Monday, August 31, 2020

Australia's exciting new national wine climate atlas

We are constantly told that high-quality wine depends as much on the local climate (terroir) as it does on the skill of the winemaker (eg. If you want ‘authentic’ wine, you need to understand terroir). This is formalized in most wine regions by recognizing explicitly demarcated and named local areas. Only grapes grown within those areas can make wine marketed with the designated area name. [Note: it is the name that is legally protected, not the wine itself!]

This approach leads to an obvious requirement: an atlas of the grape-growing characteristics of the local environment for every square inch of the planet. That way, we would be able to work out:
  • what grape varieties are currently likely to do best in each area
  • what the environment might be like in the near future (given global climate change)
  • what grape varieties we could be trialing now, to meet that change.
This would be pretty nifty to have, bit neither you nor I is expecting to see it any time soon.

That is, unless you happen to be an Australian, because then you would already have this for your entire country / island / continent. The Australian wine industry is a pretty pro-active affair, not least because it has had to muscle its way into a business already pretty occupied by Europeans and North Americans, and with a bunch of South Americans chasing close behind. To make some space for yourself, you need to do something not just new but very different (eg. developing bag-in-box packaging, as well as the Stelvin screwcap).

To this end, there is a government authority called Wine Australia (originally founded in 1981, under another name), which regulates and promotes the national wine industry. In March this year it released the results of a 3-year project called Australia’s Wine Future: a Climate Atlas. This is a free online resource of climate information nationally, for all designated wine areas (which are formally called Geographic Indications). It provides detailed climate information since 1960 for each of Australia’s GIs, along with projections indicating how the climate is likely to change in the near, mid and long terms (as far as the year 2100).

Here is an example page from the Atlas, covering the Hunter region, north of Sydney — the first wine region I ever visited (40 years ago), and apparently now a hotbed of pandemic land sales (Hunter Valley vineyards fly out the door). There are five information pages for each GI, and this shows the example for Heat, in the Hunter (click to enlarge).

The Atlas graphs a bunch of climate indices, including:
  • temperature (one page) growing season temperature (GST); growing degree days (GDD);
  • rainfall and evaporative demand (two pages) annual, monthly and seasonal rainfall; growing season rainfall; number of rainy days during harvest; annual, monthly and seasonal aridity; number of dry spells before harvest;
  • heat extremes (one page) extreme heat factor (EHF) during a heatwave; heatwave duration and intensity; number of days per year exceeding specified temperature thresholds; frequency of days with high human heat stress;
  • cold extremes (one page) number of days at risk of frost during the growing season; daily minimum temperature; annual chilling degree days; number of days per year below specified temperature thresholds.
The GI maps are based on either a 5 km or 10 km grid, which is good enough for most agricultural purposes, but not fine enough for detailed vineyard planning — however, there is ongoing project using AI to map Australia’s 65 wine regions row-by-row (cf. the satellite imaging used by the Saturnalia system). The Atlas meteorological data often explicitly compare the 19611990 period with the 19972017 period, the latter being after the effects of global climate change started to become really obvious — this makes it clear just how much our world has changed within my lifetime.

The final report on the research project can be found here (PDF) with all of the methodological details. The various parts of the Atlas itself (PDFs), are linked at the bottom of the page here (arranged by GIs within states).


Australians have always referred to their homeland as The Lucky Country. The rest of the world wine industries should be so lucky (or, better yet, well organized).

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