There are more than 7 billion people living on this planet right now – 9 billion by the middle of the century, probably. Which gave us the title for the series we’ve been working on all this year about how to keep those mouths fed: "Food for 9 Billion" it's called. And we've looked at how to boost production without destroying the environment, how to deal with water shortages and how to slow population growth and cut down on waste. And yeah, sometimes questions like that can feel pretty abstract, especially at a time of year when it seems like all we do is eat. But as Jon Miller reports, we are part of the picture, too.
Reporter Jon Miller: If you look at all the challenges facing food producers around the world, you could argue that the most daunting one is climate change: higher temperatures, higher sea levels, crazy weather. Well, it turns out our food system isn’t just challenged by climate change – it’s also one of the biggest sources of greenhouse gas. Most of it comes from the production end – methane from cattle, nitrous oxide from fertilizer, CO2 from cutting down trees – but several recent studies have concluded that we will never be truly food-secure unless we change the way we eat – which is why I went to Baltimore.
Spike Gjerde: Union Mill is one of the mills that was built with native stone. So that's what you see here. These incredible old walls from the late 1800s ...
Reporter: That’s Spike Gjerde – G-J-E-R-D-E – in a coffeehouse he recently opened, called Artifact. Gjerde’s other restaurant, Woodberry Kitchen, has gotten national press for its seasonal, locally sourced food.
Gjerde: It's true that the entire focus and our commitment is to local direct sourcing of all of our ingredients.
Reporter: Also here today is Roni Neff. That’s N-E-F-F.
Roni Neff: And I am the research and policy director at the Center for a Livable Future at the Johns Hopkins Bloomberg School of Public Health.
Reporter: And an expert in the connection between climate change and diet. And I’m here because I’ve given Gjerde and Neff a challenge: to shop for and prepare a festive, not-so-expensive, not-so-hard-to-make, climate-friendly meal for a national radio audience.
I figured they’d have a menu worked out, but they don’t.
Neff: So can I ask what you have in mind?
Gjerde: Gonna see what’s in the market and, uh – I don’t have a lot in mind. Do you have any ideas?
Reporter: Gjerde says we’ve gotten used to having everything available all the time – like tomatoes in the winter, which he says make no sense in a place like Baltimore.
Gjerde: You have to be more flexible. Go to the market and see what's good.
Reporter (to Gjerde): I like making my decisions in the store.
Gjerde: Mm hmm.
Reporter (to Gjerde): I don't know whether that's the best way to go for tamping down our – the worst angels of our nature.
Gjerde: The ones that want tomatoes in February?
Reporter (to Gjerde): Yeah, tomatoes in February and Cap'n Crunch year-round.
Reporter: There is no Cap’n Crunch at the Belvedere Market. It’s like a mini indoor farmers market, with a café, a butcher, a fishmonger. Gjerde heads straight to the produce section.
Gjerde: He's got an amazing, beautiful kind of array of squash here. I think the – I think the blue hubbards, which are one of my favorite kind of all-around squash, were grown nearby in Pennsylvania.
Reporter: I know Gjerde’s big into local, but Neff is the expert on climate.
Neff: When something is produced locally, that doesn’t necessarily mean that it's going to have lower greenhouse gas emissions than something that’s produced farther away.
Reporter: That’s because a truck traveling 50 miles with a load of, say, apples can emit more greenhouse gas per apple than a ship carrying a huge load halfway around the world. But Neff says for most foods, transportation isn’t that big a part of the carbon footprint.
Neff: So it's not the first place we look when we want to make a change.
Reporter: That place would be meat. According to the Environmental Working Group, every pound of beef coughs up 27 pounds of greenhouse gas. Compare that to about 2 pounds for most fruits and vegetables. The difference adds up.
Neff: If a four-person family just cut out meat and cheese one day a week, it would be the same as taking their car off the road for five weeks. So it’s huge.
Reporter: Pork and poultry are better than beef and lamb. So, for the most part, is seafood.
Gjerde: So what we're looking at here are oysters. For us living in Baltimore and Maryland, around the Chesapeake Bay, farmed Chesapeake Bay oysters are one of the few things that are just almost as clearly a win for the environment, for our local food system, as there is.
Reporter: Oysters feed by filtering seawater, and they absorb carbon to make their shells. On the other hand, they need to be refrigerated, and it takes a lot of energy to move them around. Clearly, Maryland oysters make total sense in Baltimore in December. But how about Kansas City in July? The math can get complicated.
Neff: Consumers really need more information. A lot of it is just taking guesses and using our best judgment.
Reporter: Neff gives the oysters the thumbs-up. Gjerde grabs some kale, a few turnips, a couple of apples and a bottle of local wine. And, because he just can’t resist, a little chunk of bacon on the way out.
A friend of Gjerde’s is waiting for us when we get back to the cafe. He’s Ben Lambert, also a chef.
Gjerde: So I thought I'd invite him to come in and cook with us, kind of a little bit of a ringer.
Reporter (to Gjerde): Beautiful, bring a ringer in, absolutely.
Ben Lambert: OK.
Reporter (to Gjerde and Lambert): Cool.
Reporter: Lambert cuts the squash into oblong slices, drizzles them with oil and sticks them in the oven. Gjerde stirs a pot of barley with a little bit of the bacon for seasoning. I’m still not clear what we’re having for dinner.
Reporter (to Gjerde): You’re making this up as you go along, I think.
Reporter: Beyond some peels and stems, it’s a tidy kitchen. Roni Neff says a big part of climate-friendly eating is cutting down on waste.
Neff: We waste about 40 percent of the food that's produced. That's 1,400 calories per person per day. That is greenhouse gas emissions that never needed to have happened.
Reporter: That’s not counting all the extra food people like me eat just because it’s there.
Dinner’s ready in about an hour. The finished product is pretty impressive. We get a boat-shaped wedge of golden squash piled with barley, julienned apples and a sprinkling of greens. There’s also a little cylinder of kale that’s been squeezed and rolled and seasoned with garlic. Instead of lemon for the raw oysters, there’s a sauce made from minced red onion and sour grape juice from a local winery.
Neff: Oh, it’s so good. And I think this is exactly the point that was made, that you can eat climate-friendly and eat the best food in the world. It’s delicious.
Reporter: It is delicious – and festive, and not too expensive, and really not too hard to make. Granted, it’s a little hard to imagine all of America switching to squash and kale and turnips for the winter. But for tonight, I can say, we could do worse. In Baltimore, I’m Jon Miller for Marketplace.
Outro: “Food for 9 Billion” is a collaboration with Homelands Productions, PBS NewsHour and the Center for Investigative Reporting. You can see pictures of Jon’s meal and read tips on climate-friendly eating at marketplace.org.