Relish that coffee now. It might be extinct in 20 years.

Most people think there are two major kinds of coffee, arabica and robusta. (No doubt some people think the two kinds of coffee are regular and decaf, but I digress.) And it's true that almost all the coffee that you can find in the market, or at your local coffee shop, is made from one of these beans or from a blend of both.

Actually, there are 124 species of coffee. Unfortunately, as we learned in a new paper published last week in the journal Science, 60% of them are currently in danger of going extinct. The primary threats are habitat loss (caused by humans) and climate changes (also caused by humans).

Even though the term "endangered species" is more often used to refer to animals, we humans have already wiped out countless plant species, primarily through deforestation, and many more are going extinct each year. We will never know how many species have already been lost as we've chopped down rich rainforests to create grazing lands for cattle or monoculture plantations, but we do know that it's still going on.

Of the two major beans that we use for coffee, the better-tasting bean, arabica, is already endangered, according to the new study. Robusta coffees aren't bad, but as the new paper explains:

"Although robusta has some negative sensory qualities (e.g., tasting notes of wood and tobacco), it is favored in some instances for its taste, high caffeine content, and ability to add body to espresso and espresso-based coffees; it is now the species of choice for instant coffee."

If we don't do something to protect wild coffee species, we might soon be drinking nothing but robusta coffee.

If that seems implausible, recall that this already happened to the banana. In the mid-1900s, the entire worldwide production of bananas was basically wiped out by Panama disease, caused by a fungus. Before then, a tasty variety called Gros Michel was the dominant species, but thanks to the fungus:

"By 1960, the Gros Michel was essentially extinct and the banana industry nearly bankrupt. It was saved at the last minute by the Cavendish, a Chinese variety that had been considered something close to junk." (Source: NYTimes)

Now, the robusta bean is far better than "junk," but I for one prefer my arabica coffee.

The main threats to arabica (and robusta) are outbreaks of mold and fungal infections, not unlike the disease that wiped out bananas. Those 122 wild species–of which 60% are now endangered–are often resistant, allowing plant scientists to inter-breed the wild and domesticated varieties to create new strains that resist disease and taste just as good as the original. This wild "reservoir" of coffee is critical to saving coffee as we know and love it today.

You're probably accustomed to seeing coffee labelled by the region it's grown in, rather than the type of bean. This is similar to how we label wines as being from France, California, Australia, etc. Coffee is grown in many temperate regions, including Central and South America, Indonesia, central Africa, and Hawaii. Just as with wine, the climate makes a difference, but the bean itself is an even bigger factor. Consider the difference between cabernet, pinot noir, or sauvignon grapes for wine–in the same way, arabica bean coffees tastes quite different from robusta coffee.

If we don't pay attention to the threat to coffee, we might all be drinking a less-tasty brew in the years to come.

(Aside: I've been working for several years on a project to sequence Coffea arabica, the tetraploid genome of arabica coffee, and our results will likely be published soon. We're hoping that the genome will assist coffee scientists who are trying to breed new, disease-resistant varieties.)