Posts by Gabe

What a wild five months it’s been since I last wrote on this  blog! I’ll admit, there are days when I envy political reporters uncovering the latest White House shockers that keep us refreshing our browsers hourly (or more often?) and writing the first draft of a remarkable and troubling period in our country’s history. But most days I’m grateful to be able to range farther afield and explore the great world of science and its impacts on us — and perhaps provide a glimmer of hope that we will move beyond this dark moment into a saner future. With that in mind, here’s an update on what I’ve been up to so far in 2017.

This February I traveled to Panama — the farthest south I’ve ever ranged — to report for Smithsonian Magazine on scientists teaming up with indigenous groups to protect forests and the climate. Most scientists operate out of a pretty standard playbook — they come up with their own research agendas, and work and publish papers with other scientists. Catherine Potvin and Javier Mateo-Vega, the McGill University-based scientists I profiled in this piece, turn this upside-down. They ask indigenous communities what research they would like to pursue, find funding to support it, include community members as collaborators and coauthors, and return results to communities. I don’t know anyone else who does science this way, and it was a privilege to tell their story.

Following Javier Mateo-Vega up a forested mountainside in Ipeti, Panama

On an earlier trip south, I visited Mayan farmers in Mexico’s Yucatán peninsula who are pioneering techniques that could help save milpa, one of the world’s most ancient farming practices, in the era of climate change. My story on their efforts to spread the practice was published in February on NPR’s food blog.

Hanging with milperos Gualberto Casanova and Dionisio Yam Moo in the Yucatán

At the other extreme, I didn’t even have to leave my house here in Mount Rainier, Maryland for a front-row seat to the development and construction of four of the country’s greenest homes. Literally outside my office window, two young, ambitious developers constructed homes that are as energy efficient and environmentally friendly as any in the DC area and perhaps the nation. Not everything went smoothly, as you might expect, and whether the homes will launch a green building movement in the DC area or nationally remains to be seen. I told their story for the Washington Post Magazine.

Developers John Miller and Jessica Pitts planting their green roof

Though these three stories are unrelated, on a day when Donald Trump has pulled the U.S. out of the Paris accord, it strikes me that we’ll need a lot more of these kinds of grass-roots efforts if we as a global society are going to avert dangerous climate change. If you know of climate optimism stories that aren’t being told, please send them my way!

Moving on to less weighty subjects for a moment.. If you follow my writing long enough, you will learn that I have a perhaps uncommon fascination with how physics, the subject I studied in college and remain intrigued by, is shedding light on the incredibly complex world of biology and ecology. This spring, I had several chances to delve into aspects of this topic: I wrote about how physicists are explaining the strange and wondrous world of bacteria; how chaos theory may help predict red tides; and how a simple measurement could predict ecosystem collapse.

And I got to indulge in one of the purest joys of science writing: geeking out on amazing new/future technology. In a recent story for Nature I reported on private satellite companies breaking into sophisticated technologies that so far have been the sole purview of government agencies such as NASA. And early this year I wrote, also for Nature, about an effort to send tiny space probes 4.2 light-years to the nearest star — which some days doesn’t sound like such a bad place to go!

Any time I’m not tied to my computer working on a story, I try to get outside to interesting and beautiful places. This spring I went to Germany for a family reunion and vacation, and spent time in my beautiful, green (and yes, also red) home state of Kentucky. Here are a couple photos from those trips.

The Neisse River separating Germany and Poland (note the Polish marker on the east bank). No wall here!

A monster oak tree in Griffith Woods, one of Kentucky’s most amazing and least visited places

The narrative arc of this email demands, of course, that we return to where we began, indeed where everything seems to begin and end these days, namely politics. Shortly after the inauguration, I was invited to write an op-ed for Scientific American on a serious and growing problem: increasing impediments to speaking with scientists working in the federal government. While this might seem like small potatoes compared to much of what we’ve seen from this administration, such barriers are in fact a tried-and-true method for making citizens less informed and less effective at holding their government accountable, and, over time, for eroding democracy. Trump is hardly alone in wanting to keep the media at arm’s length, but his anti-press rhetoric and actions go far beyond what we’ve seen from any recent president, and it’s incumbent on all of us to resist attempts to quash press freedom. As a small piece of this effort, a group of us science writers, under with support from the National Association of Science Writers, are now organizing a meeting to bring together journalists and government public affairs officers, to try to open more channels of communication between government scientists and the public. We will likely meet in late summer or fall; please let me know if you’d like to be involved in the effort.

My end-of-year message

Once again I find myself arriving at the end of the year having lagged in sending email announcements. This year, in addition to the usual busy-ness and general discomfort with promoting myself, I have another excuse: I haven’t felt particularly inspired to tout my own little accomplishments when much larger things are going wrong in the world.

Still, it would be remiss to let the year change without writing something. So I want to take the opportunity to do something a little different this time: before sharing a few of what I feel are my most important stories from 2016, I want to first ask for your help. I became a science writer in part because I thought it would be a fun and interesting career (which it is), and in part because I felt that building bridges between the technical world of science and the non-scientist public would be a worthwhile thing to do. I still believe that, but when our country just elected an anti-science president, I find my belief in the inherent value and impact of science writing somewhat shaken. Clearly we science writers are failing to connect with large swaths of the public we aim to serve — a public that increasingly views science at best as something esoteric and irrelevant to their lives, and at worst as a political tool used by elitists in Washington and elsewhere to manipulate them and restrict their freedoms.

I want to find ways to change that. I want to find and tell stories that will connect with all kinds of readers, not just those who share my basic assumptions about the value and importance of science. I want to tell stories that will make clear what role science plays in our world, and that will hold both scientists and science deniers or manipulators accountable. I am always on the lookout for such stories, of course, but I can only see, hear and read so much. So I would like to ask you to be on the lookout too, and let me know when you come across them. (For those of you who are also writers, I might tweak this appeal a bit: let me know if you find a story you’re unable to do yourself — or if you ever want a collaborator.)

Now to turn to my regularly scheduled update. When I look back on 2016, two pieces that stand out were published within a day of each other in early October. The first was my third New York Times op-ed, Update the Nobel Prizes. I have long marveled at how the Nobel organization has set itself apart as the world’s scientific king (and, not frequently enough, queen) maker. All too often, science writers and others use “Nobel laureate” as a sort of shorthand for genius. But this is problematic, because the Nobel glory is far from equally available to everyone. I and others have documented the prize’s long-standing gender inequality problem, but this year I looked at a different kind of inequality: the fact that scientists of many disciplines are completely shut out of Nobel contention simply because there is no prize recognizing their field. Now we’ll have to wait til next October to see if the organization takes my advice!

The second was a profile in Nature of Matt Hansen, a geographer at the University of Maryland. I first heard of Hansen in late 2013 when he published a set of global forest cover change maps based on satellite data. From then on, it seemed that everyone I talked to who was working on forests inevitably mentioned the “Hansen maps”. So one day I biked over to the university (literally down the road from me) to find out what made his work so unique and high-impact. I found that Hansen is truly the anti-ivory tower academic — everything he does is with an eye toward making a difference in the real world. And like everyone doing high-profile work, he has his critics. I hope I was able to present both sides fairly.

Another story that started with a chat with a local scientist was my feature in Science on progress on quantum computers. Quantum computing is a challenging topic to cover, because while there are always new papers being published (and promoted), any commercial technology still seems a long way off. But there is reason to think this could be changing: major private companies like Google and Intel, as well as venture capital firms, are getting into the field in a big way. Private funders, like governments, can of course take long-shot bets on new technologies just to make sure they don’t miss out on a big payday, and this flurry of interest could be an example of that, but I do think it represents a sizable step forward in seriousness for the field. Don’t be surprised if you start to see quantum technology seeping into our world in the coming years.

Speaking of physics, I continue to be interested in how this sometimes cloistered field, which I long ago studied in school, intersects with other parts of science, especially biology. This year that took the form of a story on physicists taking an unconventional approach to studying cancer, for the online magazine Quanta.

I have also started looking more deeply into how science interacts with parts of society that it has historically excluded. I wrote this summer for Nature about collaborations between scientists and indigenous communities, and recently wrote for Smithsonian about how protected areas — the kinds of places we in America love to visit on family road trips — can sometimes be counterproductive both for forests and people who live in them. I have every intention of continuing to pursue these kinds of stories, and welcome any leads.

Lastly, I took a brave stand against tree anthropomorphism, in a book review for Science and an essay for Aeon. I love trees, as anybody who has ever stepped outside with me knows. But I don’t think we need to pretend they are like people. We should strive to understand them on their own terms.

I will also strive, again, to use this email list more regularly in 2017. But for those who might want up-to-the-minute news of my latest work, I post almost everything I write on Twitter (@gabrielpopkin) and Facebook, and of course on this website.

I will close with something out of character: a political message. Whatever you think about the result of the presidential election, I think we can all agree it was a loss for democracy. Donald Trump is about to become president despite receiving almost three million fewer votes than Hillary Clinton. More than 40% of eligible voters — far more than voted for Clinton, much less Trump — didn’t vote at all. And I am hardly the first to observe that many democratic norms that we have always taken for granted in this country — respecting the legitimacy of opposition parties and politicians, upholding the universal right to vote, respecting the sanctity of basic rights and freedoms — are being eroded.

Folks, democracy is not a spectator sport; it is a participatory sport. If we don’t participate, it will go away. There are many ways to participate — through our votes, through our work, through our involvement in our communities, through how we spend our time and our money, and, if necessary, through nonviolent protest. I know I have been doing some soul-searching about how I can more actively and effectively participate. If you are too, I would like to highlight one way: support independent media organizations, the kinds of places that employ people like me. It’s expensive to produce high-quality journalistic stories. It requires paying writers and editors (and believe me, we are not overpaid), paying computer programmers and web designers and artists, paying audio and video producers, and, unless a place is going to abstain from publishing anything that challenges any powerful person or institution, paying lawyers to defend against attempts to stifle press freedom.

I realize this will not be news for some of you, but the main revenue source for media historically — advertising — has been eaten away for two decades by the Internet, and more recently by social media platforms like Facebook. The other revenue source (other than the occasional magnanimous billionaire) is people like us. I know it can seem pointless to spend money on subscriptions and donations when an endless deluge of free media is available 24/7. And I know the media stumbled badly with the election. Support them anyway. Otherwise, there will be nobody to hold the Trump administration and all the private interests that stand to benefit from it accountable, and we will stumble further down the road toward an undemocratic society.

This is hardly an exclusive list, but places I find to be doing the kind of tough journalism that we need to support include the New Yorker, New York Times, Washington Post, the Guardian, NPR and the Intercept. You may have your own favorites, and that’s fine. I just ask you to set aside whatever you can afford to support a healthy independent media, as you would for other causes you feel strongly about.

And lest this message end on too dire a note, I want to say that not every story and not every publication needs to be devoted exclusively to challenging the powerful and fighting for democracy. There is still room for stories that are fun, stories that are interesting, and stories that are beautiful. And publications that specialize in those kinds of stories. I hope to do some of all of the above in the coming year.

Thanks for hearing me out, please let me hear from you, and I hope you have a great end to a not-so-great year.

I recently wrote an op-ed for the New York Times, about the Bradford pear tree. The Bradford pear is not my favorite tree or even a tree I particularly like, but I thought it needed a defender, because it has, in my opinion, been unfairly made a scapegoat for all kinds of problems not of its own making.

Riverdale pear

Though it is a tree, and therefore ostensibly part of “nature,” the Bradford pear is unquestionably a human creation. It was brought into being by scientists, promoted by a first lady and countless nursery companies, disseminated in what must have been a veritable orgy of street planting, and now hacked into awful shapes by utility crews trying to keep it from dropping branches onto power lines. Birds spread its seeds to parks and stream banks and other “natural areas,” where it offends people who want to see only native plants.

But I don’t think it’s the pear we should be offended by. We should be offended by ourselves. The pear thrives precisely where we have abused nature, which is to say almost everywhere. (In the interest of accuracy, I should note that it’s the Callery pear that is ubiquitous. Bradford is a specific cultivar of Callery pear that comes from nurseries, but that can hybridize with other pear varieties to produce viable seed.) Where I live, in Maryland near the Anacostia River—the sad, channelized, silted-up sidekick of the Potomac—the abuses have been piled on top of abuses so we can’t see them anymore. In the past four centuries, what was once forested wetland has been drained, cleared, plowed, planted in tobacco and other crops, perhaps grazed after the soil eroded and wore out, dumped on and then abandoned by industries whose skeletons still populate the landscape, and now carved into a million suburban lots. The Callery pear, which loves disturbed soil, forest edges and sunny areas, does wonderfully here.

When you write about some piece of the world, you become sensitized to it. Annie Dillard described this as being like a bell, ready to be rung. This spring, I am being rung by the Callery pear. I have never noticed before how ubiquitous it is. Now I see the trees everywhere, rising from the land like puffy white clouds.

It baffles me that people walk out of their houses, get into their cars, drive on four-lane highways past strip malls to little patches of green, and see non-native plants as the piece of the landscape that is out of whack. Yes, Callery pear may compete with native species for resources, but I highly doubt it has ever driven anything extinct. In fact, I wonder if any plant has ever been responsible for an extinction*. Our houses and cars and roads and strip malls eradicate native plants for more effectively than any introduced plant ever will.

I am not arguing, by the way, that we should just open our borders and let in all species. Introduced species can cause huge problems. One species of fungus, Batrachochytrium dendrobatidis, has driven more then 100 amphibians to extinction—mostly in the tropics so far, but it could arrive here. The fungus that causes white nose disease has reduced populations of some of our native bats by more than 90%. Chestnut blight (a fungus) and Dutch elm disease (a fungus spread by an insect) have all but wiped out two of our great native trees, and hemlock woolly adelgid (an insect) and emerald ash borer (another insect) are currently destroying two more. What do all of the above scourges have in common? They’re not caused by plants. And yet, it’s the introduced plants that get people all worked up. See here and here and here for examples of fury toward the Bradford pear. Just try to find anything approaching this level of anger directed toward a fungus or an insect!

If we care about native plants, cutting down pear trees is not the answer. Instead, we should better fund our port inspection service, so it can effectively screen cargo entering the country for plants that could be carrying new diseases or pests. We should also jackhammer up most of our streets and demolish the strip malls and box stores. We should all move into tiny apartments and become vegetarians and get rid of our cars and do everything we can to minimize the amount of land we need to sustain ourselves, as E. O. Wilson seems to be suggesting in his latest book. The native plants don’t need us to spend weekend mornings ripping out weeds; they mostly just need unfragmented, undisturbed land and relief from diseases and pests.

Of course we’re not going to give them that, because we’re doing quite well with our cities and suburbs and exurbs and farms and our global trade, thank you very much. In fact, we’ve never had it better; we are the wealthiest and most comfortable society the planet has ever been home to, and that’s largely a result of how we’ve exploited land and moved species around. What we call “invasive plants” are really a byproduct of our own behavior.

They’re also a quintessential first-world problem. They’re what we worry about when we don’t need to worry about having enough food to eat, or being sick, or being killed in a war, or working three jobs to get by, or breathing dirty air or drinking polluted water. In a world with so many urgent problems to solve, we should question the impulse to tidy up little pieces of nature. What else could we be doing with our time and energy? Maybe fighting inequality? Saving our remaining old-growth forest? Saving lives?

It’s time to get over the Bradford pear. There are far more important things to worry about.

*Originally this sentence ended with “…or even an extirpation.” My biologist friends have convinced me that extirpations have been documented where invasive plants are widespread. I would still argue that the question of responsibility (human versus plant) should be further explored, but will leave that for another time.

Snow — in enough quantity — changes almost everything. It shrinks the accessible world to a few blocks. It makes many things impossible (driving, biking, flying) and other things possible that weren’t before (skiing, snowmen, snow angels). It buries unsightly trash, clothes bare tree limbs, and records the otherwise mysterious motions of animals.

Snow quiets for a few hours the ceaseless movement of people, stills restless cities.

Snow is the great equalizer. It obscures human boundaries and ambitions and renders them temporarily meaningless. It turns fancy cars and aging clunkers alike into shapeless, useless lumps. It mocks plans, even those of the powerful.


There’s something irresistibly comic about snow — its slipperiness, its softness, its absurd, almost indecent voluminousness. It makes children and full-grown professional adults alike want to flop and roll on the ground, hurl things at each other and hurl themselves down hills on bits of plastic, laughing.

Snow casts its spell on us writers as well. Poets and would-be poets can’t resist it. Reporters can’t either, though perhaps they should; surely everything that could ever be written about a snowstorm has been written by now. But the public wants to know, so a predictable stream of tired adjectives pours forth from probably equally tired politicians and newspaper reporters. “Crippling,” “paralyzing,” “epic,” and, of course, “historic.”

And as those politicians and newspapers never tire of reminding us, snow can cause deaths. It can supposedly also cause babies.

Snow shows us what our world could be like. For three straight nights this past weekend, a group of friends, robbed of whatever plans we may have had for the weekend by the rather inelegantly named Snowzilla, gathered, ate, drank, told stories and played music late into the night. The morning after the storm, people — young and old, women and men, black, white and Latino — were out shoveling off sidewalks and cars. They laughed and joked in the startlingly bright sunshine. Neighbors helped each other, pushing stuck cars, digging each other out. In the seven years I’ve lived in my current hometown, with the possible exception of the line I stood in to vote for Obama in 2008, I have never seen so many residents outside at one time.

Yet, how quickly snow wears out its welcome. The 17.8 inches (or more) that fell last weekend haven’t yet melted, and won’t for some time, but already they’ve been pushed aside, piled haphazardly on the curb like so much old furniture. People have returned indoors and inward, working and griping about impassable roadways. I mourn this return to normalcy, which to a large extent means the return of the car and the return to work. Couldn’t we have held on to our shrunken, snowbound world just a little longer?

Snow is, in the end, ephemeral, and so is its power to cover up the world’s ugliness. As two friends and I skied on the half-plowed streets yesterday, we had to step aside for a car attempting to climb an icy hill. It was an older car, with front-wheel drive, clearly no match for the conditions. A piece of plastic that shields the engine compartment had partially broken off and was dragging on the ground. The car’s tires spun uselessly and water vapor belched from the tailpipe. “Why try to drive a car like this on a day like this,” we wondered, but the driver was clearly not out for a joy-ride. He had on a private security guard uniform, and his employer probably didn’t care if roads were unplowed and Metro was shut down. A business or government building can be broken into whether open or closed. And a person can lose their job for not showing up to that building.

It was an important reminder: Snow may fall indiscriminately, but it doesn’t distribute its joy equally. For that to happen, we all still have work to do.

This blog has been pretty inactive in 2015, but I figured I could at least post my 2015 roundup. Enjoy!

It’s been, among other things, a year of trees and forests. In June, for my first feature story in Nature, I reported on scientists’ efforts to measure how much carbon the world’s forests store, and how much more (or less) they’re likely to store in the future as the climate continues to warm. Despite decades of measuring trees with tapes and peering at forest canopies from airplanes and satellites, scientists are still grappling with a lot of uncertainty around this question, which is vital to efforts to predict and slow climate change. In a related story, I reported on an analysis released at last month’s climate talks showing that at least 20% of tropical forest carbon is in territories managed by indigenous people. And I recently profiled for APS News (incidentally the first publication I ever wrote science for) three physicists who are advancing the science of studying forests from the sky.

Moving closer to home… if you’ve hung out with me in the last three years, especially outdoors, you’ve probably heard me talk about the eastern hemlock tree, which is threatened by a tiny but deadly invasive insect called the hemlock woolly adelgid. I wrote a feature story for Science about efforts to control the adelgid and save some of the last old-growth forests in the eastern U.S. This was the culmination of more than two years of reporting and research, including visiting forests and scientists from Georgia to Massachusetts. While it was gratifying to write this story, the battle to save the hemlock is far from over, and I continue to look for ways to bring attention to this and other threats to our beautiful forests.

Among the hemlocks at Cook Forest, PA. Photo Emily Townsend

Along those lines, I will share some of what I’ve learned about trees and forests at an upcoming D.C. Science Café, probably on Tuesday, March 2, at Busboys and Poets’ 5th and K Street location in downtown Washington. I hope that some of you who are local will be able to attend. Matthew Hansen of the University of Maryland and Earl Eutsler of D.C.’s Urban Forestry Administration will also speak, and it should be a fascinating evening.When I wasn’t exploring forests, I might have been on the coast. This fall I wrote a feature story for Science on living shorelines, a strategy for preventing erosion while restoring rather than destroying coastal ecosystems. I also wrote my first story for Quanta magazine about marine ecologist George Sugihara, who uses chaos theory to predict the future of fisheries and other complex systems. (OK, I didn’t actually go anywhere other than the Ecological Society of America meeting in Baltimore for that story, but it was still a fun one.)

Speaking of water, despite living less than an hour from it, I haven’t spent nearly enough time on it lately. A fantastic outfit called the Institute for Journalism and Natural Resources helped correct this, by inviting me to travel up and down the Bay from Baltimore to Tangiers Island and learn about environmental issues that could lead to future stories. On the way I put on my first hazmat suit and set foot in my first chicken factory farm. (Chicken farming on Maryland’s Eastern Shore is one of the reasons the Bay is so polluted.) And lest the West Coast feel left out, I also fulfilled a long-held dream and hiked with a friend in the rainforest and along the beach in Olympic National Park—a beautiful park that has both 300-foot trees and beach! Highly recommended.

Eating crabs with IJRN colleagues on the Chesapeake Bay. Photo Tristan Baurick

Me and a big tree in Olympic National Park, WA. Photo Naomi Goldenson

When I decided to become a science writer, one of my goals was to combine two areas of science that can seem far apart: physics, which I got my degree in, and biology, ecology and the environment, which I also find fascinating and care a lot about. Stories that do this have been among my favorite to report and write, as well as among those that generate the most interest from readers. This year I wrote two stories about physics and cancer (coincidentally published on the same day)—one for Nature on a research program that some say has lost its ambition, and one for Inside Science on the perhaps surprising health legacy of the atomic bombs.My latest exploration of the physics-biology interface is a hot-off-the-presses Nature feature story on “active matter,” a new class of materials that are based on biological building blocks and behave surprisingly like living cells, despite not having DNA and other components that define life as we know it. As far as I can tell, this is the first feature-length story that has been written on this topic, but I’m sure it won’t be the last.

I continue to stay connected with the universities where I studied, writing for Johns Hopkins Magazine about an oncologist who made a surprising connection between genetics and lung disease, and for Wesleyan Magazine about a world-class kayaker-turned-educator and the director of the Joint Quantum Institute (just down the road from me at the University of Maryland).

Once in a while I even write a blog post! My last one was on the last day we got any real snow around here. It’s about winter and where I live.

If you’ve ever read a description of a writer’s life, you know that much of it is spent at a desk, doing glamorous things like deleting words and poring over notes to get the exact wording of a quote. I can confirm that such descriptions are basically accurate. That said, I did get to travel a lot for work this past year, including Boston (twice) for conferences, North Carolina (twice) for stories, Texas, as well as Washington state (see above) and Europe for pleasure and to visit friends and family. I also took my first international reporting trip, to the Yucatán peninsula in Mexico, funded by a grant from the Society for Environmental Journalists. I will have a story coming out later this spring on an effort to use the Yucatán’s carbon-dense tropical forests as a bulwark against climate change. While I was there I took the opportunity to visit the ruins at Calakmul, smack in the middle of Latin America’s largest protected forest reserve outside the Amazon!

Sweating in the rainforest, Calakmul, Mexico. Photo by me!


Reporting on the scene in Mexico! Photo Peter Ellis

Being president of the D.C. Science Writers Association has also kept me busy—sometimes a bit too busy. Since I took the post this past April, we’ve organized dozens of tours, workshops and social events, and launched a new website. And we have a big few months ahead, with a huge science writer party planned during the upcoming AAAS meeting in February as well as our annual Professional Development Day on April 2. (The D.C. Science Café mentioned above is also a DCSWA event.) It has been a real honor to lead this nearly 30-year-old organization, which is run entirely by hard-working volunteers, and I look forward to seeing it continue to thrive after I hand over the ceremonial duck (get it, Duck-swa?) to the next president in April.

I know these year-end messages are supposed to be all positive and chipper, and there is indeed a lot to celebrate over the past year. But it doesn’t feel right to not mention some of the challenges as well. On a personal level, while being a freelance writer comes with enviable freedom, it also comes with no small amount of isolation, job insecurity, rejected or ignored pitches, and time spent wondering if my ideas are any good. It’s easy to feel alone in this, until I talk to any other writer and am reminded that we’re actually all in it together. I would really like to spend more time with people and less time in front of my computer screen in 2016, so whether you’re a writer or not, please be in touch!

I also want to say something about the challenges that face science writing, as well as independent journalism more broadly. I won’t belabor the well-documented reasons for these challenges, except to say that from a business standpoint newspapers and magazines have adapted poorly to the Internet era, which is why you probably pay more for your cell phone service than for all your print and online subscriptions combined. Even though some publications are getting by—for now—on Internet ads or backing from moneyed foundations or benefactors, I believe that in the long run, journalism needs to be valued and sustained primarily by readers, listeners and viewers—in other words, by you and me. My plea to you is, when you’re considering how to spend your discretionary income, please support journalism as much as you can. Of course I have a special interest in science and environmental journalism, which I think is vastly underfunded, to the detriment of our democracy and our society. But many other important parts of our world are also hidden in shadows, and will continue to be unless journalists are able to shed light on them.

OK, stepping down from my soapbox now. I really do plan to send more updates this year. For one thing, I’m contemplating launching a new science/environmental journalistic venture, and if I decide it’s worth pursuing, I will certainly announce it. I will also send an update when the science café details are confirmed. Thank you for reading all the way through, and I hope 2016 is off to a good start for you!

geeseI live, I’ve come to realize, in a strange place—a forgotten pocket of inner-ring DC suburb, a sleepy suburb forever believing itself on the brink of becoming something else, but that may have already had its big moment, more than 200 years ago during the War of 1812, when the British army defeated the Americans and crossed a nearby bridge to reach Washington. The bridge goes over a river now so silted and shallow that an army could just wade across, a river of no commercial or navigational importance but of plenty of importance to geese, which congregate by the hundreds on its flood plain to talk and shit.

This river, the meek Anacostia, meanders between industrial rust and railroad tracks and restored wetland, wetland whose reedy grasses poke up next to a bike trail that promises connection to the nearby capital but instead dead ends at the state line. Trails and tracks. Tracks that separate too-clean wannabe-urban development from dirty auto shops and junkyards run by gap-toothed old men who tape vile, racist cartoons to the walls. Such relics hang on in a county that prides itself on being the wealthiest majority-minority county in the nation, indeed one of the wealthiest counties of any demography in the nation, yet forever a poor stepchild next to its gilded neighbors.

This is a place of paradoxes. The longer I live here the more confusing the paradoxes seem. Maybe it is a fitting place for me, also a paradox, the son of a Jewish father who teaches Holocaust studies and a German mother whose father had been drafted into the Nazi army. And raised in Kentucky, of all places, known for basketball and bourbon and tobacco and coal and none of the liberal ideals that fiercely inhabit me. And yet Kentucky is an inextricable part of me, at least in my discomfort in dense urban spaces and my wish for a bit of open ground to do as I please on.

On top of this mess the sky dumps a few inches of snow that sparkles white in the morning sun, and I dig my skis out of the basement and haul them down to the river, which is frozen over and covered in geese, and I ski along the levee, past white and black and brown parents pushing their children down the small hill on sleds—one activity that seemingly unites all people—and I follow the levee into one of our little parks, and turn onto a side trail, and suddenly I can almost forget that I live among dying industry and struggling suburb, and my skis cut sharp lines through flat snow disturbed so far only by deer hooves, and a shadow passes overhead and I look up to see a line of geese flying and calling. And I fall at the bottom of a small hill, because I ski badly (because no one grows up skiing in Kentucky), and I decide to lie in the snow for a bit even though I should be getting on with it because it is a weekday and I have things to do.

We have to steal these moments, I tell myself; we have to turn away from the pressing world and let ourselves be a little strange sometimes.

(Thanks, xkcd, for the geese.)

Photo by Phillip Sauerbeck

Photo by Phillip Sauerbeck

A version of this post was published February 20, 2014 on The Sieve.

I suspect no other relationship is more complex and fraught than that between humans and trees. I’ve been wanting for a long time to write something about it, but every time I try, I get overwhelmed. Where to begin?

For us humans, it indeed goes back to the beginning: Adam and Eve learned of their own humanity from a tree. Or if you prefer more scientific stories, our ancestors took a crucial step in speciating from other apes by descending from the trees. Since then we haven’t gone far from the tree, so to speak. We have eaten from trees, climbed trees, lived in trees, worshiped trees, studied trees, planted trees, hugged trees, and saved trees. We have also, at various times, cut trees down for fuel, for lumber, to make paper, to make weapons, to clear farmland, to create subdivisions, because they threatened our infrastructure, because we didn’t like where they were growing, and for no reason whatsoever.

After hundreds of thousands of years of shared history, have we and trees come to understand each other better? Three stories I have come across recently suggest the answer is, it’s still complicated.

A local tale

The first story is from my own neighborhood of Mount Rainier, a small city just northeast of Washington, DC in the watershed of a minor river called the Anacostia. The Anacostia River, which flows into the better-known Potomac, was once a commercially significant waterway. But as generations of people felled surrounding trees, bare soil eroded, silting up the water and reducing the clear-flowing river to a shallow muddy creek. One of the many things trees do for us—one of their ecosystem services, to use the fashionable term—is hold our land in place.

The Anacostia may be a trickle of its past self, but it can still flood. And as people have understood for a long time, when you deforest a watershed, rain washes more quickly into waterways, and flooding gets worse. Cities along the river responded to the elevated flood risk by building a levee.

Now, ostensibly to protect the levee, several hundred trees near a channelized tributary of the Anacostia going through Mount Rainier are about to be cut down. The byzantine reasoning is as follows: After Hurricane Katrina in 2005, the Army Corps of Engineers strengthened its requirements for levee certification, which is supposed to guarantee that a levee will stand up to a 100-year flood. People who want to insure property behind a levee have to buy flood insurance unless their levee is certified, so the Army Corps’ rules affect a lot of people. The new rules, in addition to raising the minimum levee height, require that trees growing within 15 feet of a levee be removed, because the Corps believes tree roots could compromise the levee’s integrity. This means that more than 200 trees in Mount Rainier, from small, scraggly things no one is likely to miss to 100-or-more-year-old sweetgums and tulip poplars, are destined for the chainsaw.

A view from the levee. The trees on the far side of the concrete wall are on the chopping block.

A view from the levee. The trees on the far side of the concrete wall are on the chopping block.

(Quick pause for disclosure: I am on Mount Rainier’s Tree Commission, which is advising the city on the levee issue. But all opinions expressed here are mine, and all the facts I’m reporting were presented at a public city council meeting. For a further perspective on the urban forest, check out council member Jesse Christopherson’s blog post.)

In the grand scheme, the number of sizable trees we stand to lose is small. And the county has agreed to give the city two new trees for every one that is cut down, so Mount Rainier could emerge in a few decades with more tree cover than it had before. But I’m struck by the perverse logic of the situation: People cause a problem (increased flooding) by cutting down trees and building in floodplains, and then pursue a technological solution that leads to cutting down more trees.

And for what? The new levee may protect against the current 100-year flood, but what about the 100-year flood 50 years from now, when climate change has loaded the dice in favor of stronger storms? We can’t keep building levees higher forever. A better strategy would be to reduce the peak flows that levees have to deal with, which would mean increasing tree cover and, perhaps, giving the river back some of its historic floodplain.

It’s unrealistic to hope tree cover will make a full comeback in an area as densely settled as the DC suburbs. But there’s plenty of room for improvement over the current 25 percent, the number reported by the Anacostia Watershed Society. The nearby city of Takoma Park, which has long protected its trees, stands out in satellite images for its dense foliage compared to neighboring areas. Other municipalities, including Mount Rainier, are now taking steps in that direction with laws that protect large trees on public and private land. Trees are our allies, and the loss of a healthy tree anywhere in the watershed makes all of us more vulnerable.

Tree-friendly Takoma Park, MD from the sky. From google maps.

Tree-friendly Takoma Park, MD from the sky. From google maps.

The global view

Flooding is a local problem, and the number of trees in the Anacostia watershed will probably always be of concern mostly to the people living in the watershed. But in another important sense, we are all united in our dependence on every tree everywhere. That is because trees store carbon in their tissues. This fact that was perhaps almost incidental until people began putting way too much fossilized carbon into the atmosphere; now, our collective future could depend on it. The world’s forests have become crucial reservoirs of carbon and sponges for some—though far from all—the carbon spewing from our cars and factories.

A new map made by a team of researchers at the University of Maryland gives us a global view of how well this global carbon sponge is working. Unfortunately, the picture, which combines over 650,000 satellite images, is troubling. Major areas of tree loss show up angry red both in tropical South America and the boreal forests of Alaska, Canada, and Russia. Things are more mixed in the U.S. South and Indonesia, and a few pockets of tree gain are sprinkled here and there. But the big picture, which the authors reported in Science, is that the world lost around 1.5 million square kilometers of forest between 2000 and 2012. As Peter Ellis, a forest carbon scientist at the Nature Conservancy (and incidentally a Mount Rainier neighbor) observes on his blog, “we are losing forests a lot faster than they can grow themselves.”

Credit: NASA Goddard, based on data from Hansen et al., 2013.

But there are reasons for hope. Forests in much of the U.S. have staged a major comeback in the past century, and are making small but significant dents in atmospheric carbon dioxide levels. And a recent study published in Nature showed that even old trees keep growing, soaking up more and more carbon the larger they get. Forests can buy us some time to deal with climate change before the worst impacts hit—but only if we leave trees standing.

The specter haunting this whole discussion is the possibility that if temperatures get warm enough, forests could start to release more carbon than they pack away. This could happen through increased respiration (in addition to consuming carbon, trees breathe out carbon dioxide just like we do) as well as increases in decomposition rates and forest fires. Forests as carbon sources would be an unmitigated global disaster, dramatically amplifying global warming and potentially making parts of the world simply hellish. Should this happen, the authors of another recent Nature article recommend that we harvest our forests and turn them into buildings and other structures that won’t decay and release their carbon. If we get to the point where we are cutting forests to save the climate, I don’t think I want to be around for it.

I find it wonderful that trees, which I love anyway, also store carbon, and have the potential to blunt the full impacts of our carbon pollution (though this borrowed time is worth nothing if we don’t use it to reduce that pollution as fast as possible). But I worry about the implications of viewing trees as big sticks of solid carbon—what one might call the widgetization of nature. The Nature authors manage to write a whole article about trees without mentioning a single actual species. That kind of abstract view makes it easy to imagine harvesting those trees if they become carbon sources, regardless of the other benefits they may confer to people or other living things. It’s a view that may see the forest, but misses the trees.

Losing a loved one

As anyone who has been to a forest knows, there is no such thing as a generic tree. There are only white oaks, sugar maples, pitch pines, and so on. And each tree is the basis of a unique food web, many of which contain organisms not yet known to science. Trees of different species are not interchangeable with each other, nor with other things we might discover that do an equally good job of holding carbon. We have only barely begun to learn how the system works. To paraphrase Aldo Leopold, this is not the time to be throwing pieces of the machine away because we think we don’t need them.

This brings me to my third story, in which a particular tree native to my part of the world is disappearing, not because anyone wants it to, but nevertheless for an entirely human-caused reason. As my friends and family know, I have become fairly obsessed with this tree, the eastern hemlock, or Tsuga canadensis. I point it out on hikes and turn branches over to look for the fluffy white egg sacs of the hemlock woolly adelgid. I have written about this invasive insect, which is destroying nearly all the hemlocks in the eastern U.S. The adelgid was apparently introduced to the U.S. in or around 1951, by accident, on a shipment of Japanese hemlocks to a Richmond, VA nursery (the insect is native to Asia and hemlock species there tolerate it just fine). That such a catastrophe could originate from so trivial an incident is part of what makes the whole thing so spooky.


Hemlocks lining a stream in western Maryland

Hemlock bark was once used to tan leather, but otherwise the tree has never been of much value economically. The wood splinters easily, and except up north, the tree lives mostly in river valleys where few people go. In terms of ecosystem services, the trees’ perpetual shade keeps trout streams cool, and its evergreen canopy captures rain and snow all year round. These are not trivial benefits, but they are not the kinds of impacts likely to inspire a national conservation movement. So it is hard to imagine cash-strapped governments spending a bunch of money to save a tree whose loss will cost few, if any, jobs. Indeed, as Richard Preston reported in 2007 in the New Yorker, governments pretty much haven’t.

But viewed another way, the costs if the hemlock disappears will be immense—literally incalculable. For what is the value of a species? A species lost is lost forever, so one could argue its value is infinite.

To be clear, the eastern hemlock itself is unlikely to go extinct, at least in the near future. Insecticides can protect individual trees if applied regularly, and winters in the upper Midwest and Canada, where many hemlocks live, are too cold for the adelgid to survive (though global warming could eventually remove that protection). But far more than the tree is at stake. Entomologist Louise Rieske-Kinney and her students at the University of Kentucky have studied the organisms living in hemlock-shaded valleys. The scientists have found that certain aquatic flies eat hemlock needles that fall into the streams. Certain spiders eat those flies, and fish eat those spiders. Removing the hemlock is like pulling the bottom block from a toy tower—the rest of the blocks come crashing down too.

Changes in streams may just be the beginning. Preston described in his article climbing (now-dead) hemlocks in North Carolina and seeing a whole world living just in the trees’ canopies. “There were small hummocks of aerial moss, spiderwebs, insects associated with hemlock habitat,” he wrote in 2007. “There were mites living in patches of moss and soil on the tree, many of which probably had never been classified by biologists. The hemlock forest consists in large part of an aerial region that remains a mystery, even as it is being swept into oblivion.”

A hemlock graveyard in Shenandoah National Park

A hemlock graveyard in Shenandoah National Park

Since 2007, scientists have shed some light on this mystery. Talbot Trotter, an ecologist with the U.S. Forest Service in Connecticut, told me he and his students have discovered hundreds of insects, mites, and spiders that seem to live on hemlock branches and nowhere else. The researchers would know more, except there is hardly anyone in the world with the expertise needed to classify the species they are finding.

Meanwhile, forest managers up and down the Appalachians lead small armies of insecticide sprayers into the woods. Their goal is to hold off the adelgid, at least from the largest and most visible trees, while biocontrol researchers try to breed and release an effective adelgid predator. But it is an uphill battle; predatory beetles that have been released often consume all the adelgids in a small area and then disappear. No one to my knowledge has gotten a permanent population established.

The extraordinary effort and care of these scientists and forest managers is the flip-side of the carelessness with which the adelgid was released onto this continent. Hundreds of people are now dedicating careers to understanding the insect and the hemlock, and to slowing—and perhaps eventually reversing—the damage. They’re not doing this because it pays well or because it’s glamorous work, or even because we as a society need the eastern hemlock. They’re doing it because they love this tree.

What mysterious forms live in the canopy?

A tale of survival

It’s not just the hemlocks that need love. The emerald ash borer is destroying the nation’s ashes. Asian longhorned beetles are attacking the great maple forests of the north. A fungal disease spread by a scale insect threatens the beech (another one of my favorites). The mountain pine beetle has brought down millions of pine trees out west and could do even more damage if it makes its way east. Already the American chestnut and American elm have largely succumbed to their own introduced pathogens. Invasive species amped up on climate change are doing what humans with their saws and axes could not—excising whole tree species from the landscape.

And yet, I suspect most trees will come through even this latest round of insults, as they have countless times before. The eastern hemlock was once far more abundant, but pollen studies show that it declined dramatically somewhere between five and six thousand years ago. No one quite knows why, but climate change and disease have been suggested. Still, the eastern hemlock is far from rare, and even in places where the adelgid has ravaged the older trees, new green shoots push their way up. Perhaps thousands of years from now, hemlocks will once again find conditions favorable and spread out over the land.

It is tempting to see trees as passive players in this drama, merely reacting to climate shifts, disease, and now humans and their invasives. But I have come to think of trees as playing the long game. They spread themselves far and wide, bank their seeds for decades or longer, and reproduce both sexually and asexually. For all the clear-cutting and species shlepping we have done on this continent, we have only driven two of its native tree species extinct in the wild, according to USDA plant geneticist Richard Olsen. (And at least one of these, Franklinia alatamaha, is still in wide cultivation). In short, trees know how to survive.

Yes, it’s not the trees I worry about. It’s the overconfident, impulsive, short-lived primates.

Writer’s note: this post was amended to reflect the fact that the Anacostia levee was not built in response to 1972’s Hurricane Agnes (it was actually constructed in the 1950s).

It’s cold tonight–really cold. So naturally I’m thinking about ice. Blackwater ice

Ice, as everyone learns early on, is the solid existence of water. It’s what happens when H2O molecules stop sliding and start sticking, when each negatively charged oxygen bonds distantly to one or more neighboring hydrogens. Ice has an unusual, airy crystal framework, less dense than its liquid form, and capable of endless permutations: snowflake, hailstone, glacier, iceberg, clinking cube in a martini glass, glassy sheet on a lake, crystalline cloud, icicle.

Liquid is water in motion: it falls, flows, gushes, seeps, swirls, sprays, wells up and sinks. It, like us, is restless, seeking. Ice too can fall, and flow, glacially. It heaves and cracks; it drifts and melts. But mostly, it rests – sometimes for hundreds, thousands of years.

Once, we too rested. The season for that was known as winter. Snow settled on the earth during this time, and we took our cues from it. The land couldn’t be worked and travel became difficult, so we Ice on the Patuxentstayed in, lay low, turned contemplative, read, made music, were quiet. Ice fishermen, it seems to me, still follow the logic of winter. They put a bucket on the ice, drill a hole, and sit.

Now we have abandoned our rest; our work knows no season. Electrons flow and combustion engines cycle with insensible constancy. Snow becomes a manageable inconvenience, to be shoveled aside or melted with salt. Planes are de-iced and fly; ships break through bergs. We keep moving.

The net result of all this motion may be to eventually rid the planet of ice. It has happened before. Fifty-six million years ago, during a strange period called the Paleocene-Eocene Thermal Maximum, the world was so warm that crocodiles wandered the poles. Sea levels were hundreds of feet higher. Of every million air molecules, perhaps two thousand were carbon dioxide (only 400 are now). We are a long way from an ice-free planet, but if we burn an appreciable fraction of our remaining fossil fuels reserves, we could get there.

What would that world be like? Polar bears, penguins, and many less charismatic species that also make their living on ice would go extinct. So would entire human cultures—the Inuits, for example, as well as the Lapplanders and native people of Siberia. Humans living in temperate places would lose many of the activities that give life meaning. Patuxent River partly frozen

The planet would also lose one of its ways to cool itself. Ice reflects nearly all the sunlight that hits it. Open water and land absorb much more of that light, and warm accordingly. This is what’s known as a positive climate feedback. Unfortunately, positive feedbacks seem to be much easier to find than negative ones.

Without polar ice, it has become clear, the planet’s climate would be unrecognizable. Atmospheric circulation is driven by the difference in temperature between a hot equator and frigid poles. The poles are warming much faster than the equator now. If the Arctic Ocean becomes the temperature of water off California’s coast, as it apparently was in the PETM, weather patterns would be very different. Already, some scientists believe the loss of Arctic sea ice is affecting the jet stream, which delivers rain to the temperate regions.

The paleoclimatic record is full of drastic regional climate shifts resulting from far smaller perturbations than a total loss of ice. During the last ice ages, for instance, positive feedbacks amplified variations in Earth’s orbit to send ice furling and unfurling across continents. Glaciers marched down into the lower 48 and the mid-Atlantic was covered in spruce forest. It’s worth noting that the average global temperature at this time was only a few degrees Celsius less than it is now. What will happen if we go a few degrees in the other direction?

I think about these things, but they are centuries off—though how many centuries is unclear, as polar ice keeps melting faster than expected. It’s safe to say that in my lifetime, we will continue to have winter scenewinter, though it may become a shadow of itself. If it does, I don’t think most people will mind. A recent New York Times story reported that Florida’s population is about to overtake New York’s, as both immigrants and internal migrants choose the sunshine state over its chiller cousin (apparently not minding that a significant part of Florida could be under water in a century). New York governor Andrew Cuomo petulantly said he prefers to have seasons.

I do too. I appreciate the variety of bodily sensations and experiences I get in a temperate climate. I like that I can ski in the winter and swim in the summer. I also feel I’m in a shrinking minority. In a world governed by the logic of motion, ice and snow have become problems that we figure out how to solve. We have become all too good at it.

(photos of winter in West Virginia, Maryland, and Washington, DC; all by the author)

A project named Climate Wisconsin made some beautiful videos of how climate change might affect life in that chilly state. Check them out.

This post originally appeared on The Sieve.

Life presents us all with certain problems, one of them being how to move ourselves from place to place. I submit that if you live in a compact, congested city, there’s really only one sane solution: ride a bicycle. Biking is carbon-neutral, it’s efficient, it’s outdoors, it’s exercise, it’s free, it’s fun. It’s a win-win-win-win-win-win.

But as I’m dodging morning traffic on my way to work in Washington, DC, I do find myself wondering, am I just crazy? Could the health benefits from bike commuting possibly outweigh the risk of getting flattened by some latte-swilling, texting SUV driver? And even if I avoid that fate, what about the longer-term effects of the exhaust fumes I’m sucking in with every breath?

Morning traffic into DC
Morning traffic on my ride into DC.

Since I am a science writer, I feel compelled to try to answer such questions with data. So it was troubling to find that one of the few sources providing data on the risks of different modes of transport puts biking near the top in deaths per journeys, miles traveled, or time spent in transit (apparently based on a 15-year old British survey). Only motorcycling, which is essentially bicycling at the speed of car traffic, proved more dangerous. U.S. data from a similar time period and cited in this paper tell a similar story.

While these statistics are sobering, I realize their relevance to me is unclear. For one thing, they may not reflect the recent upsurge in biking, which has started to make the activity safer in some places (more on this later). But more to the point, they don’t answer the question I really need answered, which is what is my personal level of risk, at my level of biking competence, when I ride along my typical routes?

Data to answer that question are starting to become available. Dave Love, a public health researcher at Johns Hopkins University, told me about a study in which he and his colleagues biked around Baltimore with cameras affixed to their helmets, and collected data on how close cars came to them. When Love and his colleagues were riding in bike lanes, cars maintained the minimum three-foot passing distance generally considered safe. On roads without bike lanes, however, cars often came closer than three feet when passing. Based on plenty of personal experience, I am not surprised.

Bike lanes are a good start, but bikers are even safer on cycle tracks or paths completely separated from roads, says Greg Billing, advocacy coordinator for the Washington Area Bicyclist Association. Fully separated bike networks are common in European cities like Amsterdam, where the cycling rate is much higher and crashes are relatively rare. Separated bike facilities are just catching on here; the cycle tracks on DC’s 15th and L Streets, for example, are great, as far as they go. But for most U.S. bike commuters, including me, a fully protected ride to work is not yet an option.

Bike researchers and advocates also talk about safety in numbers: the idea that one cyclist in a sea of car traffic is far more vulnerable than a school of cyclists pedaling together. Indeed, one of the benefits of cycle tracks is that they concentrate bikers along certain routes. Three to four hundred bikers per hour ride on DC’s 15th Street cycle track during rush hour, says Billing; nearby streets see far less bike traffic. Beyond the safety issue, I have also found that having a dedicated space is an empowering experience; for once I feel like I, as a biker, actually belong here, and am not just riding on someone else’s road.

A protected bike lane in New York City. (from Wikimedia Commons)
A protected bike lane in New York City. From Wikimedia Commons.

The benefits of bike infrastructure are just starting to show up in city-wide statistics in the U.S. In Minneapolis, which Bicycling Magazine has ranked as the top biking city in the country, the number of reported crashes has remained steady even as ridership roughly doubled. Portland, Oregon, another top biking city, has seen a similar decrease in the crash rate, though the total number of accidents is still increasing. Billing says that as of the last time DC released crash data, for the year 2011, the city didn’t quite have the ridership to bend the curve on the crash rate. But it’s getting close: the fraction of the city’s residents who commute by bike increased from 1.16% to 4.1% from 2005 to 2012.

Air pollution exposure, the effects of which accrue gradually, presents a totally different kind of health risk from accidents, which either cause injury or death or don’t. But the same measures that have been shown to bring down the crash rate can also protect bikers from toxic car exhaust or pollution resulting from brake and tire wear. For instance, bikers separated from cars by even a few feet will inhale far fewer toxic particles, says Audrey de Nazelle, an environmental health researcher at Imperial College London. Researchers in London found that the number of fine particulates in the air decreases substantially even between the side of a sidewalk closest to the road and the far side. And even if you don’t have access to a bike lane or cycle track, that’s no reason to get in your car, de Nazelle adds: most studies have found that the amount of pollution in the air surrounding drivers sitting in traffic is greater than that on the side of the road where bikers ride, though cyclists may inhale more pollution because they are breathing harder.

De Nazelle and others are now starting to do studies that get at the question I’m trying to answer. They have run computer models that compute how accident and disease rates would change in various cities if a certain fraction of the population switched from driving to biking. Researchers who ran such studies run in London, Barcelona and the Netherlands found that the health benefits bicyclists gain from doing aerobic exercise, in terms of reduced heart disease, stroke and so on, overwhelm any increase in accident- and pollution-related risks (see table 1 of this review paper). Unfortunately, similar results for U.S. cities so far seem to be lacking.

The gold standard for assessing health risks and benefits is a long-term longitudinal study, which follows a large group of people for long enough to see lifestyle choices reflected in disease and death statistics. Such research has been key in establishing, for example, that exercise reduces the risk of heart disease, and smoking increases it. But these studies are expensive and difficult to run, and are therefore rare, and the few that have been run have not looked at bicycling specifically, Love says. So for the foreseeable future, studies like de Nazelle’s, which project established risk and benefit factors onto specific behaviors like biking, may be what we have to go with.

I asked the researchers I spoke with whether they have changed their biking decisions based on what they’ve learned; they said they had. Love says he tries to avoid riding at night and in bad weather, when crash rates are higher. De Nazelle has changed her route choice to prioritize safety over efficiency. “I used to always choose the quickest routes; now I choose routes that I think will have fewer cars,” she says. De Nazelle also frequently bikes with her child, and she notes that her risk calculation changed when she had a passenger’s safety as well as her own to consider.

So, armed with data and expert opinion, I return to my original question—am I insane to bike right down a major DC commuting artery with no bike lane? I think the answer is, it’s complicated. On the one hand, I assume certain avoidable risks by placing my unprotected self in proximity to large, polluting fast-moving metal boxes controlled by people of varying competence and sanity. (And before I get accused of being anti-driver, I should confess that I also own and drive a car—sometimes *gulp* even down the same congested road I bike to work on).

On the other hand, by biking I efficiently solve not one but two problems—transportation and exercise—in a way that minimizes the environmental impact of both. I can partly reduce risk by riding defensively, wearing a helmet, and being aware of the places where accidents are most likely to occur—namely intersections. Possibly I could decrease my risk further by riding on less busy streets. But because the area where I live and ride–Prince George’s County and northeast DC–is underserved in terms of bike infrastructure relative to the rest of the region, any route that would keep me off busy roads would also add substantial time to my commute. And it can be hard to afford that time.

That’s my rationalization, but I have to admit I am also driven partly by stubborn idealism. I like to believe that if I assert my right to ride on city streets, others may be inspired to do the same. And if city planners see enough of us ditching our cars for bikes, they will eventually pay attention and build us a bike lane or cycle track, as the DC Department of Transportation long-term plan seems to imply. The more cities encourage biking and keep bikers safe, the cleaner, safer and more livable the urban environment becomes for all of us. Sometimes creating the future you want to live in means taking a bit of risk in the present.

What about you? What factors play into your decision to bike (or not bike) on certain streets?

This article was amended to reflect the fact that cyclists may inhale more air pollution than drivers because of their faster breathing rates. Most studies have found that the amount of pollution in the air surrounding drivers sitting in traffic is greater than that on the side of the road where bikers ride.