Wladimir Köppen – a climate-vegetation genius, and what this has to do with wine

The Köppen-Geiger system is the most widely used climate classification. Thanks to a group at the Veternary Medical University in Vienna (Institute for Veterinary Public Health), everyone can check out the beauty of the system. Scientists and non-scientists. E.g. for picking the next holiday or long-burning questions such as: Why can't I find a Brazilian wine?

As an inhabitant of the temperate zone of the Northern Hemisphere (Europe is currently enjoying another cold February after a much too warm December and January; white Easter is still an option), you may be puzzled seeing the courageous Florida kids fighting the Windmills of the 2nd Amendment running around in tops.

The Köppen-Geiger climate map of the world provided by the Climate Change & Infectious Diseases Department, shows you why. Parkland lies in the tropical zone, it has an "equatorial" (= tropical) Am-climate with no winter.

A close-up on southern Florida, using the highest resolution Köppen-climate layer for GoogleEarth [EN/GE] provided by the Vienna group (Kottek et al. 2006; Rubel et al. 2016)

The second letter, here the "m", in the Köppen-Geiger classification refers to the seasonality of precipitation, "Am" means we have a monsoon-influenced climate with a lot of rain coming down during rain-season(s) [see also Weatherspark's profile of Parkland, FL]

A climate very different from the "warm temperate, fully humid, with warm summers" Cfb-climate covering a good deal of Europe.

Close-up of Europe. "Warm temperate" climates (C) in green colours; the "boreal" or "snow" climates (D) in purple; blue the tundra climates (ET) with no summer.

The purple-blue arcs in the green sea are the (high) mountains with D- and E-climates, the "snow" ("boreal") and "ice" (polar) climates. Everyone who does skiing outside the deepest of winter has passed the warm temperate (Cfb) — boreal (Dfb) climate boundary. Köppen defined this boundary, between climates without permanent snow cover and the Schneeklimate (snow/boreal climates, D) with permanent snow covers during winter, by quite an odd value. The mean temperature of the coldest month is > -3 °C (warm temperate) or < -3° C (snow/boreal).

But when you are aware of this boundary, you notice its brilliance. For instance, when I worked in Stockholm (Cfb), I flew in via Arlanda (near Uppsala, Dfb), Stockholm's main international airport. And quite often in winter, I would land in landscape powdered by snowflakes coming from a usually snow-free area (the Loire valley), even when the temperatures were quite the same (hence, I could bring my beloved beurre aux cristaux de sel without alerting airport security). But half-way between Arlanda and Stockholm, the white cover would vanish. Because you crossed Köppen's "generic" (which is a scientific term for gut-feeling) boundary between the snow (here: Dfb) and the warm temperate climate (Cfb).

For those living in more montaineous areas in the Cfb climate of central/western Europe, you can trace this phenomenon, too. In winter, you have to pass a certain height to find a much higher probability of persistent snow. This is where you leave the Cfb behind you and get into the Dfb. In Germany, only a few tops in the Mittelgebirge (our lower mountains) reach into the Dfb climate (too fine for the Vienna world map), and this is where you find (small) skiing areas (e.g. at the Erbeskopf, the mightiest of all mountains in the Hunsrück).

Equally odd values define other boundaries.

The equatorial (tropical) climates (A) are defined by no month with an average temperature below 18 °C. The polar (ice) climates by the fact than no month is (monthly average) warmer than 10 °C.

And we have climates with heiße (hot, Cxa, Dxa) – warmest month ≥ 22 °C, warme (warm, Cxb, Dxb) – at least four months with ≥ 10 °C, and kalte (cool, Cxc, Dxc, Dxd) summers (wether "c" or "d" depends on whether the winter months can be colder than −35 °C).

The Gasadalur panorama. Typical Cfc — warm temperate, fully humid climate with cold summers (picture taken in summer, we had comfy max. 15 °C). Cold summers are too short and cold for most trees, the Faroes have essentially none, because the short summers come with a lot of wind and only few places have proper soil. This and more pictures on the Faroe Islands by Christian Pott can be found at solsidan.de.

The second letter (x) represents the seasonality of precipition, which is important to keep in mind when choosing a good holiday destination. "f" stands for (immer)feucht, fully humid, meaning that throughout the year, there is enough rain. "w" stands for wintertrocken, much less rain in winter than in summer; extreme versions related to the monsoon effect (lots of rain in summer/rain season) are indicated by the above-mentioned "m". "s" stands for sommertrocken, typically little to no rain during summer.

And when precipitation is generally scarce, we enter the Trockenklimate, the dry (B) climates. Which include heiße and kalte Steppenklimate (hot and cold steppe climates; BSh, BSk) and the desert climates, with very little rain – in German Wüsten, hence BWh (e.g. Sahara [Wikipedia/LiveScience]) and BWk (e.g. the Gobi desert)

Obviously not the Faroes. NMU's park with some imported animals. Port Elizabeth's BShHeißsteppe, hot steppe – climate.

Just a little trip towards the west and inland. Rarely burned (but spikey and viny) forest in the Island Nature Reserve, happens to be in a Cfa cell.

Only 25 km in-between bush (NMU's park) and forest (Island Nature Reserve), but two climate grid cells. Warm temperate, fully humid (Cfa) = forest; dry and hot steppe climate (BSh) = (burned) bushland. Quite a co-incidence.

What has the Köppen-Geiger climate system to do with wine?

Csa climates, summer dry, warm temperate climates with hot summers are everyones darling. Ideal for beach holidays and growing wine.

Even in France, one can buy wine from outside France (but you don't want to get caught doing it). From California (Csa), but not Georgia (U.S. state) and the Carolinas (Cfa), from Chile (rarer Argentina; Csa) but not Uruguay or southern Brazil (Cfa). The quite famous South African wine region, Stellenbosch, is – naturally – Csa, but try to find a wine form the Eastern Cape or Natal (Cfa mostly, if not a dry steppe climate).

And the reason why you find occasionally (in France) Australian wines but hardly those from New Zealand, can be explained by the Köppen-Geiger classification of down-under.

Close-up of Australia and New Zealand. Wine is grown all across Australia (maybe because it was mostly colonised by British convicts, and not French viticulturistes), but viticulture is concentrated in the mild climates with dry and/or hot summers (Csa, Csb, Cfa climate of south-eastern Australia). Many of these wines are also exported to Europe (see also Wikipedia article(s) on Australian wine showing a map of the Australian "wine zones")

Wine does like some dry feet during summer. But what about the French wines (Bordeaux, the Loire and Rhone valleys are mostly Cfa or Cfb approaching Cfa), like many Australian wines (e.g. from New South Wales). The f means fully humid, enough rain during all of the year. And there are now English wines (Channel coast, not really an export runner yet), and quite a lot in Germany (mostly Cfb, similar to New Zealand). One famous wine of Georgia (the Caucasian country) is the Mukuzani, grown in a Cfa climate.
The a tells informs us about the hot summers in these regions; the hotter the summer, the higher the evaporation. Furthermore, all of these wines grow in well- or extremely drained soils, the water does not get stuck in the ground. (PS you can grow wine at the boundary between hot and cold steppe climates, BSh-BSk; but you have to irrigate to compensate for the lack of sufficient spring precipitation; otherwise, you don't grow grapes, but raisins).

For example, the Riesling of my home area (Cfb) can be so dry that clouds above you seem to vanish, when you open a bottle. Or so edelsüß, that crazy people pay > 1000 $ for a bottle of white wine that you have to drink (you can't cellar it, like high-end red wines). Riesling is usually grown on schist, most rain just goes directly into the gullies. And the black of the shist plates heats the wineyard from below. On sunny days, you can watch the raindrops evaporating soon after touching the schist plates. And guess the facing direction of our most productive Wingerten (vineyards): Südhänge, more or less south-facing slopes in the river valleys.

Viniculture in the Mosel valley (Cfb), introduced by the Romans (our "capital" city, Trier, has an over 2000-year history). Photo taken in mid-winter 2002, note the lack of snow,

To put it in a simple equation, regarding growing wine, the easiest is Csa followed by Cfa (dry-ish soils) and mild Cfb/Csb (mostly white wine grape sorts, though). BS is tricky (see above). By the way, the reason why Chinese, one of the five food high cultures, rather buy empty European bottles to re-fill them with their wine than to market their own wines, can be explained by Köppen-Geiger, too. They have no Cs-climates, and the Cf-climates are more similar to Cw-climates because of the East Asian Monsoon: too much rain in summer.

Close-up on China (proper). The lush-green Cfa is the area, where you can find a multitude of crops. Together with the southern, subtropical Cwa it forms a refuge, for quite a bunch of odd plants that should have gone extinct long ago (and did so in other parts of the world) such as the famed ginkgo, the lesser known dawn redwood (you can find both as fossils on the Faroe Islands), and Rhoiptelea, a relative of the walnuts you probably have never heard of, but its flowers and pollen can be found in the middle Cretaceous (c. 90–85 million years ago) of Europe. See also this Wikipedia animated map of the Chinese empires and main states

But it's perfect for tea.

View across the roofs of the Baoshan Buddhistic temple into the tea plantations, we visited in 2012; on the island in the middle of the Taihu Lake, where a princess' tears became white tea – more Cfa photos (in much better resolution) from the Taihu area by my former colleague Christian Pott can be found on solsidan.de.
Turkish Cfa, where the tea leaves for çaykur come from.

Just to show-off Wladimir Köppen's brilliance, guess what you can find in den Cfa climate pocket in north-eastern Turkey? They are growing çay, of course, too (in case you wonder why it is cha/çay or te/tea, see e.g. this post; and World Atlas of Language Structures. It reached Turkey by land, and England by sea).

What Köppen-Geiger maps can tell about the future (of wine and summer-retreats)

Certain political circles ignore it, but we have (human-enforced) global warming. And the Vienna group provides a simulation for this century, indicating e.g. where the fully humid hot summer climates will be likely replaced by summer dry versions, and from time-to-time quite chilly Cfb by hot summer Cfa.

Köppen-Geiger maps of the future, using the conservative scenario tested by the Vienna group (you can find movies for the tested scenarios on the Vienna homepage)

Just in case you wondered, why the wine from your favourite region gets stronger and stronger (I'm a great fan of reds from vigneries around the Mont Ventoux, now typically with 14 or 14.5 Vol.%). And where to invest for your grand-childrens exotic wineries ... the Bretagne and Cornwall is worth a try, Sussex seems a sure go, and remember: to build up a wineyard from scratch you usually need a generation. The Vienna simulation for the Köppen-Geiger classification of the future world can help you to be prepared. Not only regarding wine, but where to retire and buy a summer house that is of use to future generations. You can also fathom why the Russians have no great interest to slow-down global warming, in contrast to e.g. (U.S.) Americans. For the Chinese, it's tricky (some winners, some losers).

Postscriptum. Many other plants show similar attachment to Wladimir Köppen's climate zones. Because Köppen was not only a climatologist, but also a (geo)botanist, and the primary basis for his classification was his knowledge about vegetation. His original concepts included a Buchenklimat (a beech tree climate) and Eichenklimat (oak climate), climate zone defined by whether you still find beech trees (Dfb), or only (white) oaks (Dfc). Knowing in which climate an ornamental plant occurs can help you to decide if it would be a good idea to plant it in your garden. And for scientists, there is an awful lot to dig out, but this is a topic for another post (or posts).


World maps of Köppen-Geiger classification: http://koeppen-geiger.vu-wien.ac.at/  includes layer gmz-files for GoogleEarth (several resolutions, you need a strong computer for the highest used for screen shots shown in this post), the basic data (different formats), and a wealth of information (for scientists and non-scientists): modern-day climate, climate shift using different scenarios, special maps for the U.S. and the Alps, and downloadable papers/maps by Wladimir Köppen [for most of his classic works, you need to be able to understand German]. If you make use of this (or re-use my adapted pictures), make sure to give them the due credit.

NASA Earth Data provides an alternative 0.1° (latitude-longiture, not Celsius) Köppen-Geiger world map by Peel et al. (2007), which corrected some errors of Kottek et al.'s (2006) map.

An introduction to the Köppen-Geiger classification, further links, and a comparison with the U.S. American modification by Trewartha (who separated the subtropics from the warm temperate zone) can be found in this post.

For those interested in wine-related data, I recommend a visit to the The Wine Gourd blog by David Morrison, my fellow co-blogger and initiator of the Genealogical World of Networks.

Cited literature
Kottek M, Grieser J, Beck C, Rudolf B, Rubel F. 2006. World map of the Köppen-Geiger climate classification updated. Meteorologische Zeitschrift 15:259-263 — the principal citation for the used world maps. [PDF]
Peel MC, Finlayson BL, McMahon TA. 2007. Updated world map of the Köppen-Geiger climate classification. Hydrology and Earth System Sciences 11:1633–1644. [PDF]
Rubel F, Brugger K, Haslinger K, Auer I. 2016. The climate of the European Alps: Shift of very high resolution Köppen-Geiger climate zones 1800–2100. Meteorologische Zeitschrift DOI:10.1127/metz/2016/0816 — open access, the citation for the highest resolution (downscaled) maps.

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