During a whirlwind agribusiness tour of South Australia, Food magazine was lucky enough to be able to meet some of Australia’s leading scientists in crop science and viticulture, whose research focuses on how the South Australian and Australian agricultural sectors can best prepare for a changing climate.
Food manufacturers and producers around the world are already seeing the effects of extreme weather events on their productivity and livelihood and some are arguing that climate change is threatening the global food supply.
To minimise the impacts of climate change, the South Australian Research and Development Institute (SARDI), is currently undertaking a number of climate change application projects aimed at reducing and managing risks within the viticulture sector, including:
- “Decompressing harvest and preserving wine identity”: a project led by Professor Victor Sadras which focuses on the effects of elevated temperature in grapevine physiology, berry traits, wine attributes, and viticultural practices to minimise the undesirable effects and maximise on the beneficial warming effects expected in the future.
- The Grape and Wine Research and Development Corporation (GWRDC) project series which includes the GWRDC Managing the impacts of climate change rainfall decline on vine balance and root activity, led by SARDI’s Principal Scientist Dr Michael McCarthy.
Nicknamed the ‘winter drought project’, McCarthy’s GWRDC project is located in South Australia’s famed winemaking region, the Barossa, and is designed to simulate climatic conditions that the Barossa is projected to experience in 2030-50. The vines are positioned under rainout shelters, preventing them from receiving natural rainfall in winter and spring, and are instead exposed to artificially replaced rainfall or drip irrigation at different levels based on the climate projections for rainfall.
“There are some people saying that the wine industry is the canary in the coalmine in terms of sensitivity,” says McCarthy. “The approach we are taking is that the climate has always been variable. There is nothing new about a variable climate. But, if we can get growers to understand how to better manage existing climate variability, then they will be in a better position to manage any future climate change.”
Should the projected changes in climate occur, McCarthy says that wine varieties which are currently well adapted to the present climatic conditions in particular regions, may not be as well adapted in years to come.
“What is beginning to happen in Australia and elsewhere is that certain varieties are now being identified in certain regions: the Clare Valley/Eden Valley for Rieslings, the Barossa Valley for Shiraz and so on. Those varieties are well adapted to those environments under current conditions.
"Now if we go forward 50 years, and accept that we are going to be warmer and drier, are those varieties still going to be as well adapted to those regions as they might be at the moment? Do we continue to grow those varieties in those regions, and accept that there will be a change in wine style, or do we start to look at wine varieties that might be more suitable for those regions under a warmer environment? That is the challenge.”
So how exactly will a change in climate affect grapes?
In their research, Professor Victor Sadras’ team has found that to get the same colour in red grapes under warmer conditions, the fruit must be left on the vine for longer. The problem this presents is that while the fruit matures to an acceptable colour, the sugar content – what becomes alcohol in the wine – also increases.
“To achieve the same colour level – the trade off might be a higher alcohol content,” says McCarthy. “The wine industry is trying to be responsible in terms of alcohol use, and we don’t really want to be promoting higher alcohol wines… So again that is management and varietal choice that we will have to explore into the future.
“What the consumer may need to accept is that, in 50 years time, Shiraz out of an individual region, anywhere in the world may taste different to how it does now.”
Another issue for industry relates to ‘compressed vintages.’ With increasing temperature, a greater proportion of fruit is ripening in a shorter time window, resulting in a compressed harvest period. This results in a significant strain on harvesting resources and logistics as the time available to transport and process the fruit is compressed.
“The problem with this is that there are more grapes ready to harvest on any one day than there has been before, so that has all of these downstream effects, such as the ability to harvest the fruit, the ability to transport the fruit and the ability to process the fruit in the winery in terms of crushing capacity, fermentation space and all those sorts of things,” explains McCarthy.
Sadras’ project is testing the feasibility of using delayed pruning as a means to “decompress” harvest, and also to preserve the local identity of iconic Australian wines. “The alternative of expanding the capacity to deal with more fruit in a shorter time is not feasible, as wineries already lock significant capital in equipment which is used for a short part of the year,” Sadras said.
In addition to the potential need for more capital investment, McCarthy says that a warmer climate may necessitate different management approaches, winemaking techniques and potentially new wine varieties as the sugar content continues to rise in the grapes.
“Will it be different management in the vineyard, new winemaking techniques that the winemakers will use? Or will it be that we actually have to start to look at other varieties within a region to stretch out that harvest?” says McCarthy.
He says that the overall goal of the project is to provide the necessary tools that wine growers need in order to manage existing climate variability, and this will in turn put them in a better position moving forward.
“We have always had drought, we have always had wet years, we have always had hot years, but because the value of the crop is now so high, growers cannot afford to lose a crop. The question is now about the management and what we need to do to manage these wet years, dry years and extreme heat events.”
The Decompressing harvest and preserving wine identity project is funded by the Grape and Wine Research and Development Corporation (GWRDC) and the Australian Government through the Department of Agriculture. It involves close partnership with industry (Dr Paul Petrie, Treasury Wine Estates) and colleagues at the University of Adelaide.