Wine, coffee and chocolate at risk: the climate doesn’t even spare our comfort food

Crops such as wine grapes, coffee and cocoa are not simply food products; they are economic and cultural pillars in many regions of the world. However, climate change—with rising temperatures, altered rainfall patterns and extreme weather events—is already threatening their quantity, quality and consistency, compromising the survival of small farms and plantations.

Faced with this scenario, climate intervention, such as stratospheric aerosol injection (SAI), has been proposed as a potential strategy to slow or reduce the rise in global surface temperatures. The concept is to inject highly reflective aerosols into the stratosphere, blocking some of the incoming sunlight. But this intervention, designed to mitigate warming, turns out to be a double-edged sword for the most demanding products of global agriculture.

Discontinuation of aerosols is not a guarantee

A recent study, published in Environmental Research Letters, compared two SAI simulation scenarios (ARISE-1.0 and ARISE-1.5), aimed at keeping global average surface temperatures close to 1.0°C or 1.5°C above pre-industrial levels. SAI, or injecting aerosols into the stratosphere to reflect some sunlight, is one of the most discussed geoengineering strategies. The ARISE-1.0 and ARISE-1.5 scenarios indicate two different levels of this intervention, designed to keep the global temperature around +1 °C or +1.5 °C compared to pre-industrial times. The analysis focused on the first ten years of production (2036-2045) following the hypothetical deployment of the SAI.

The main result is clear: the SAI scenarios analyzed fail to robustly preserve suitable growing conditions for luxury crops. Although the SAI stabilizes or reduces the temperature increase compared to the no-intervention scenario, the “suitability” condition for these crops is determined by a composite index that evaluates the combination of temperature, precipitation and humidity.

Luxury crops, unlike cereals often studied in relation to geoengineering, are extremely sensitive not only to heat, but also to changes in rainfall patterns and humidity.

Natural variability

The factor of greatest uncertainty was found to be natural climate variability. The simulations show a huge dispersion of results between different members of the ensemble. In other words, the outcome does not just depend on the intervention, but on the specific “climate achievement” that will occur. Although SAI may reduce the risk of extreme heat, this benefit may be offset by an increased risk of adverse conditions related to erratic precipitation or increased humidity.

Only in six of the eighteen regions examined do growth conditions uniformly improve across all climate realizations with SAI compared to the no-intervention scenario.

The case of wine grapes in Europe

In wine regions, SAI can have some positive effects, especially at lower latitudes. For example, in southern Spain, cooler temperatures due to SAI allow the chilling hours to be reached (chilling hours) necessary for the vine to break dormancy, conditions that may not be met in the no SAI scenario.

An unexpected result is that the probability of frost damage in spring was higher in the no SAI scenario (SSP2-4.5). Rising temperatures in this scenario bring forward bud break, making shoots more vulnerable to late frosts. SAI, by stabilizing temperatures, mitigates this risk.

Precipitation decides for coffee

The response of coffee in South America is also highly variable across space and among ensemble members. In key regions such as eastern Brazil, the SAI does not show a uniformly positive or negative signal. Frost and, above all, water availability indices have the greatest impact on suitability. A single frost event can wipe out a year’s production.

SAI can lead to increased precipitation, improving suitability based on the water supply index. However, strong internal variability means that SAI can either improve or worsen the frost situation.

Cocoa: humidity and the risk of disease

For cocoa, grown mainly in West Africa, the greatest influence is dictated by accumulated rainfall, which directly impacts the probability of fungal diseases such as pod black rot (black pod rot).

For example, in Cameroon, the ARISE-1.0 scenario shows a more robust signal of increasing eligible years. The maximum temperature index has no impact on the suitability of cocoa in West Africa under any of the SAI scenarios.

The economic implications

Research shows that geoengineering does not offer a reliable and uniform solution for luxury crops. Their complex ecosystems and sensitivity to variables such as precipitation and humidity mean that the net effect of SAI is highly variable and dependent on future climate realization. Assessing SAI requires analyzing a full range of possible outcomes and cannot be limited to just the average outcome. Few places in the world will experience uniformly beneficial or uniformly harmful growing conditions following SAI deployment.

This study raises a crucial question: are we ready to bet on the future of global economies and cultures with a tool with such uncertain and variable results?

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