The author of today’s post, Sheryl Canter, is an Online Writer and Editorial Manager for the Climate 411 blog.at Environmental Defense.

When it’s apple season here in New York and the green markets are overflowing, for a store to ship in apples from Washington State or New Zealand burns fuel for no good reason. Local food is fresher, tastes better, and supports the community. And locally produced food often results in lower greenhouse gas emissions - but not always. The greenhouse gas calculation is complicated, and you can’t assume that if a crop is produced locally, greenhouse gas emissions are lower.

For starters, the term "food mile" is itself problematic. A mile travelled by a large truck full of groceries is not the same as a mile travelled by a mini-van carrying a crate of carrots. A report published by DEFRA [PDF], Britain’s environment and farming ministry, says it’s more useful to think in terms of "food-vehicle miles" (the miles travelled by vehicles carrying food) and food-tonne miles (which considers the tonnage being carried).

The DEFRA report contains several counterintuitive findings:

• Trucking in tomatoes from Spain during the winter produces less greenhouse gas emissions than growing them in heated greenhouses in Britain.
• A shift towards local food systems might actually increase the number of food-vehicle miles travelled. This is because supermarket-based food systems have central distribution depots, short supply chains, and big full trucks. In local food systems, food is distributed in a larger number of smaller, less efficiently packed vehicles.

But the DEFRA report is not the last word on the subject. The Leopold Center for Sustainable Agriculture found different results in its 2001 study "Food, Fuel and Freeways." They reported that conventional food systems used 4 to 17 times more fuel and emitted 5 to 17 times more CO2 than local and regional food systems, depending on the system and truck type.

A Lincoln University study [PDF] included elements they called "factor inputs and externalities" in analyzing the impact of food miles - for example, the amount of water and fertilizer used, harvesting and storage techniques, means of transport, and dozens of other aspects of cultivation. They found that lamb raised on New Zealand’s lush pastures and shipped 11,000 miles by boat to Britain produced 1,520 pounds of CO2 per ton, while British lamb produced 6,280 pounds. The reason? British pastures provide poorer grazing, forcing farmers to use feed. They found similar results for dairy products and fruit.

There’s a push for "food miles" labeling in both the U.S. and Europe. North Carolina State University’s Center for Environmental Farming Systems is working with FoodLogiQ to develop a pilot program in North Carolina with an eye towards national implementation. Local food is fresher and supports the community, so a locale label can tell you that much. But "local" doesn’t necessarily mean lower greenhouse gas emissions. That depends largely on how the food is produced and transported. Just knowing where the food was produced doesn’t tell you that.

Read more posts on Environmental Defense’s Climate 411 blog.

Barbara Kingsolver's latest book, Animal, Vegetable, Miracle, tells the story of how she and her family lived for a year eating only food they grew themselves or that they purchased from local food-growers.

She was generous enough to take time from her book tour to answer our questions on the importance of keeping in mind that we are what we eat.

Why is buying and eating locally-grown food important?

The shorter the distance between your meal and its point of origin, the more you can know about it. Certain systems of oversight are meant to help you untangle the great unknowns of a complex system: "organically grown," for example, guarantees that a food item was produced without toxic chemicals. But it still may have accrued the same fuel costs of processing and long-distance transport as the conventional counterpart. And if there's profit to be made, corporate agriculture will be involved, with the likely agenda of watering down all standards.

"Locally grown," by contrast, is a designation that's incorruptible. Buying food from growers at small markets or through Community Supported Agriculture (CSAs) is really the only way for most of us to step away from a disordered food system. Food from your neighborhood will likely be whole, unprocessed vegetables, fruits, or animal products grown on small, diversified farms by growers committed to the health of their land. The food is good for you, and the money you spend on it stays in your community, helping to keep those nearby green spaces intact and strengthening your local food economy.

Environmental Defense is working to reform the nation's farm policies, which historically have helped agribusiness rather than family-run farms. What can individuals do to help keep farmers on the land?

We can start by thinking about farmers every time we eat. Our food, however it may have been altered in the interim, was grown somewhere, by someone. Who was it? How did that person use the land? How much of my food dollar went to a farmer, to help support sustainable choices? On average, 85 cents of every food dollar goes to the processors, packagers, advertisers and oil companies who profit handsomely from our lack of regard for soil, water, climate and the future. Farmers have no choice but to respond to consumer demand. They can only grow what we will buy.

Food policy is made, not born. It's not "natural" that organic and whole foods cost more than tallow-fried junk. We choose that through our tacit approval of the Farm Bill that defines food and nutrition policy in this country. We've elected to subsidize corporate commodity farms while leaving small, diversified fruit and vegetable farmers on their own, trying to compete. For organic farmers it's even worse – we make them pay for their own inspection and oversight. If we'd like to flip this over and subsidize healthy rather than unhealthy foods, we can call our legislators and start talking. This is a good time to do it, because the Farm Bill is being renegotiated at this moment.

The experiment chronicled in your book was a major family commitment. Did it change you as a family? How?

Commitment is exactly the right word for it, and that's what made the project valuable to us. For years we had been thinking about the food industry and our part in it. We tried to make choices that were better for the environment and our farmers – but mostly when those choices were pretty easy.

When we made a formal commitment to ourselves (and the world, via a book contract) to spend one year eating only fruits, vegetables, and animal products that were produced locally, it felt something like a marriage ceremony. It pushed us toward a fuller engagement with a way of life we really knew we wanted. It moved us to get to the farmers' market even on Saturday mornings when we didn't exactly feel like it. It helped us pass up the Peruvian asparagus and Bolivian bananas, concentrating instead on whatever wonderful things were coming into season in our own county. We learned to start with incredibly fresh ingredients and cook with the seasons. We learned to sleuth out local products at our supermarket, where we found organic dairy products, cider vinegar, and many other wonderful things produced here in our region. We spent more time as a family in the kitchen, and in the garden. Hoeing weeds is good exercise; inventing recipes is both scientifically and artistically creative; these things added up to time well spent. Our formal year-of-local has ended, but we're still eating locally because we enjoy it. We occasionally buy transported foods (usually something from the ocean) but we now consider that a splurge rather than a daily entitlement.

When my kids are my age, everything about food will be different except for one thing: they will still have to eat. The fuel-intensive food industry of the present, which has come to seem normal to us in recent decades, will become impossible. When people look back on this era, it will surely seem grotesquely indulgent. The next generation will have to return in some way to more local and sustainable food economies. I'm happy to participate in this part of my kids' education, giving them a genuine understanding of food processes. What could be more important?

You're a long-time supporter of Environmental Defense. Is there a particular message you would like to give our audience of online members and activists?

Your members already know, as I do, that Environmental Defense is an effective force for steering this country's environmental policies into a cleaner future. I can only offer individual encouragement, and the promise that small changes in our lives, multiplied by thousands, add up to a revolution. We can't wait for radical conservation measures to be imposed on us by our government – that takes a courage that our political system probably can never muster, no matter who's in charge. The way to look at it, I think, is that WE are in charge, individually and collectively. By proving to myself that my family can learn to live well with less, drastically reducing our food-miles and our carbon footprint, I'm giving myself the courage to require more responsibility from myself, my fellow citizens, and our government.

Thanks so much for your time.

Thank you and thanks to all the other Environmental Defense supporters out there

Looking for more environmentally themed books? Check out the Environmental Defense summer reading list.

By Timothy Fitzgerald, Environmental Defense fisheries scientist

Long the provender of imperial banquets and champagne tastes, beluga sturgeon caviar from the Caspian Sea has been called the Rolls Royce of caviar. But therein lies the problem. Likened to black gold and magic pearls, the eggs of the beluga sturgeon are so prized that this bony ancient fish, going back 200 million years to the age of dinosaurs, has been fished to near extinction in the Caspian Sea.

Although the eggs from beluga are considered the crème de la crème of caviars, the other wild sturgeon species inhabiting the Caspian and Black Seas are also highly sought after and similarly depleted: Russian sturgeon (the caviar is known as osetra) and Stellate (sevruga caviar). Enormous international demand for caviar has significantly depleted most wild sturgeon populations worldwide.

The United States banned the import of beluga caviar after listing the species under the U.S. Endangered Species Act in 2005. It also prohibits imports of sevruga and osetra. Any of these types of wild caviar sold in this country will be illegal or past their shelf life and thus risky to eat.

Farmed roe wins praise from chefs as a substitute for wild depleted species

But for those who crave this delicacy, farmed white sturgeon caviar or closely related paddlefish caviar is a delicious eco-friendly alternative and increasingly praised by chefs."Loyal consumers of osetra, sevruga or beluga caviar form the Caspian Sea may find, as one New York Times reporter has, that caviar from farm-raised white sturgeon rivals the best Russian osetra," note the authors in "One fish, Two Fish, Crawfish, Bluefish: the Smithsonian Sustainable Seafood Cookbook."

Farmed sturgeon eggs range in color from cream and gray, olive and gold, to black (the various colors represent different grades) and, like their wild cousins, are traditionally served with toast points, spooned atop blinis or eggs, or garnishing raw oysters. Not only is farmed caviar less expensive than its wild counterpart, consumers can rest assured that farming operations are relatively benign – they do not significantly pollute local waters or destroy critical habitat. Other ecologically sound choices are roe from wild salmon and rainbow trout.

Postscript: Problems remain for wild sturgeon caviar in the international arena

Is there hope for dwindling wild sturgeon populations in Eurasia? Unfortunately and inexplicably, earlier this month the Convention on International Trade in Endangered Species (CITES) reopened limited trade in wild beluga caviar, after shutting down trade last year because of concerns about overfishing, illegal poaching and ineffective management. Beluga in the wild has declined by 90 percent in the last 20 years, according to the conservation group Caviar Emptor.

The lifting of the CITES ban on exports makes no sense from a scientific or biological standpoint. Beluga sturgeon are slow-growing, late-maturing fish that can live up to 100 years and weigh more than 1,500 pounds, making them particularly susceptible to fishing pressure. The ban was in effect for only one year, hardly enough time for the species to rebound or show signs of recovery. That would take years of careful management and science-based limits on catches or a reprieve from fishing altogether.

In the meantime, Environmental Defense urges consumers to choose responsibly farmed caviar produced in the United States and Europe.

Editor's Note: We're happy to introduce another blog feature today, a bi-weekly column by Environmental Defense. Every two weeks, Online Activism & Outreach Coordinator Jessica Bosanko will bring you news, information and action items about ED's efforts to "find innovative, practical ways to solve the most urgent environmental problems."

By Timothy Fitzgerald, Environmental Defense scientist

Seafood lovers who want safe and eco-friendly fish might need help sorting through the mixed messages out there. The issue is complex – but here's how to sort through it why to choose healthy, sustainably caught or farmed fish.

Eating even modest amounts of fish helps protect against heart disease and is essential to the developing brains of fetuses and young children. The federal government and the American Heart Association both recommend two servings of seafood a week to reduce the risk of heart disease and death from heart attacks. The greatest cardiovascular benefits come from eating fish high in long chain omega-3 fatty acids, such as small oily species like herring, and mackerel, and larger predatory fish like salmon and some tuna.

Fish are disappearing from the oceans

Sadly, even as the health benefits of eating fish are becoming clearer, the ocean's ability to provide plentiful seafood is diminishing.

Since the 1950s, when industrial fishing began in earnest, large fish have mostly disappeared from the oceans, plummeting by an astonishing 90 percent according to a 2003 analysis. If we continue current fishing practices, most fisheries will be exhausted by mid-century, a recent report concluded. Many of America's favorite seafood – Atlantic cod, sea scallops, flounder, grouper, snapper and more – are already overfished.

At the same time, health-conscious consumers worry about fish with toxins such as mercury, dioxins or PCBs. To avoid too much mercury, children and women of child-bearing age should be careful about how much large fish they eat, such as swordfish and shark. Some farmed Atlantic salmon is also high in cancer-causing toxins like dioxins and PCBs.

(More on the health benefits of eating fish and sustainable fisheries [PDF])

So how can these complex tips be simpler?

Environmental Defense's Seafood Selector provides a list of best and worst choices for the ocean. It highlights fish that are heart-healthy (high in omega-3s) and those that are either high or low in contaminants. It includes advice on how many times it is safe to eat a particular fish each month.

Stay tuned for upcoming posts where I'll focus on the environmental and health aspects of specific seafood choices.