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Coffee lovers of the world: Unite!

Over millennial time spans, plants have evolved remarkably effective techniques to deal with stress conditions they routinely encounter in their environment.
Take hepatica, for example, a tiny spring-flowering herb at home in Tennessee’s woods. When it senses frosts arriving, it loads its cells with sugars to act as antifreeze. As David Haskell says in “The forest unseen,” it also adds a purple pigment to its leaves, shielding these from sun damage when iced up. Hepatica thus manages to retain its leaves through the winter, growing new ones after the flower stalks have borne their lavender blossoms.
When the regularity of conditions in their environment changes, plants can suffer significantly. For some, far better known for their fruits than their floral beauty, this now appears to be happening.
As the “New Scientist” reported last year, the tree from whose bean fruit comes the world’s most favorite beverage — 1.6 billion cups every day — is threatened through conditions associated with the changing climate.
Evolved in high altitude, cloud-capped mountains in Ethiopia and cultivated since European colonization in similarly situated areas in Africa and Central America, coffee trees are “inordinately finicky” about temperature and seasonal rainfall. Building up their buds in dry weather, they need rain to trigger flowering. Too much or too long of rainfall, though, and the flowers don’t set fruit.
When temperatures rise, even by two degrees above the 18 to 21 degrees Celsius range in which the tree thrives, the berries develop too quickly, producing bland-tasting, poor-quality beans. Yields fall as temperatures rise more, and, if exposed to long periods above 30 degrees, the leaves drop and tumors appear on the stems. Adding to these problems an “evil weevil” pest, coffee bean borers, proliferate under warmer weather, producing multiple offspring generations in a year and marching up the mountains into new stands of Coffea arabica.
Under worst-scenario projections, the journal editors note, “almost all of the locations where the beans grow well will be unsuitable by 2080.” Already, under much milder temperature changes, coffee yields are at a 35-year low.
Vintners in France are experiencing similar, looming problems with the grapes that produce that country’s famous wines.
As a recent issue of “Der Spiegel” reports, grape growing, yet mildly affected in (coastal Atlantic) Bordeaux but now difficult in the lower Rhone valley, will soon be “over” altogether in its Mediterranean region if current climate-change trends continue.
Summer nights, the vintners say, are too warm to let grapes get their sleep. Unusually intense and more frequent heat waves and dry periods alternate with abnormally severe storms, leaving them to wither on the vine or, if swelling toward ripeness, be chopped to pieces by hailstones. Under steady warming, the ripening process is disrupted, the grapes’ sugars rising too early while natural tannins and aroma-boosting substances lag behind.
Though its beauty will be missed, hepatica’s demise would not cause starvation for people.
But possible loss of the beverages from grape and coffee plants, and the multi-billion dollar industries they support, might well jolt us into action to slay the climate-warming culprit.