“All the grapes were ripening at once,” Wendy Cameron recalls of the harvest that was the wake-up call.

Cameron is head winemaker at Brown Brothers, one of Australia’s largest and oldest wine producers. In her 16 years there, Cameron had seen changes — hotter summers, harvest dates inching earlier. While heat waves aren’t unheard of in Australia, the one they had during the late summer of 2008 was unlike anything she’d ever seen: It was over 105 degrees for 10 days straight.

You can’t just leave ripe grapes on the vine — their sugars will get too high, yielding wines that are too alcoholic. Too much sun exposure can also affect flavor, and eventually grapes will begin to raisin. Everything had to be harvested at once, Cameron knew, but they only had so many employees. The winery was designed to handle a limited amount of production at a time. They didn’t have enough refrigerators. They didn’t have enough water. (Water prices had tripled over the past year.) Those were taxing, frightening days, and Cameron says they got through it pretty well, all things considered. But it made her wonder about the future of Australian wine and whether the vineyards would remain cool enough to survive.

Two years later, in 2010, Brown Brothers’ chief executive Ross Brown announced the purchase of a large vineyard in Tasmania, an island 150 miles off the southern coast of Australia. Long thought to be too cold to make quality wine, that too had been changing in recent years. “’We want to position ourselves to combat global warming,” Brown said at the time of the sale, a statement that garnered headlines — and upset many.

“I know Ross got some calls that were utterly scathing,” Cameron says. Others, especially others in the wine business who’d likewise seen the writing on the wall, praised his candor, albeit quietly. “People said, ‘Wow. I can’t believe you’ve done that, it’s so progressive and forward and good on you.’”

“Climate change isn’t a straight line,” Cameron says. “It goes up and down. There were a couple of years there where, certainly as an industry, we had a bit of a taste of what it might be like. The Brown Brothers have just celebrated their 125-year anniversary. My job is to give them the right information so we can be viable in another 125 years.”

The question is how difficult a task that will be, not only in Australia and other hotter wine-producing regions, like southern Italy, Spain, and California’s Central Valley, but throughout the wine world. A splashy, controversial study published last year by the Proceedings of the National Academy of Sciences found that in major wine-producing regions, the area suitable for viticulture — wine-grape growing — is threatened. By 2050, such terrain will decrease by between 19% and 62%, under a business-as-usual carbon emissions scenario, and between 25% and 73% if carbon emissions increase, which some argue is more likely. The U.S. government’s 2014 National Climate Assessment, which lays out in spectacular detail and no uncertain terms what our country should anticipate in terms of climate change, summarizes American wine’s situation thusly: “The area capable of consistently producing grapes required for the highest quality wines is projected to decline by more than 50% by late this century.”

The story of how wine will react to climate change is one small but telling piece of the larger one of how agriculture as a whole will endure. But researchers are looking at wine specifically because for this slow-moving, climate-sensitive industry, anticipating how to properly adapt will be a particular challenge.

You can’t just move Napa or Bordeaux a few hundred miles north. Even a small change in overall temperature, or increased instances of extreme weather, will throw wrenches into the hard-won understanding producers have of their grapes, land, and climate — and of how to coax from that combination the best possible beverage. It’s not all bad news: A changing climate means that colder regions like Tasmania — and England, Scandinavia, and British Columbia — now have shots at becoming major wine players like never before. Will these new wine regions actually be able to replace the ones that have been cultivated for decades and in some cases centuries? Or will fine wine be something we lose to climate change?

“We chose wine because it’s a canary in the coal mine,” says Rebecca Shaw, who co-authored the PNAS paper. Shaw is the associate vice president and senior lead scientist at the Environmental Defense Fund. She and her collaborators, most of them academics, sought to understand how agriculture at large will adapt to climate change. We’re chatting in a conference room in the EDF’s downtown San Francisco 28th-floor offices. The Bay Bridge looms in the window behind us, defogging itself over the course of our conversation.

On a map, the world’s wine regions are particular little bands that fall in between the 30th and 50th parallels, the majority in highly biodiverse Mediterranean climates. This is because, as crops go, quality wine grape vines are super finicky. They need a cold — but not too cold — winter. They need a mostly frost-free spring during which their buds can safely emerge. They need a long, sunny growing season and eventual temperatures that are fairly warm — but not so hot that the grapes will sunburn or ripen too quickly. They need a fluctuation between daytime and nighttime temperatures, which enable the development of compounds that eventually become the complex flavors in a fine wine. Wine grapes are prima donnas; you don’t give them exactly what they demand, they don’t perform. Complicating things further, there are many different kinds of wine grapes, called varietals, like chardonnay, merlot, or riesling, which are even more particular about where and under which conditions they’ll best grow. Go over a certain threshold of temperature? You can’t grow pinot noir. Go under? You can’t ripen cabernet sauvignon.

This fussiness also makes wine grapes especially useful for gathering data about weather: Each vine is like a remote sensor out in a field, and the behavior of wines across a region can paint a picture as to a given season’s weather. European vintners have been keeping records for about a thousand years, which is one way climatologists have learned about Europe’s historical climate, including the Little Ice Age that struck the continent between 200 and 700 years ago.

Figuring out which grapes perform best where is painstakingly slow: It takes five to seven years for a newly planted vineyard to begin producing grapes suitable for winemaking. It takes years more still before vines produce good or, with luck, great — or, with further luck, excellent — fruit. The best fine wine, and certainly the world’s most expensive wines, come from regions or even individual rows of vines that have been cultivated for so long, whose behaviors are so well understood, that extremely high-quality grapes — and therefore extremely high-quality wines — are more or less guaranteed. (Certain European wine regions are steeped in so much tradition they’re recognized by UNESCO as World Heritage Sites.) In Europe, the identity of a wine is so tied to a fixed place that the wines themselves are named after where they’re made: Chianti is from Chianti, Champagne from Champagne. (If Americans played by the same rules, we’d call Napa Valley wines Napas.)

Worldwide, winemakers aspire to create wines that best express the personality of a given area’s climate and weather, a concept called terroir, or the taste of the place. A given wine is thought of as an expression of a given geography’s climate; much the way that you can’t make New York bagels in Iowa, the idea is you can’t make a Burgundy anywhere but.

Shaw says that’s the other reason they chose to focus on wine — people care about where their wines originate. “No one cares about where their corn comes from, nobody cares about where their wheat comes from,” she says. Wine consumers — especially in America, where wine is often believed to be snobby, unapproachable, or expensive — tend to be conservative in their selections and have internalized the idea that some wines from some places are better bets than others. Chances are, even if you prefer boxed wine over bottled, you might scoff at a wine from New Jersey.

In their study, Shaw explains, they wanted to look at the extent to which the wine industry would have to move poleward — further south in the Southern Hemisphere, further north in the Northern Hemisphere — as a result of the changing climate, and then what the impact would be upon that movement on existent ecosystems. What is the potential conservation impact of vineyards being planted in Tasmania, or British Columbia, or England? Their paper specifically mentioned the potential effects upon a giant panda habitat in China and in the Yukon-Yellowstone corridor. “Bid adieu to Bordeaux, but also, quite possibly, a hello to Chateau Yellowstone,” the The Guardian quipped in response.

Shaw expresses frustration that many in the press were distracted by the detail in their report about the pandas and missed the bigger stakes. “One of the major focuses of our work is to feed the planet without killing it,” she says. “How does agriculture need to change? What are the incentives that need to be put in place that won’t undermine the long-term sustainability and don’t create more environmental harm?”

Wine isn’t actually food, though. Especially if we’re talking about fine wine, it’s a luxury.

“Wine is food to many cultures,” she responds, adding that most crops both deliver sustenance and are meaningful culturally. Corn is meaningful. Rice is meaningful. Humans have been cultivating wine for 8,000 years. “You can get into an argument about what’s food and what’s necessary and what’s not necessary,” she says. “The bottom line is wine is a very, very important part of many, many cultures.”

There’s a touch of emotion in her voice as she says this. We could live in a world without wine, of course, but would we want to?

This year has been one of the driest in California’s history, and on the radio, there’s no end to the talk about the low snowpack, the parched reservoirs, the depleted Sacramento and San Joaquin rivers. Though it’s late February, the hillsides are tawny, not green. When I drive to Wine Country, many are quick to offer their opinions that the drought isn’t caused by global warming. Strolling through his blocks of chardonnay, one grizzled grower in Sonoma, who declines to be interviewed when he learns my line of questioning, whistles dismissively, “I guess everybody has to do something.”

In Napa, I meet with David Graves, who co-owns a winery called Saintsbury. Graves and his business partner met while graduate students at UC Davis in the late ‘70s — Graves’ background is in biology — and have been making climate-sensitive pinot noir and chardonnay here since 1981. The vineyard is gorgeous in the misty morning; blackbirds alight above the rows.

He is jolly and peppers his speech with quotes and anecdotes and jokes. Steel tanks loom overhead and two dogs pace around a tennis ball by our feet. We’re talking about how grape growers and winemakers have to be risk-averse given that they get only a single shot each year to make do with what that year’s weather produced. “If I were going to culinary school, if my sauce curdles, it doesn’t cost a year’s wages to do it again,” he says.

He recalls once visiting a cousin who’s a brewer. His cousin excused himself for a moment — someone had added too much water to a batch of beer and rather than boil it down, elected to just throw it all out and start again. Graves laughs: “I said, ‘This is a dream!’”

It’s vital, in other words, that Graves understand what’s happening in his vineyard, which he says isn’t warming.

Some researchers, in particular a Southern Oregon University climatologist named Gregory Jones, argue that Napa has been experiencing overall increased temperatures. In the ’80s and early ’90s, long before there was scientific consensus concerning climate change, Jones was looking at the question of how it might affect wine-grape growing. (Jones had done his dissertation in Bordeaux, and his family owns a winery in Oregon.) “I didn’t think we really knew enough about the basics,” he explains over the phone.

To Jones, it wasn’t hard to see that warming had already been affecting wine: “If you go back to Burgundy 10 years ago or Germany 10 years ago, they’d have one good vintage in eight or nine or ten. It was because they were variable and much colder,” he says. “And today they have seven or eight or nine good vintages in 10.” This matches what he’s witnessed in Oregon: “In my region, 50 years ago it was difficult because there was too much frost and a longer growing season. Bingo — we can do it.” Another way to trace climate change’s effect on wine already, Jones argues, is the increased alcohol levels in wines around the world — warmer years mean more sugar in the berries, as they’re sometimes called, which means more alcohol in the wine. (Others would argue that it’s simply become fashionable to make more alcoholic wines.)

David Graves, convinced he hasn’t seen a warming trend, partnered with a climate researcher named Dan Cayan at University of California, San Diego, and a trade group called the Napa Valley Vintners, which represents about 400 of Napa’s wineries. The data they gathered was more localized than Jones’. Their study, which hasn’t been published in a peer-reviewed journal, found that the warming trend in most non-urban parts of Napa Valley over the last 60 to 80 years has been “significantly less” than what Jones had claimed. (I later ask Cayan about the fact that it hasn’t been published in a peer-reviewed journal. “That’s partly my own fault for being a slacker,” he says, adding that there is additional work they are doing, in terms of sourcing and then cleaning up the data they’re gathering.)

“I really, really don’t want to give aid and comfort to climate-change denialists,” Graves says. All they wanted to do was shrink the proverbial pixel size: “Let’s get the resolution so we’re not in a grid that’s a hundred kilometers by a hundred kilometers, we’re in a grid that’s five kilometers by five kilometers. And ultimately that really matters because that could be the difference between you growing pinot noir and syrah.”

Graves says, in fact, he’s seen a cooling trend in his vineyard in recent years; whether that’s a short-term thing, he doesn’t know. And it’s true that the world will not warm uniformly. Some areas will encounter colder temperatures, or wetter ones, or extreme weather like heat waves or hail. Ultimately the scariest thing for grape growers and wine makers is uncertainty or large variation year to year. Graves and the polite Napa Valley Vintners representative I sit down with later that day say they don’t plan to use the data they’ve collected to model Napa’s future; climate modeling is expensive.

But it’s also not hard to intuit why producers and the NVV might not want more press about how their $50 billion valley, the crown jewel of American wine, is screwed. What they seem to want is a little impossible: to acknowledge that climate change is real, but that somehow they will be unaffected. (And on some level, isn’t that what we all want?)

Gregory Jones thinks people are simply afraid of speaking publicly, lest they inspire backlash like Ross Brown did after his Tasmanian purchase: “I’ve had conversations with the biggest winemakers in Napa,” he says. “I don’t have conversations with them at their front door, I have conservations at their back door.”

Regardless, there is a generally split opinion between what researchers and what industry professionals are saying (or are willing to say). Many took issue with the PNAS estimate — a potential 25% to 73% loss — when it was a published and covered in the mainstream press. As pre-eminent wine writer Jancis Robinson says over email, “I think those proportions are way too high, but I have certainly witnessed considerable changes.”

Noah Diffenbaugh, a Stanford professor who studies climate and food security and who has published several papers about climate change’s effects on wine, says there are a few big things we can take away: “I’m confident that we’ll see increasing temperatures in the areas that are currently the high-value, high-quality growing regions.” He goes on, “I’m impressed with human ingenuity and the ability of humans to succeed in a variety of environments.”

Worldwide, grape growers and winemakers are already adapting, as they always have, to a given year or month or day’s varying demands and challenges. There are things they can do in the case of really hot weather. They’re managing canopies to increase air circulation around berries. They’re spraying vines with what’s basically wine-grape sunscreen. They’re in some cases going to turn to technology — remote sensors or drones to help monitor vineyards and use water resources more intelligently, or even cloud seeding to artificially create rain. In some cases, they are starting to replant vineyards to varietals that they anticipate will better handle the increased temperatures to come.

Many of the biggest players in American wine are starting to look into what their options will be as things worsen. One of the largest domestic producers, Constellation, has partnered with a research extension of the University of California system to identify less commonly known varietals that are more suitable to a hotter, drier climate, especially in California’s San Joaquin Valley, where much of our supermarket wine originates. There are rumors of others — the largest producer, Gallo, and another giant, Bronco, which sells two-buck Chuck — experimenting with varietal cultivation and genetic modification to the same end. (Neither company responded to interview requests.) Inexpensive mass-market wines are also going to be less susceptible to climate change because they’re already so loaded up with additives, like powdered tannins, a super-concentrated grape juice called Mega Purple that adds color, and what’s essentially liquified oak chips. (And bottles aren’t labeled with ingredients, meaning consumers are often unaware of whether their wines are natural or full of additives.) These wines are less about terroir and more about drinkability attained as cheaply as possible.

Throughout the world, some big producers are looking into and purchasing sites in cooler areas, as Brown Brothers did in Tasmania. J. Barrie Graham, a banker with experience in financing and advising Northern California wineries, says no one was thinking or talking about global warming seven or eight years ago when making long-term financial decisions. “I would say now it’s a very common discussion.”

For now, David Graves says he’s not doing anything significant to react to potential changes in climate in southern Napa: “In the 25-year time frame, I’m ready to say probably we’re not going to see a radical change.” He adds that there are other potential changes that could threaten Californian wine — first among them the scarcity of water, changing consumer tastes, and changes in immigration that will affect California wine’s primarily Hispanic labor force. He then sighs. “Beyond that, from, say, 2040 on? All bets are off.”

“I’m reminded of two things,” he says. “One is that Harry Truman famously said he wanted a one-armed economist so the economist couldn’t say ‘on the other hand.’” His loud laugh echoes through the high winery roof: “The other thing is what Keynes is reputed to have said: ‘In the long run we’re all dead.’”

Nowhere is the story of what is going to happen to viticulture if nothing is done to curb climate change more starkly painted than in Europe. Europe is the world capital of wine, home to France, Italy, and Spain, the world’s first three largest producers, respectively. (The U.S. is fourth.) Most — and some would argue all — of the world’s best wines are produced there. In many European nations, laws govern which varietals can be grown where, at what density vines can be planted, whether irrigation is allowed, whether the addition of sugar is allowed — it goes on and on. Additives? Out of the question. Such laws seek to protect regional products but may end up having the opposite effect.

A much-repeated example is that in Burgundy, France, growers grow pinot noir as their red grape. If pinot noir is no longer optimal in Burgundy, growers won’t be able to switch their vineyards over to different red grapes and sell them as anything but cheap table wines — forgoing the hundreds or thousands of dollars that fine Burgundies can fetch. “As one of my colleagues in Germany likes to say, ‘Europeans are growing grapes and making wine in a cage,’” Gregory Jones says.

Jean-Marc Touzard, economist and research director at the French National Institute for Agricultural Research, says they’ve observed the effects of climate change on wine since the 1980s. For example, “The vine matures faster because of higher temperatures. In Languedoc Roussillon, the harvest used to be in September, now it’s at the end of August.” Hotter, more compressed growing seasons have also affected the wines themselves — acidity is lower; sugar and therefore alcohol are higher. Flavor profiles are changing.

That said, Touzard argues that the laws are starting to evolve, offering the example that in some southern growing regions, they now allow irrigation — “under certain date restrictions” — something that before would have been unheard of in French wine. It’s of course debatable whether this change, which to an outsider may sound insignificant, is enough.

Two things are clear: In France and around the world, it’s going to be the small producers, the ones with fewer resources to purchase new vineyard sites, or replant, or survive a few bad years, that are at greatest risk. In Europe especially, these are sometimes single-man operations. They make a handicraft. A wine blogger I speak with, Bertrand Celce, travels to France (and elsewhere) discovering and documenting the efforts of such producers. He says some grape growers he’s encountering certainly are pessimistic. Wet conditions, for example, means an increased instance of disease, something such producers — who don’t use herbicides — have limited means to combat.

“The problem is they have to do more work,” Celse says. “They have smaller surfaces, but they tend to have little employment.” If the case study of American Prohibition serves as an example, the end result of global warming will be a wine scene that is more homogenous in terms of style, and owned by fewer, richer players. Eventually, when the best wines in the world become more scarce, the bottles remaining will become even more valuable, meaning fine wine will be even more of a luxury commodity than it already is.

And yet, in more northern parts of Europe, in countries that have never been viable for commercial viticulture — and perhaps have long envied their neighbors — some see an opportunity.

The fall day I visit Denbies Wine Estate, in Surrey, England, is comically beautiful: blue skies punctuated by clouds fluffy as sheep. The parking lot is full. I am made to follow a flock of mostly gray-haired, mostly British couples as they’re led into an octagonal movie theater where a loud video explains the winemaking process, then down a corridor past the winery itself. The guide is chirpy and her rather unnecessary-seeming headset malfunctions. At the end of the tour we are poured three wines and shepherded into a gift shop where the women browse tea towels and Christmas ornaments with furrowed brows and the men stand about with hands in pockets. What’s most remarkable, to me, aren’t the wines but the fact that this is the sort of bustling touristy affair I’d expect to find in Napa or Mendoza.

Victor Maguire is courteous and wry and leads me on a tour of the estate in a sputtering Land Rover. He’s worked at Denbies, which was founded in the late ’80s and is one of the largest vineyards in the country, for nearly a decade. While grapevines have been cultivated in England for a millennium, the practice has always been marginal, a cottage industry. The problem had always been it was a little too cold, a little too wet, for a consistently good crop.

But in the last few decades, England has witnessed something fairly spectacular: the first real emergence of a commercial wine culture. New wine regions often make their name on a particular wine or two, and England’s is sparkling wine. We are geographically not all so far from Champagne, and the soils here are very similar. Climate change means that England will become “increasingly more ideal than Champagne” for sparkling wine, Maguire says.

As numerous people in the English wine industry point out during my visit, sparkling wine was most likely invented here, in 1662. The producers of Champagne then began replicating the process, which they dubbed the méthode champenoise, or Champagne method. There is some perhaps perverse excitement, then, at notion that the French are at risk of losing their viticulture and the English might take up that mantle. (The English have wanted this for some time: When he financed his settlement at Jamestown, King James sent along French vignerons and required each homesteader to carry with him several cuttings of French wine grapes to plant, hoping his new colony would crush the French wine industry. This project failed, and the Virginians soon instead became all about tobacco.)

The day before, I visited a shop in London that sells only English spirits and wine — a whole wall of them. There are 400 vineyards in the country — though many fewer wineries — and perhaps more importantly, English producers are being recognized internationally for their quality: Four won gold medals at the International Wine Challenge this year. And indeed, some of the sparkling wines I tasted were superb.

As Maguire grips the Land Rover’s steering wheel and we wend through the rows, I ask him what he thinks of the possible effects of climate change on French wine. He pauses. “There is a school of thought that Champagne in 50 years will not have the ideal climate,” Maguire says judiciously, with a small smile. He then talks more freely about the hard weather France has seen of late. This year, for the third vintage in a row, for example, Burgundy lost a significant portion of its crop to hail, and the Languedoc was hit by the worst flooding in 60 years.

“It’s happening already, and we know that the continental growing and ripening seasons are becoming more compressed,” he says.

Harvest is underway at Denbies. We pass a group of laborers as they relax and lunch in the sunshine. But isn’t it a bad thing, I ask, if we lose French wine?

“I don’t think we’re losing France,” he replies. “I think they’ll have to learn to compensate.” He adds, “I think it’s great that English wine now has a place in the European arena.”

The problem, though, is that England or Tasmania is probably not going to be able to ever reach the level of output as the great traditional wine regions of the world. There’s the additional problem of styles. As wine writer Jancis Robinson points out to me, these newer regions “make completely different sorts of wine. Cool-climate wines are very different in style from those produced in the hot, dry regions under threat.” The latter produce larger-bodied reds. Most importantly, though, whereas the French or the Italians or the Spanish have been perfecting what they do for centuries — and wine is an integral part of each of those cultures — these new wine regions are in their relative infancies. People are still figuring out what works best and where, and that trial and error can take lifetimes.

If all of New York bagels were about to disappear forever, how much of a silver lining would it be if there were new opportunities for bagels in Des Moines? Especially if in this metaphor, there were bagel shops that had been perfecting their crafts for not just decades but in some cases centuries? This is the scariest part of global warming: the fact that we won’t be able to undo the damage done, that we won’t be able to extricate Venice, or New Orleans, from the sea. Their disappearance will be a net loss, regardless of what mountainside civilizations will someday rise.

Maybe we aren’t afraid enough. Or maybe we are too afraid. Maybe it’s just wine.

We turn another corner. Robust rows, their berries full and heavy, surround us. Maguire stomps his foot on the break and we lurch to a halt. His mouth falls open.

“The fruit looks spectacularly good!” he exclaims. “I’ve never seen it look so good!”

Marie Telling assisted with reporting in French.

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