Behind the Forecast: Climate vs Chocolate

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Behind the Forecast: Climate vs Chocolate
Cacao trees were first domesticated more than 1,500 years ago by Mayans living in what is currently Central America. (Source: Pixabay)

LOUISVILLE, KY (WAVE) - Chocolate. It makes us smile, it’s kinda healthy (depending on how much you eat) and is a big part of almost every major holiday. While we may have resolutions to put the sweets down this year, our planets changing climate may make that choice for us.

Cacao trees were first domesticated more than 1,500 years ago by Mayans living in what is currently Central America. The cacao tree, from which we get chocolate, can only grow in areas around 20 degrees north and south of the equator. The tree also needs very specific conditions to grow including uniform temperatures, plentiful rain, protection from the wind, high humidity and nitrogen-rich soil.

Science Behind the Forecast: Climate vs. Chocolate

Côte d’Ivoire, Ghana, and Indonesia produce most of the world’s chocolate. Rising temperatures on their own won’t make you involuntarily cut down on your chocolate consumption. Higher temperatures plus a lack of additional rainfall leads to the threat of increasing evapotranspiration. Evapotranspiration is defined by the NWS as the transfer of water from the earth’s surface to the atmosphere and comprises the sum of the processes of evaporation of moisture from the soil, water bodies, and wet vegetated canopies and the transpiration of moisture from plants.

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Evapotranspiration rate is driven by the amount of moisture available to evaporate and other meteorological factors. If everything else was the same, evapotranspiration would increase when there was more sunshine, higher winds, and increasing temperatures. It decreases as humidity increases; it will always be limited by the amount of moisture available.

Think of it this way. As temperatures rise they wring water out of cacao trees and without additional rain to supplement the water going into the atmosphere, the trees suffer.

Evapotranspiration is important not just for cacao trees in Africa and Indonesia but also for farmers and even golf courses right here at home. By checking a Forecast of Reference Crop Evapotranspiration (FRET) from the National Weather Service, those working in agriculture can see the depth of water that would evaporate and transpire from a reference crop under the forecast weather conditions on a daily and weekly basis. This helps irrigators figure out how much water is needed to sustain crops and golf courses. The warmer climate is also fostering another problem for cacao trees, bugs, and disease. Cocoa swollen shoot virus disease is spread by the tiny mealybug that feeds on the sap of the cacao tree.

While these factors may inhibit the growth of cacao trees in parts of Africa and Indonesia, all is not lost since other countries are still capable of growing the crop. For scientists to consider cocoa plants as possibly extinct, there would have to have been a complete absence of sightings of the plants for a minimum of 50 years. So don’t start stockpiling the chocolate just yet, that is unless you’re preparing for Valentine’s Day.

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