Climate zones ex Klöppen-Geiger: 1 = Tropical rainforest climate, 2 = Savannah climate, 3 = Steppe climate, 4 = Desert climate, 5 = Etesian climate, 6 = Most humid temperate climate, 7 = Sinic climate, 8 = Humid continental climate, 9 = Transbaikalian climate, 10 = Summer dry cold climate, 11 = Tundra climate, 12 = Ice climate
Climate factors
The climate characteristics result from many factors such as exposure (solar radiation), precipitation, temperature, humidity and wind as well as their sequence and interaction. In addition to the soil type, the grape variety planted there and the individual type of winemaking, the climate is a decisive factor for wine quality. However, the very specific climatic conditions for a small area in which the vineyard is located (microclimate, site climate) and even smaller-scale conditions (microclimate) also play an important role. The vine thrives best in warm, temperate zones of the northern and southern hemisphere, the so-called vine belts. These are the relatively narrow areas between 40 and 50 degrees latitude in the northern hemisphere and between 30 and 40 degrees latitude in the southern hemisphere.
Conditions for the grapevine
Above all, the vine needs warmth and light. According to studies by the Geisenheim Research Centre, the optimum temperature for growth is between 25 and 28 °Celsius. This is largely determined by the altitude. As a rule of thumb, it drops by 0.6 °Celsius for every 100 metres difference in altitude. A hillside location is ideal in terms of vertical sunlight. The thermals are also favourable, as the cold air currents fall down the slope at night, where they warm up in the morning and move back up again during the day.
This is particularly important for quality white wines in terms of acidity. The tops of hills are planted with trees to slow down the flow of cold air, which in Europe is mainly used in Germany, Austria and France. Water bodies (rivers, lakes, seas) have a positive influence on viticulture because they reflect the light. It is no coincidence that many of the world's most important wine-growing regions are located near bodies of water.
The most northerly vineyards for quality wine cultivation are in Germany (51st parallel) and England (52nd parallel). The southernmost wine-growing borders are located at the Cape in South Africa (35° latitude), in Argentina and Chile, as well as on the southern main island of New Zealand (40° latitude). From the equator to 20 degrees north and south latitude, there is no viticulture due to tropical conditions with heat and drought, or only in higher areas up to 2,000 metres above sea level, for example in Kenya on the east coast of Africa. Outside of these areas, there is too little sunlight and precipitation or the risk of cold and frost. The suitability of a region for quality viticulture is described under Viticultural suitability.
Influence of the climate on viticulture
The first scientific investigation into the influence of climate on viticulture was carried out by the Swiss botanist Augustin Pyrame de Candolle (1806-1893) in the middle of the 19th century. The US researchers Albert Julius Winkler (1894-1989) Maynard A. Amerine (1911-1998) from the University of California used these findings. In 1944, they introduced the degree-day summation system, which categorises California into a total of five climate zones.
In the meantime, various climate classification systems have been developed worldwide on this basis. Various criteria are measured in the annual vegetation cycle of the vine or for the entire year and used for the assessment. These are temperature values, number of hours of sunshine and amount of precipitation.
The optimum temperatures for viticulture are between 25 and 28 °C during the ripening period if there is a sufficient supply of nutrients, good irrigation and sunlight. This is when photosynthesis reaches its optimum performance. The ideal annual average is 1,300 to 1,600 hours of sunshine, i.e. around 180 days with seven to nine hours a day. Based on the measured temperature totals (heat totals), the most suitable grape varieties are selected and the optimum time for harvesting physiologically ripe grapes is determined.
The suitability of an area for viticulture is also measured according to the average temperature of the annual vegetation cycle or that of the warmest month. With the "MJT" (mean January temperature - July in the northern hemisphere), a comparative indicator was created in Australia. Rainfall should be at least 300 millimetres from May to October (November to April in the southern hemisphere), with spring precipitation being particularly important due to shoot growth. Fungal diseases such as powdery mildew, downy mildew and botrytis are favoured with higher amounts. The climate within a year can affect the quality of the wine over a large area, resulting in good or less good vintages in larger areas.
In precision viticulture, scientific methods are used to take certain climatic conditions into account when cultivating vineyards. From the mid-1990s, cool climate winegrowing, i.e. planting vines at higher altitudes with continental climatic conditions, became popular.
Climate zones
A rough categorisation into large climatic regions is based, among other things, on the average annual temperatures. These have risen to an alarming extent over the last 50 years. The warming trend from 1956 to 2005 of 0.13 °C ± 0.03 °C per decade is almost twice as great as that of the last 100 years.
Cool climate area
In Europe, this includes Germany, England, the north of France(Beaujolais, Burgundy, Champagne and Loire), Switzerland and Austria, as well as overseas Canada, the New England states on the east coast of the USA, the southernmost part of Chile, parts of California (Anderson Valley, Carneros), the Cape in South Africa, the Australian island of Tasmania and the southern tip of the northern main island of New Zealand. The average temperature is below 16 °Celsius. Aromatic and fruity white wines from early-ripening grape varieties are typical of this temperature range.
Intermediate climate range
This includes Bordeaux and the northern Rhône Valley in France, Rioja in Spain, Tuscany and large areas in northern Italy, the Napa Valley in California and the south of Western Australia. The average temperature is between 16 and 18.5 °Celsius. It is mainly dark, alcohol-rich red wines that grow here.
Warm climate region
This includes southern France, the Portuguese Douro Valley, the island of Madeira, southern Italy, large parts of Spain and parts of southern Australia. The average temperatures there are between 18.5 and 21 °Celsius. These areas are particularly suitable for fortified sweet wines such as port, sherry, Malaga and Marsala.
Hot climate area
These include southern Greece, Turkey and southern Spain with an average temperature of 22 °Celsius. In addition to wine grapes, many table grapes and sultanas are also produced here. Areas or zones with almost the same climate, which can also be located on different hemispheres of the earth, are known as homoclimates.
Climate classification
This is used to classify the earth according to meteorological and climatological aspects on the basis of various criteria into so-called large climates (macroclimates) with a horizontal extent of at least 500 to several thousand kilometres. This is based on the different forms of vegetation, as the same plants only grow under the same climatic conditions. In order to delineate the zones more precisely, other criteria such as temperature and precipitation are often included in the analysis.
There are various classification systems, a very special system was used for all wine-growing areas in California (see there). Areas with the same climatic conditions are categorised into climate zones and thus classified. There are various models for this. One common classification is
Continental climate (continental climate, land climate)
This climate is characterised by large seasonal temperature fluctuations with a relatively large difference between the average temperature of the hottest and coldest month. It is characterised by hot summers with predominantly low cloud cover and humidity, as well as cold winters. The further inland a continent is, the less the equalising influence of the oceans, which is accompanied by a decreasing number of clouds and falling humidity. Compared to maritime areas (near the sea), there is relatively little rainfall with peaks in summer due to heat storms. Temperatures drop rapidly in autumn.
The differences between vintages can be considerable. High yields have a significant impact on quality. Continental climates are mainly found in inland Central and Eastern Europe, as well as in the interior of North America (in Canada and many states of the USA). It is best suited to fruity, dry wines with a corresponding acidity (especially important for white wines).
Marginal climate
This refers to a climate in the climatic border area in which viticulture is just possible (marginal = something on the edge/on the border). It is characterised by relatively low average temperatures and a long vegetation cycle. See also under northernmost vineyard and southernmost vineyard as well as under highest vineyard.
Maritime climate (marine climate, oceanic climate, sea climate)
A maritime climate (Latin maritimus = belonging to the sea) prevails in the vicinity of seas or large lakes, which act as an equalising temperature buffer. This is because the water temperature changes more slowly than the temperature on land due to its high heat capacity. As a result, the land near the coast is cooled by the sea in summer and warmed in winter (positive lake effect). For this reason, the five "Great Lakes" of Erie, Huron, Michigan, Superior and Ontario in the north-east of the USA and Canada also provide good conditions for viticulture. However, the mere geographical location (coastal location) alone is not an indication of a maritime climate, as the wind direction also has an influence.
The entire east coast of the USA has a continental climate because the wind blows from the west (the vast interior of the country) to the east. A maritime climate is characterised by moderately warm summers and mild, rainy winters. Temperatures are consistently warm with high humidity. Temperatures only drop slowly in autumn. Compared to continental climates, there are much smaller differences between day and night and summer and winter. The majority of Europe is influenced by a maritime climate. It also prevails in many areas of the southern hemisphere such as Australia, New Zealand and South Africa, even if these are inland.
Mediterranean climate (Mediterranean climate)
Typically characterised by hot, dry summers and mild, humid winters. Artificial irrigation is often necessary due to a lack of rainfall. Due to low humidity, there is generally a lower risk of fungal diseases. The best locations are at higher altitudes. The Mediterranean climate is characteristic of many coastal regions that lie on the western sides of the continents. These include the entire Mediterranean basin, south-west and northern Australia, the west coast of the USA, Chile and the Cape Province in South Africa. The climate produces fully ripe, high-sugar but sometimes low-acid grapes, which are ideal for high-alcohol sweet wines.
Pannonian climate
Influenced by the Hungarian lowlands, particularly in northern Burgenland/Austria. Foothills can be felt right up to the borders of the Wachau, Kremstal and Kamptal wine-growing regions, which are characterised by the contrasting interplay of the Pannonian and western continental climates.
Dry climate
A dry climate characterises many wine-growing areas in Israel, Italy, Spain, South Australia, South Africa and Chile, as well as the Central Valley in California in the USA. Due to the low rainfall and the risk of drought, viticulture is not possible without regular artificial irrigation.
European wine-growing zones
Under EU wine legislation, Europe has been divided into three large wine-growing zones A, B and (with subzones) C, which have similar climatic conditions. Special wine regulations apply to these zones, for example with regard to enrichment (alcohol increase), acidification and sweetening. Within these large climate zones, a distinction is made between smaller climate zones, although there are no 100% universally valid definitions. The hierarchy is based on the size of the vineyard area and is generally as follows (top-down):
Macroclimate
Larger area (also large climate) with a horizontal extension of at least 500 kilometres. It refers to the climate of a wine-growing area or region. As a rule, this is understood to be the term "climate". However, it is difficult to speak of a uniform climate within these large areas, as altitude, slope, compass direction and soil type have a major influence with varying effects. This manifests itself, for example, in different vegetation cycles in the vineyards.
Mesoclimate
Intermediate area between macro- and topoclimate ranging from ten to several hundred metres. It is increasingly replacing the terms topoclimate or microclimate.
Topoclimate
Term for a localised climate determined by the topography. This can, for example, relate to a single hill, a slope or a valley.
Microclimate (site climate)
This is a commonly used term for small-scale conditions that give a vineyard a very typical and individual flavour, which in extreme cases can even be different in a vineyard such as a row of vines. Components such as proximity to a pond, river or forest, soil heat storage, solar radiation, mountains (which can protect against wind), but also the vine training of the vines can play a role. This term is related to the French terroir.
Microclimate
Specific climate on the smallest scale of a few metres within a vineyard, for example on a vine, even on leaves and grapes.
Major climate changes
In the course of the earth's history, there have always been periods of serious climate changes that took place over immensely long periods of time. During the last 1,200 years, there have been three climatically different epochs that occurred relatively quickly. The first two events affected the northern hemisphere, while the third event affected the entire globe:
Medieval Warm Period
Between 900 and 1350, Europe in particular experienced a pronounced temperature peak, which is known as the Medieval Warm Period. The climate was so warm at that time that winegrowing was even successfully practised in southern England. From 1450, the climate began to deteriorate again with very cold temperatures.
Little Ice Age
The Little Ice Age was a relatively long-lasting climatic phenomenon lasting 400 years in the period from 1450 to 1850, which occurred worldwide with regional and temporal focal points in Europe,North America, Russia and China. There were particularly cold periods from 1570 to 1630 and from 1675 to 1715, which were associated with a worldwide expansion of glaciers. In a relatively short period of a few decades, this has developed dramatically in the opposite direction with the disappearance of glaciers.
Climate change
The current change is so frightening because it has developed in a very short space of time. Since industrialisation, the average temperature has risen by +0.7 to +0.8 °Celsius, with +0.6 °Celsius occurring in the last 30 years alone. Global warming and the associated climate change and greenhouse effect also have a major impact on agriculture and viticulture. The term decarbonisation has emerged in this context. Decarbonisation refers to the conversion of an economy, especially the energy industry, towards a lower turnover of carbon or a reduction in greenhouse emissions.
Extreme effects due to global warming with heat waves, drought and aridity as well as melting ice on the polar ice caps and rising sea levels with flooding of shallow coastal areas.
Institutions
The Climate Change and Wine Congress, set up in 2006, is dedicated to this problem area. There are other institutions that examine climate protection measures according to appropriate criteria. These include DINE and Fair'n Green (Germany), EMAS (EU), IWCA (international), myclimate (international), Nachhaltig Austria (Austria) and SQNPI (Italy) for the certification of quality labels for winegrowing businesses.
Further information
See also Biodiversity (promotion of biodiversity), Cool Climate Winegrowing (cultivation of vines in cooler areas), Decarbonisation (reduction of carbon dioxide emissions), Globalisation (effects on viticulture), IWCA (International Wineries for Climate Action), Climate change (through emissions), Sustainability (use of regenerative systems), Greenhouse effect (global warming through greenhouse gases) and Pollution (environment).
Map of climate zones: By LordToran - Self-created, CC BY-SA 3.0, Link
edited by Norbert Tischelmayer February 2019
Vine belt: Der Winzer 1 - Viticulture, Ulmer Verlag 2019, 4th edition
Climate change: Pixabay
Main source: WIKIPEDIA Climate and follow-up links
