Vintage Advancement and Compression in Australia Due to Climate Change
Paul Petrie* and Victor Sadras
*Australian Wine Research Institute and the South Australian
Research and Development Institute, PO Box 197, Glen Osmond, SA
5064, Australia (paul.petrie@awri.com.au)
A shift in phenological development is the most conspicuous
biological effect of recent warming, with advanced maturity
of grapevines reported in Europe, North America, and Australia.
Associated with the advancement in maturity are anecdotal reports
of compression of the harvest period, with different varieties
grown in the same region now reaching optimal maturity at similar
dates and
a narrower peak period over which a single variety matures. Given
the capital-intensive nature of the wine industry (processing
capacity is used at most for eight to 12 weeks per year),
climatic trends that compress harvests have the potential to
affect financial viability. This anecdotal evidence has been
difficult to validate and quantify. Analysis of commercial
maturity data from 1995 to 2015 suggested that vintage
compression was driven by two facets. First, there was consistent
reduction in the time interval between maturities of different
cultivars grown in the same region. For example, in the McLaren
Vale region, the range in dates between peak maturity of
Chardonnay and later-maturing Cabernet Sauvignon was ~20 days in
the mid 1990s and is now averaging closer to five days. Second,
individual cultivars are also reaching maturity over a shorter
period within one region. For example, Shiraz across the Barossa
region reached maturity over a 30-day period in the mid 1990s and
was reduced to a 15-day window by the mid 2010s. While this
analysis does not allow separation of the effects of warming and
management practices, there have not been step-changes in
vineyard management during the study period. Regardless of the
causes, the advancement in maturity and reduction in the duration
of the window of peak maturity illustrate the challenges faced by
wineries to process fruit over a shorter, more-intense period.
Funding Support: Wine Australia and the Australian Department of Agriculture and Water Resources, through the Filling the Research Gap program.
