

"My skirt gets caught in the bicycle chain ... Do you know any wonderful manufacturers out there who can solve my problem?"

Read on to see Umbra’s answer. Plus: She shares a website that’ll show you how to make your own “skirt guard.” And don’t you go anywhere, fellas: It works for kilts and coat tails, too.