Coffee's Last Drop? The Impact of Climate Change on the World Supply

Note to regular readers: you will notice that I’ve interrupted my current post sequence on how we got so politically polarized (which I will be resuming). This is partly for my own stress level (as the election race gets ever more strident!). And I want to give some attention to a pressing environmental issue (and not one that is frequently covered)…

That issue is…coffee! I don’t qualify as a true “addict” (certainly not in comparison to many of my erstwhile colleagues in the teaching profession!), but I do enjoy it! It will not be much of a surprise that a large majority of humanity shares that feeling (even though- surprisingly- American per capita consumption actually peaked in 1946!). Every morning, people drink an estimated 2.25 billion cups! It’s second only to oil as a resource industry, and second only to water itself as a beverage. And the demand is only growing (more on that later; Finland currently holds the per capita coffee title!). And that’s just the consumption side- the industry that feeds that humongous habit is worth at least $125 billion, and there are about 25 million coffee farmers in 70 countries (in the so-called “Coffee Belt”). At least 125 million people depend on coffee for their income; if one includes the entire coffee supply chain (from farmer to processors to shops and baristas), the estimate of those employed through coffee reaches as high as 800 million people (about 10% of the species!)

A fact that is just about as unsurprising as the ubiquity of coffee is the universal impact of climate change. In this post, I’ll be surveying the links between the two- how are the accelerating environmental changes, especially warming temperatures and ever-more extreme weather, impacting the growing of coffee? Turns out a lot of people (scientists, corporate heads, farmers, coffee drinkers, etc.) are very much invested in figuring out the answer to that question!

First- a short summary of the coffee plant and its history of human use. There are actually over 120 known wild species, all found in tropical Africa and Madagascar; they are rainforest understory plants, and vary in size from shrubs to small trees. But the coffee we drink is almost 100% from just two domesticated species: Coffea arabica (usually referred to as “Arabica”- a natural hybrid of two wild species), and Coffea canephora (known as “Robusta”). Roughly 60-70% of the beans consumed are Arabica, and it’s by far the oldest variety cultivated (the one considered to have the best flavor; hence the only type sold by Starbucks!). Its wild ancestor still grows in southwest Ethiopia, and it has been farmed and consumed at least since the 1400’s. That’s the point when coffee cultivation and use began to spread, starting with the Islamic world: first, just across the Red Sea from Ethiopia to Yemen, and (quickly!) north and west into the vast Ottoman (Turkish) Empire (the origin of that super-sweet & thick kind of coffee still called “Turkish” or “Greek”).

By the 1500’s, the coffee habit moved west into Christian Europe (thanks to those masters of commerce, the Venetians), and east to India. Thanks to European global colonization, coffee use (and production) then accelerated, to encompass just about all of the globe, from the 17th to mid-19th centuries (the Japanese also took to the drink immediately).

Back to the Arabica plant (a shrub in size). It’s a very picky plant, unfortunately. It needs: a tropical climate; nutrient-rich (preferably volcanic) soil; distinct seasons (as in “rainy” and “not-as-rainy”, often misnamed as “dry”); and a narrow temperature range (in Fahrenheit, about 59-68 degrees, which means it won’t grow in tropical lowlands like the Amazon). It therefore needs mountain slopes- more specifically at least at about 2,625 feet above sea level, but preferably higher, up to 5,000 feet. Even a change of half a degree in its temperature range makes a big difference. As said above, it’s now grown in many countries, but Arabica now comes almost entirely from Latin America (specifically the mountains of Colombia and Central America, and southern Brazil).

As the world population of coffee drinkers exploded, Europeans spread Arabica cultivation to just about all of the areas that suited the plant. If you know about the story of monoculture agriculture for all important crops, you can predict what happened next. The type of Arabica being planted was genetically identical everywhere. In 1869, farmers on the island of Ceylon (now called Sri Lanka) began to notice the rapid spread of a deadly coffee disease. It took the form of dusty orange spots on the leaves, followed by the death of those leaves and (inevitably) of the plant. It’s a fungus, known as coffee rust. It’s spread by wind, which carries its spores over great distances (even across oceans!). Within 20 years, Ceylon’s coffee industry was practically extinct (replaced by tea). Suddenly, Arabica everywhere, even before visible climate change, seemed headed for extinction.

Two things kept that from happening. The first was that scientists tackled the emergency. Research centers were set up in the major producing countries, but the scientific cutting edge has always been botanists at the Kew Gardens in London (at that point the center of the vast British Empire; Dr. Aaron Davis of Kew is the current world authority on coffee and climate change). These scientists came up with quite effective fungicides to kill the rust, and new varieties of Arabica that were not as vulnerable. Since Arabica is still the dominant form, it’s clear that they were quite successful. The problem is that the rust fungus keeps mutating (such that each new Arabica variant’s immunity is very short-lived). One author describes the situation (over the last century or so) as a “Red Queen” one (from the Lewis Carroll character who “has to run as hard as possible to stay in the same place”). Rust refuses to go away (it still causes $1-2 billion in damage per year!). But it did not cross from Africa to the top Arabica producer, Brazil, until 1970. Although it reached Central America in 1976, its main damage to Latin America didn’t come until very recently- in 2011-2014, when it devastated crops, especially in Colombia and Central America.

The rust fungus on coffee leaves (from npr.org)

The second response was to look for an entirely new form of the coffee plant. It turned out the best was one from the African Congo rainforest, Robusta. It would seem to be the ideal replacement in most ways: it grows well in hotter lowlands (72-86 degrees F.), and it’s quite resistant to most pests and diseases. It was immediately planted by colonizers in Southeast Asia. The one problem (and it’s a major one) is that it’s much more bitter than Arabica (though new variants have been producing a better flavor). As a result, it’s used today in two ways: in instant coffee (which took off in popularity after World War II), and as a cheap ingredient in coffee blends with the more expensive Arabica.

Another big coffee change has happened much more recently (starting in the 1990s)- a change in the mode of consumption that has dramatically increased the “coffee habit” worldwide. I’m talking, of course, about a certain Seattle chain, which has globalized the “coffee shop” as a social center and work space, as well as a place to try out ever more inventive personal coffee mixes.

Starbucks. It began in 1971 as one humble store in Seattle’s downtown market. But it didn’t take on its present magnitude until a certain Howard Schultz came along. Schultz was hired as director of marketing in 1982, and, on a business trip to Milan, had a transformational moment when he saw the Italian city’s lively “coffee culture” in its Piazza del Duomo, with people of every age drinking espresso in the numerous coffee bars. His thought was: “why couldn’t American cities have the same thing? And if they could, why couldn’t they serve coffee made with Starbucks-roasted beans?” He pitched that idea to his superiors and was rejected, such that he left the company in 1985 to open his own coffee shop. In 1987, he found enough investors such that he was able to buy Starbucks and reshape it to fulfill his vision. The rest of the story will be familiar; soon there were thousands of stores. The first one in Europe opened in 1998 (London), and in 2018 the story came full circle, when a Starbucks opened- in Milan!

The importance to this topic is that Starbucks (and the competition it has spawned) have dramatically increased coffee consumption as a public part of ordinary life (the British, for example, now drink more coffee than tea!). Right at the very moment that climate change has increasingly impacted coffee farming. Remember- Starbucks is proud of the fact that it only serves Arabica.

So- when did climate change start to have a serious effect? Scientists have known about the warming effect of humans’ steadily increasing emissions of gases from fossil fuels (especially carbon dioxide and methane) since the early 1960s. It now appears, given hindsight, that human-caused global warming, in its many (now all too familiar) forms (melting polar ice, sea level rise, more wildfires and extreme weather, etc.) seems to have set in in the 1970s.

Though no one to speak of (other than scientists) was discussing climate change in 1975, that’s when the first extreme weather event of modern times hit coffee- in one of the world’s major sources, southern Brazil. It was hit by exceptional cold in what has become known as the “Black Frost”- over 1.5 billion coffee plants died (half of all those in Brazil!!), and the world price of coffee doubled overnight! The result was that coffee farming in Brazil moved closer to the Equator.

Important non-climate events which affected the world coffee industry followed in the ‘80s (the decade of rising public awareness of climate change). In 1988, the Fairtrade movement began (tying global farming practices, including for coffee, to social justice through branding). In 1989, the International Coffee Agreement, which had stabilized the world price since 1962 through setting national production quotas, collapsed, when nations could no longer agree. Since then the price has fluctuated wildly- making the lives of coffee farmers, who, other than in Brazil, are overwhelmingly small producers living close to poverty, much more difficult. Additional disruption, suffering, and out-migration of coffee farmers came from bloody civil wars in the ‘80s- in Colombia, Guatemala, El Salvador, and Nicaragua (while most ended in the ‘90s, the war in Colombia lasted to 2016). On the other side of the world, the Communist government of Vietnam shifted the nation to a market economy in 1986, which led to a rapid expansion of coffee farming (making Vietnam the world leader in growing Robusta).

As global temperatures have continued to rise, the next big threat to coffee emerged by 2000, in the form of a tiny beetle- the coffee borer. It’s tiny- and it, uniquely among nonhuman species, likes caffeine (which is actually the plant’s toxin to deter predators!). It has bacteria in its gut which break down the caffeine and make it digestible. Borers apparently lived originally only in central African rainforests (location not known for sure). The female, which can fly, finds the fruit (“cherry”) and burrows all the way into the two beans, where it lays its eggs. The larvae then feed on both the beans and soft pulp. The result is that the beans lose all market value (the flavor is also ruined). Once the females have reached the center of each fruit, no insecticide will work. And as yet no effective method for using the borers’ predators (so-called “bioremediation”) has been found.

Adult coffee borer beetle- inside an immature coffee bean (size comparison!)- perfectdailygrind.com

What has happened with the warming of climate change is that the borers can now survive higher up mountain slopes- right in the range of Arabica farms! Presented with a huge feast, the beetles can now produce up to 5 generations in a single growing season! Borers are now found in almost all coffee-producing countries (in 2010, somehow, they even reached Hawaii, far out in the Pacific!). They are now doing billions of dollars of damage each year. Only two things seem to work for now: 1- raising the coffee under shade trees (that’s the “shade-grown” so much advertised, which benefits the environment as a whole by preserving forest cover and associated wildlife). The beetles seem to slow down somewhat if the plants aren’t in direct sun. And chemicals can still be used on them- if the farmer acts fast enough before the beetles have bored all the way inside.

So- to sum up- what are the current threats, especially environmental, to coffee, and what are the potential solutions? As explained, Arabica, the world's preference and the variety most constrained by temperature range, rainfall and seasonality, is under particular threat. The scientific consensus can be described as a "2050 apocalypse"! Meaning that the area of Arabica production could be cut in half by then, if present warming (and drying) trends continue! That's assuming an average increase of 2-2.5 degrees C. (3.8-4.5 F.). If the world warms by 3 degrees C., the prospects get much worse. How does warming hurt the plant? Not only does it boost damage from pests and diseases (which climb further up the slopes)- it wilts the flowers (that produce the beans) and stunts growth, dramatically cutting productivity (and damaging the taste). Arabica also needs a LOT of water- about 5 feet a growing season, or 39 gallons to produce a single cup! Yet extreme rainfall (including from hurricanes) is also a present danger. A different kind of threat is that to coffee biodiversity. Most of the 124 known wild species haven't been studied, and just about all (especially in the heartland for wild kinds in southwest Ethiopia) are threatened by deforestation (as well as by climate change). Add to that- like many tropical plants, coffee seeds can't be preserved for seed banks by the common freeze-drying process. The threat to coffee has big indirect implications, beyond for the drink itself; farming it has always been challenging and labor-intensive (though it has been one of the tropical world's most profitable crops). Already many young people in poor nations, especially in Central America, are deciding that making a living by coffee farming is now verging on the impossible, and are moving- adding to the unprecedented numbers of displaced people worldwide, including those who are trying to get into the United States.

So- is there any good news- please?? Yes. Scientists (including those employed by Starbucks) are evaluating, and planting, new resistant varieties. That includes two for Arabica (castillo and geisha). Robusta still seems to be holding up well to heat, pests and diseases (its main threat comes from irregular rainfall and unstable seasonal temperatures). Another species that was cultivated in the late 1800's, Liberica excelsa, is being brought back on a small scale (especially in the Philippines). It's a much larger (tree-sized) plant. It produces a large bean that is harder to process, and, while there have been improvements, doesn't yet match Arabica in flavor. Finally, an expedition to West Africa led by Dr. Aaron Davis has recently found a few remaining wild plants of a promising new species, Coffea stenophylla. The entire genome of Arabica has now been established, and is open-source, so now the world's scientists can investigate genetic engineering.

Another avenue that is just starting to be explored is expanding the area of coffee cultivation into the world's temperate zones (as they too warm). So far, there's been some success in two places (southern California and Sicily).

Of course, as for all climate change issues, the best solution, by far, is a dramatic worldwide reduction of greenhouse emissions! Coffee, also of course, is not the only important plant for humans at risk- just about all, including the basic grains of our diet (rice, corn, and wheat) are facing their own issues. Coffee will still be available for the near future; but let's not delay until it's too late!

That's all for this post- hope you found it interesting! You can expect to hear from me on another history topic sometime in the near future...

Resources:

As mentioned, Dr. Aaron Davis of Kew is the current authority on this topic; he’s quoted in many articles, and interviews can be found on YouTube.

Charles, Dan. “Exploring Coffee's Past To Rescue Its Future.” (https://www.npr.org/sections/thesalt/2013/04/26/178865467/exploring-coffees-past-to-rescue-its-future)

Davis, Aaron. “Can we create a climate-resistant coffee in time?” (https://www.theguardian.com/science/audio/2021/apr/27/can-we-create-a-climate-resistant-coffee-in-time-podcast)

Gattuso, Reina. “Solved: The Mysterious Origins of Your Coffee’s Worst Nightmare.” (https://www.atlasobscura.com/articles/what-kills-coffee-plants) Oct. 24, 2019. Coffee berry borer.

Jaramillo, Juliana; Eric Muchugu, Fernando E. Vega, Aaron Davis, Christian Borgemeister, and Adenirin Chabi-Olaye. “Some Like It Hot: The Influence and Implications of Climate Change on Coffee Berry Borer (Hypothenemus hampei) and Coffee Production in East Africa.” PLoS ONE 6(9): e24528. (https://doi.org/10.1371/journal.pone.0024528)

Marshall, Colin. “The first Starbucks coffee shop, Seattle - a history of cities in 50 buildings, day 36”, The Guardian (www.theguardian.com/cities/2015/may/14/the-first-starbucks-coffee-shop-seattle-a-history-of-cities-in-50-buildings-day-36)

McCook, Stuart, and John Vandermeer. “Rust and the Red Queen: Long-Term Perspectives on Coffee Rust Research."

(https://apsjournals.apsnet.org/doi/pdf/10.1094/PHYTO-04-15-0085-RVW), May 24, 2015.

McKenna, Maryn. “Coffee Rust is Going to Ruin Your Morning,” The Atlantic (https://www.theatlantic.com/science/archive/2020/09/coffee-rust/616358/)

Nittle, Nadra. “Eco-friendly, lab-grown coffee is on the way, but it comes with a catch,” The Guardian

(https://www.theguardian.com/environment/2021/oct/16/lab-grown-coffee-eco-friendly)

Pendergrast, Mark. “Uncommon Grounds: The History of Coffee and How It Transformed Our World.” (2019)

Scott, Michon. “Climate & Coffee.” (https://www.climate.gov/news-features/climate-and/climate-coffee)

Slavin, Terry. “The Brazilian farmers who are trying to keep the world in its coffee habit despite climate change” (https://www.reuters.com/sustainability/land-use-biodiversity/brazilian-farmers-who-are-trying-keep-world-its-coffee-habit-despite-climate-2024-09-16/)

"List of countries by coffee production," Wikipedia.org