How Climate Shapes the Wine World

Wine and climate share an intrinsic bond that begins with the location of vineyards and encompasses the choice of grape varieties planted, the annual ripening of the grapes, and ultimately manifests in the characteristics and styles of the wines crafted from them.

The grapevine requires warmth, water, sunlight, carbon dioxide, and nutrients. The ultimate goal of viticulture is to harvest quality grapes—healthy and ripe—suitable for winemaking. To achieve this, vines need to grow and develop through their vegetative cycle annually, necessitating five basic elements: heat, sunlight for photosynthesis, and nutrients from the soil. Among these, temperature is the most critical climatic element, as vines require a prolonged period of mild average temperatures to achieve grape maturity. This climatic requirement dictates the global distribution and localization of vineyards.

The major wine regions lie within two broad belts known as the Earth's Temperate Zones.

• One in the Northern Hemisphere stretches from the Arctic Circle to the Tropic of Cancer, with vineyards between 32º and 51º latitude.
• The other in the Southern Hemisphere spans from the Antarctic Circle to the Tropic of Capricorn, with vineyards between 28º and 42º latitude.

This uneven distribution of latitudes is mainly due to the disparity in land mass between the hemispheres.

Winegrowing and Temperature

Vine cultivation on the planet is intimately linked to heat. Within the Temperate Zone, various climates support viticulture, ranging from warmer to cooler, influenced primarily by latitude—the closer to the tropics, the warmer it gets—and geographical factors like water bodies and mountains. These climate variations dictate the distribution of different grape varieties, as each is typically limited to specific regions based on its ripening cycle. It's also essential not to overlook the impact of climate change on some wine regions. These factors greatly contribute to the diversity of wines produced globally.

Vineyards in cooler climates often yield some of the world's most prestigious and expensive wines. In these regions, grape ripening is a crucial annual factor. Varieties planted here generally have a shorter ripening cycle and mature earlier to avoid spring frost and the autumn rains and cold that can diminish or destroy a harvest. Typically, these climatic conditions favor white grape varieties. The vegetative cycles of selected varieties must align precisely with the climatic conditions to produce quality fruit. These regions are characterized by significant diurnal temperature variations. Terroir is highly significant in cooler climate zones as the most favorable locations ensure more reliable grape ripening over the years. Vineyards in these areas are usually smaller in size and less mechanized, leading to lower production and yields. Biodynamic and organic viticulture is more challenging to implement due to the risk of fungal diseases caused by humidity.

Occasionally, due to the annual climatic variability of cooler regions, grapes may not achieve full and proper ripening. These grapes will have lower sugar content, resulting in wines with lower alcohol levels and higher acidity, including more malic acid, and less phenolic maturity, which means tannins can be more pronounced and astringent. Cooler climate zones tend to produce more single-varietal wines. These wines are generally fresh, with a lower pH, and are mainly fruity, with minimal winemaking manipulation and limited use of new oak during aging. The more challenging years can yield a profile that seems less mature.

The white wines from cooler climates often exhibit high acidity and moderate alcohol levels. The dominant aromas are typically of green fruits and citrus, in addition to floral notes. They usually undergo minimal oenological manipulation during production and seldom use new oak. The red wines tend to have a lighter color, lower alcohol content with lighter body, higher acidity, and the risk of greener tannins. They often feature dominant aromas of fresh red fruits, floral and spicy notes, and aging aromas are not usually prominent. Producers in these regions often aim for finesse and elegance in the finished wine. The varying climatic conditions across years lead to wines heavily influenced by the vintage effect and are often sold at higher prices due to lower production. Many of the world's most prestigious and expensive wines are made in regions with cooler climates. A few sweet wines, mainly late-harvest but also some ice wines, are produced. The production of sparkling wines is more common in these areas since the grapes used do not require high sugar levels at the end of ripening.

Vineyards in warmer climates produce the largest annual volume of wine. In these regions, ripening is typically not an issue as the climate is more favorable and consistent year after year. The varieties planted often have a longer ripening cycle and mature later, thanks to mild autumns that do not pose problems with cold or rain at harvest. These varieties also need to be resistant to the heat and drought conditions they frequently face during the summer. These regions usually experience less diurnal temperature variation. Therefore, these climates are more suitable for planting red grape varieties. The climatic conditions allow for a better adaptation to the variety's cycle, so vineyards are more open to varieties chosen for their high yields. In these areas, terroir is less relevant as there are many locations offering optimal guaranteed ripening year after year. Vineyards in warmer climates are typically larger and more mechanized, which allows for greater production and higher yields. The main drawback of mechanized harvesting is that it reduces the possibilities for grape selection.

In warmer climates, the harvest is often delayed to achieve phenolic ripening of tannins and anthocyanins. This practice primarily results in higher sugar levels in grapes, leading to increased alcohol levels and decreased acidity in the finished wine, risking the production of flat wines with high pH. Warmer climates tend to produce more blended wines, using various oenological techniques and frequently aging in wood.

The white wines from warmer climates usually have higher alcohol levels and less acidity. The dominant aromas are often of riper and tropical fruits. The aromas produced by oenological techniques during vinification and the new oak used during aging often predominate. The red wines are typically deeper in color, with higher alcohol content, fuller body, lower acidity, and more mature tannins. They often have more manipulation during vinification, and producers tend to seek a fruity profile and potency in the finished wine. Extended aging can dominate the wine's final aromatic profile. Wines from these regions are less influenced by the vintage effect and are usually sold at lower prices due to higher production. The production of large volumes of bulk wine is common. Many sweet wines are produced, mainly using the drying technique, thanks to the high sugar levels the grapes can achieve.