After all, shipping organic produce long-distance takes a toll on the environment, and at grocery stores,
it’s not always apparent just how far this organic lettuce or those pesticide-free apples have come. Head to
the store, and you’ll likely find produce identified only by country of origin—if at all. Meanwhile, locally produced foods have a growing appeal. Since 1994, the number of farmers’ markets in the US has increased 167 percent, as more people have realized that buying straight from the farm provides health, environmental, and economic benefits to their communities. But because locally grown food isn’t as accessible as organic at most grocery stores—and because it may be grown using conventional farming methods—which option is ultimately better?

Your health
When it comes to health, local produce has one major advantage over imported produce: Since local produce doesn’t have to travel far, it’s often fresher and more nutrient-rich than produce (including the organic kind) that has been shipped. Even under ideal transportation and storage conditions, produce loses many of its nutrients soon after being picked. For instance, according to a Penn State study, spinach kept at 39 degrees Fahrenheit (about the temperature of an average refrigerator) loses about fifty percent of its folate within eight days.

There’s another nutritional difference as well: Food picked for long-distance transport is often harvested while it’s green, before the nutrients present in ripe fruits are abundant. Smaller, local farms are more likely to wait until fruits and vegetables are ripe before harvesting. So fresher, in all likelihood, means more nutritious.

But locally grown foods are not necessarily organic, and conventional produce has its drawbacks. Just as I don’t want parabens in my hand lotions, phthalates in my perfume, or Bisphenol A in my canned tomatoes, it follows that I’m not too crazy about the idea of pesticide residue on my produce. Many pesticides are recognized carcinogens, and though the Environmental Protection Agency specifies levels that are safe for use, I have a hard time believing that “just a touch of poison” isn’t harmful, especially when listed effects include paralysis, cancer, and organ damage.

The environment
Locally grown food has a shorter distance to travel to market, and that makes an environmental difference as well. Unlike apples from New Zealand or grapes from Chile, produce grown regionally doesn’t need international
flights or the long-distance trucking system to get to its destination, so the carbon footprint of an apple can look more, well, like an apple, and less like the shadow of an airplane.

Local farms also preserve green space and limit suburban sprawl. Less sprawl means fewer commuters, lower carbon dioxide emissions, and cleaner air. More green space promotes a greater diversity of wildlife, offers migrating birds more rest stops, and is pretty nice to look at, too.

But even when it’s shipped from far away, organic produce provides environmental benefits for its home base: Because it is grown without pesticides, toxins are not circulated to groundwater, farm workers, and consumers.
Pesticide runoff kills fish and wildlife, gets into drinking water, and threatens the pollinators that are an integral part of agriculture.

The community
Locally grown produce plays a role in keeping our communities vital, and it is part of what makes the Bay Area and Northern California unique. After all, we have the rare privilege of being able to grow excellent food year-round, and we should celebrate by enjoying this bounty.

Purchasing locally is best when you can interact with someone from the farm, because these one-on-one interactions can help you find out how things are grown and let you make better buying and eating decisions.
Buying from local producers supports smaller farms and gives buyers a connection to where their food originates, a connection easily lost in the aisles of shiny waxed fruit at large grocery stores.

Buying from regional growers also supports the local economy, which seems extra important lately as small businesses struggle with the current economic crisis. According to a study published by the New Economics Foundation in London, food produced and sold locally infuses the local economy with about twice as much money as food brought in from far away.

The catch
If buying local is so great, why isn’t it the standard?

Well, for one thing, it’s not feasible everywhere and in all seasons. On a recent trip to Boston, I looked around at the snow-covered ground and across the frozen Charles River and realized that, in winter, eating locally can get pretty bleak. We’re all too used to the crunch of a fresh carrot to eat only seasonally available foods.

Another reason why you don’t see much locally grown food in chain grocery stores is the problem of scalability. While the large scale of industrial organic farming allows growers to work with companies that supply many stores, local production tends to be much smaller and more decentralized. It’s not as able to meet the large-scale demand of chain grocery stores’ ordering structure.

There are other issues to consider as well. Produce exports play a significant role in other nations’ economies—
for instance, in 2004 Chile exported $24 million worth of fruit to the US. And swearing off food that’s not grown locally would leave us with nothing more than vivid memories of pineapples and bananas.

The answer? Look locally
Even with its limitations, buying from local producers has a lot of appeal, and, at least to me, seems just as worthy a label to strive for as organic. For many people, embracing locavorism requires adjusting shopping habits, but when you add up the benefits, the extra effort makes sense. Luckily, there are plenty of options for people looking to localize, especially in the Bay Area. If you don’t already, head to your local farmers’ market, preferably a smaller one that has relationships with local farms, or head out of town to a nearby farm stand. If those aren’t available, think about joining a CSA, or Community Sponsored Agriculture program, which connects city dwellers with farms via a weekly box of fresh produce.

Encourage your local grocery stores, whether they’re chains or independent, to start stocking more local produce. Try to eat seasonally. If you’ve got a sunny spot in your yard, get up close and personal by growing some of your own fruits and vegetables.

Best of all, local produce often is organic. While a shift towards eating locally grown food may take a bit more effort and cost a little more, the benefits are clear. Eating locally may not work for everyone, everywhere, and all the time, but here in Northern California our soil, sun, and seasons give us abundant opportunities to savor the local flavor.

First, it helps to understand why solar installers are so crazy for unimpeded sunlight. Solar panels are made of individual photovoltaic cells grouped into columns. If one cell is shaded, production for that whole column shuts down. My brother-in-law Nathan Fleischer, a solar energy expert who spends his days figuring out the best placement for solar panels in schools, explained to me that if a branch casts a shadow along the bottom six inches of a solar panel, it will halt energy production for each column connected to those shaded cells. Even a little shade can have a big impact.

Weighing the benefits

Trees are famously good for the environment: they produce oxygen, create habitats for wildlife, filter noise, cool urban areas, slow soil erosion, reduce the run-off from heavy rains that can lead to municipal drainage issues and flooding, and break down pesticides and other groundwater pollutants into less dangerous compounds.

They’re also great for homeowners’ pocketbooks: planted close to a house, they will shade it from summer heat, reducing cooling costs. They provide shelter from winds in winter, lowering heating bills. The Center for Urban Forest Research estimates that after five years, a tree planted on the west side of a house will lower energy bills by three percent. After fifteen years, the savings rise to almost twelve percent. In short, when we plant trees, they repay us for our investment many times over.

Unlike trees, which take years to grow large enough to shade a house, solar panels start producing clean energy instantly. Manufacturing the panels uses energy from dirtier sources, but since the panels produce clean energy that emits no pollution or greenhouse gases, and use no fossil fuels, you compensate for that energy consumption pretty quickly. It takes between three and thirteen percent of the electricity generated over the lifetime of the solar panels to make up for energy used during their manufacture. That means you come out 87 to 97 percent ahead in the clean-electricity equation in the long run.

Solar power means clean energy not just for heating and cooling but for all of your energy needs, including lighting, cooking, and powering the television. It also directly reduces reliance on dirtier energy sources: for example, in PG&E’s 2007 retail customer electric power mix, 47 percent was derived from natural gas and four percent from coal. Solar power is already proving it can reduce dependence on such energy sources: according to CNN, last year solar panels on homes and businesses in California created as much energy as eight power plants.

What’s more, solar power gives back to the grid when demand is highest. Since it produces the most electricity during peak daylight hours, when energy is most expensive, it cuts bills and reduces the risk of rolling blackouts that can plague California summers.

Counting carbon

Both trees and solar power are celebrated as carbon dioxide management tools. Trees absorb carbon from the atmosphere and store it, creating a “bank” that’s cashed out only when the tree dies and decomposes. It’s hard to pinpoint the amount of carbon dioxide a tree can pull out of the air each year—it depends on its type and size—but estimates vary from sixteen to seventy pounds per mature tree. What’s more, by reducing the heating and cooling needs of homes, trees reduce the demand for energy from carbon dioxide-emitting fossil fuels.

But when it comes to carbon dioxide reduction, solar power really kicks bark. Current photovoltaic technology offers about twelve percent conversion efficiency, meaning it’s able to convert about that much of the solar rays it collects into electricity. At that level, it takes four years of the panels’ assumed thirty-year lifespan to pay back the energy it took to manufacture them, leaving 26 years of pollution and greenhouse gas-free electricity. Using US Department of Energy statistics, if the average American household produced half of its electricity with solar power, over the thirty-year lifespan, each home would keep 91 tons of carbon dioxide out of the atmosphere—plus half a ton of sulfur dioxide and nearly 650 pounds of nitrogen oxides.

Factoring in costs

Solar power may be more effective than trees in the fight against carbon dioxide, but it’s way more expensive. In some cases, trees don’t cost a thing: Utilities and organizations in cities around Northern California have programs offering free shade trees to residents. However, it takes years for trees to mature enough to provide the kind of shade that puts a dent in cooling and heating needs.

Solar costs are high, but credits, rebates, and subsidies make it more affordable. When I plugged in my location and average monthly electricity bill ($29) to the solar estimator at www.findsolar.com, I discovered that covering half of my electricity needs with solar panels would cost me $6,700 up front. The solar finder then calculated all the rebates and credits I’d be eligible for, including some from the state and federal governments and from Pacific Gas & Electric, and estimated that my total out-of-pocket cost would end up closer to $3,500.

Larger-scale production in the coming years will likely bring the cost of photovoltaics down, and some cities, including Berkeley and San Francisco, are looking into additional ways of making solar power more affordable for homeowners. There are also less expensive solar energy options, including solar heaters just for water, and thin film solar technologies, which need larger surface areas to make up for being less efficient, but are less expensive than photovoltaic solar panels.

No matter which you choose, it pays to make the effort. The US Forest Service estimates that mature trees add about ten percent to a property’s value, and you can bet that solar energy systems on houses are a selling point these days as well.

Balancing the choices

Do we really have to choose one or the other? In most cases, no. Select the right spot for new trees and solar panels, and you can have both while maximizing the benefits of each.

Trees do the most energy saving when they’re planted on the western and—to a slightly lesser extent—eastern sides of a house. (Shade trees on the southern side of a house increase the energy you’ll need for heating during the winter.) Solar panels, on the other hand, need a clear south and southwest path. So when it comes to location, trees and solar panels don’t need to clash. This doesn’t, of course, solve problems with shade from existing trees, but it does offer a clear set of guidelines for future planting.

When planting new trees, talk with your neighbors about your plans. Solar is on the upswing, and just because your neighbors don’t have solar panels on their roof right now doesn’t mean they won’t in five years. If your neighborhood has existing trees to work around, consider pole-mounted solar systems on sunnier parts of the property.

Also, choose your trees wisely. Deciduous trees help houses far more than evergreens because they allow warming light to reach the house in the chilly winter months. Likewise, trees with dense branch patterns aren’t as good as those with a looser, more open branching system. And even though big, long-lived trees offer a greater overall benefit when it comes to carbon storage, look for trees that, when fully grown, will be in scale with your neighborhood.

Finding solutions

So how did the battle between those South Bay neighbors end? The court ordered extensive trimming of two of the redwoods, but the controversy spurred a clarification of the California Solar Shade Act, which states that if the trees were there first, solar panel owners can’t force them to be trimmed or removed.

Finding that balance between trees, solar power, and neighbors in the coming years is going to be an issue that will mostly play out over the back fence, not in the courtroom, so it’s vital that we don’t start dividing into warring factions of tree huggers and solar purists. In the quest for a sustainable environment, let’s make the most of both, and do it alongside our neighbors.

But recently I’ve started to wonder if holding on to the old is really beneficial or just a knee-jerk reaction to over-consumption. In this new series of columns, I’ll explore the true environmental costs of objects throughout their lifecycles, from materials collection and product assembly, to the impact of use and beyond to disposal. Together we’ll see if newer is better as we pit products against one another to determine if one has a clear environmental edge.

There are plenty of places in my life where this quandary pops up, but only one of them racks up 10,000 miles each year. When it comes to your carbon footprint, is it better to keep driving the car you already have or buy a new hybrid?

Sure, it would be great if people drove less and bicycled or walked more, but our personal ecosystems are often just too big and time too short to give up the convenience of cars. While gasoline-electric hybrids are no longer the cutting-edge of eco-conscious automotive technology, they’re the most mainstream option. How would the Prius, that iconic hybrid, stack up against my own not-very-new four-door hatchback?

In a 2003 report, UC Davis Institute of Transportation Studies research scientist Mark Delucchi estimated that assembling a car—including turning its component materials into auto parts—produces about 1.8 pounds of carbon dioxide per pound of vehicle. According to Toyota, it takes about the same amount to produce a hybrid, which means that before it’s ever hit the road the Prius has already emitted about 5,220 pounds of greenhouse gas.

What about emissions from refining the gasoline itself? If you add the 19.4 pounds of carbon dioxide produced by burning a gallon of gas to the additional 5.1 pounds of “upstream” emissions Delucchi estimates are needed to make fuel, you’ve produced almost 25 pounds of carbon. That’s like dropping a giant Thanksgiving turkey onto the road every time you burn another gallon.

Armed with these numbers, I began my comparison. I drive about 10,000 miles per year. Since I don’t commute to work, that’s on the low side; the US Environmental Protection Agency puts the national average at about 12,500 miles per year, while Web site FuelEconomy.gov suggests 15,000 miles as an average. You can check how many miles per gallon (mpg) your car gets at FuelEconomy.gov; mine gets a disappointing 22. The 2008 Prius, on the other hand, gets 46. Each year, my car produces 5.56 tons of carbon dioxide to a Prius’ 2.66 tons. That’s a lot of turkeys. At this point as I did the calculation, a small voice in my head started contemplating a craigslist used-car ad.

But that isn’t the whole picture. Since I am considering replacing my existing car with one that must be newly produced, I need to know how long it would take to make up for the emissions involved in manufacturing the Prius—the equivalent of about eighteen tanks of gas. Since I drive 10,000 miles each year, it would take about eleven months for the emissions to balance out. (A person driving 15,000 miles per year in a typical passenger vehicle would reach that point in about six months.) And since I’d be using less gas, I’d be saving over $900 a year at the pump. The clear message: When it comes to emissions, mileage matters more than manufacturing.

How much would driving a Prius reduce my overall carbon footprint? Pinning down a national average is tough, but the EPA’s online carbon calculator sizes the typical footprint at around 10 tons per person each year, and driving makes up about six of those tons. The rest of the emissions come from heating, cooling, electricity, and waste. (The EPA doesn’t factor in air travel, though, and since a round trip cross-country flight emits a ton of carbon dioxide per passenger, that’s a serious omission.) Based on this estimate, a high-mileage vehicle such as a Prius would offer a thirty-four percent carbon footprint reduction after the initial manufacturing emissions recovery period. In my case, there would be a 5,809 pound difference each year, which, even including the manufacturing emissions, translates to an impressive 11.8 fewer tons of carbon dioxide over five years. That’s like erasing my carbon footprint for an entire year.

But we can’t decide yet, since carbon dioxide emissions aren’t the only factor. Tim Lipman at UC Berkeley’s Transportation Sustainability Research Center says that hybrids produce slightly more air pollution during the manufacturing process because of the smelting needed to make the sealed nickel-metal hydride batteries. However, he says that overall, hybrids pollute less since they require less gas and tend to be clean emitters.

There’s also the question of what happens to your old car. If you sell it, it will continue emitting the same amount of carbon dioxide while someone else drives it, so it’s hard to say whether that’s making things better or worse. Maybe your car gets better mileage than the one it’s replacing, or perhaps you’ve kept the new owner from buying a car that gets even worse mileage. On the other hand, perhaps it would be better to send your car to the scrap heap in the sky. These days, most cars don’t rust in the junkyard: more than 85 percent of each car is recycled, and as the recycling process improves, that figure is inching towards 100 percent.

Finally, there’s the financial issue: hybrids are priced at a premium. A new car is an investment no matter what, and with so many hybrids on the road today, there should be an influx of used models soon.

After crunching my way through the whole equation, it seems that in my case the impulse to conserve by making the most of what I’ve got doesn’t take into account vast differences in fuel efficiency. In California, where people drive more than 825 million miles each day, getting the most out of every gallon of gasoline has a tremendous environmental impact. That’s reason enough for me to take another look at consuming a little more in order to use a lot less.

Want to try this yourself? Here’s how to compare your car with a high-mileage vehicle:

1. Choose a hybrid or other high-mileage car for your comparison. Look up the weight of the car in pounds and multiply by 1.8 to estimate the pounds of carbon dioxide emitted during manufacturing.

2. Use FuelEconomy.gov to compare your existing vehicle against the hybrid. You can adjust the tool to reflect your annual mileage and highway-to-city ratio. Note the mpg of both vehicles. This website will give you an emissions estimate, but it doesn’t include the upstream emissions from producing the gas in the first place. We’ll do that in the next step.

3. Divide your annual mileage by the mpg. Multiply that number by 24.5 to determine the annual carbon dioxide emissions of each vehicle. Add the manufacturing emissions to the first year of the hybrid vehicle.

4. Calculate the emissions out over multiple years to assess the difference and determine the carbon footprint reduction.

Though I won’t be able to buy a hybrid tomorrow, this comparison has dramatically altered the way I think about driving. Great—not just good—mileage is far more important than I realized. Upgrading to a more fuel-efficient car has moved to the top of my personal to-do list, and with so many more high-mpg conventional cars and hybrids on the horizon, plus the promise of electric and plug-in hybrid vehicles, this is an exciting time to be considering a new car.

What’s more, thinking about those 25 pounds of carbon dioxide emitted for every gallon of gas I burn inspires me to leave the car at home—to bike, walk, and take public transportation more often, shrinking my footprint as I boost my footsteps.