Regionally specific climate change impacts

The latest information from the Victorian government about the future climate in the mallee predicts that it will be hotter and drier.

• www.greenhouse.vic.gov.au

Quick Links

• Temperature
• Rainfall
• Drought
• Humidity
• Climate change impacts on water availability
• Climate change impacts on regional crops - general
• Climate change impacts on regional crops - crop specific

Temperature

Daytime maximum temperatures and night time minimum temperatures will warm at a similar rate and warming will be similar throughout the seasons.

The number of days over 35°C is expected to increase by 5-30% by 2030 and by 10-200% by 2070. This equates to a potential worse case scenario of over 60 days per year over 35°.

The number of frost days is expected to decrease by 30-70% by 2030 and by70-100% in 2070. This equates to a potential worse case scenario of no frosts occurring in the mallee.

Rainfall

Rainfall in winter and spring is likely to decrease, however these decreases will likely be strongest in the spring. Generally changes predicted are -15 to +3% by 2030 and -40 to +10% by 2070.

Table 3; Predicted rainfall changes

Drought

Droughts are likely to become more frequent, more intense and longer, particularly in spring and summer.

Dry conditions that currently occur on average one in every five years may increase to up to one in three years by 2030.

Evaporation rates will increase as will the risk of bushfires. Soils will likely become drier, even if precipitation increases.

Humidity

Humidity is expected to decrease over most of Australia. In summer and autumn, decreases of up to 3% by 2030 and 9% by 2070 are projected, with larger and more widespread decreases occurring in winter and spring.

By 2090, the cloud cover is expected to decrease by 2 to 4% in summer and 4 to 6% in winter.

Climate change impacts on water availability

Climate change impacts on water supply may be the biggest impact that we can't control.

• http://www.rirdc.gov.au/reports/RPLS/07-121sum.html

The CSIRO Murray Darling Basin Sustainable Yields Project will estimate water availability across the Murray Darling Basin (MDB) on an individual catchment and aquifer basis. Results will be used by the MDB Authority to develop the new sustainable diversion limit for the MDB.

• http://www.csiro.au/partnerships/MDBSY.html

Adjustments to the new sustainable diversion limit for the MDB will be achieved through increasing productivity, trade, monitoring and management and buying entitlements from 'willing sellers'. According to the website, the Federal government will 'not compulsorily acquire water entitlements'. The Sunraysia, Riverland and NSW are included in the 'Murray' region in the project and have not yet been completed.

At the 2007 Greenhouse Conference, Bryson Bates, Leader, Water in a Changing Climate Project, CSIRO highlighted the following implications of Climate Change on our water supplies;

• The Murray Darling systems will receive 10-25% less runoff by 2050
• Demand for water is increasing from urban and rural sectors, for energy generation and for the environment
• Little is known about Climate Change impacts on groundwater recharge, water quality (from fire, flash floods, drought) and aquatic ecosystems.
• There have been no integrated assessments involving water quantity and quality, water demand, salt interception schemes, revegetation policies, water pricing & trading policies.

• http://www.greenhouse2007.com/keynotes.htm

Climate change impacts on regional crops - general

In December 2007, The Australian Bureau of Agriculture and Resource Economics (ABARE) commodities report stated that "Australia is projected to be one of the most adversely affected regions from declines in agricultural production driven by climate change."

• http://www.abareconomics.com/publications_html/ac/ac_07/ac_07.html

Although much of ABARE's work concentrates on other industries, it has examined the economic impacts of climate change relevant to horticulture and they include;

• Negative impacts on temperate fruits and nuts due to increases in hot days and nights;
• Grape quality reduced by hot spells
• Queensland fruit fly may become a bigger problem .
• Damage to crops from heavy rainfall, soil erosion, waterlogging.

ABARE has identified the following general adaptation options relevant to horticulture;

• Change varieties or species grown
• Change fertiliser and irrigation timing and amounts
• Water harvesting techniques, soil moisture conservation
• Improved pest and disease and weed management
• Seasonal forecasting to reduce production risk, futures, water trading etc to manage income risk
• Diversify income, off farm
• Offset increased costs of managing climate with reduced costs elsewhere
• Multiple holdings in different regions
• Reduce nitrous oxide emissions through better use of fertilisers, N inhibitors, split fertilisation

• http://www.abareconomics.com/interactive/ac_sept07/htm/a1.htm

Climate change impacts on regional crops - crop specific

Data on the impacts of climate change on specific horticultural commodities is limited. We are currently asking local industry representatives for their comments on the implications of climate change on the future of different crops in Sunraysia in the future. Further information will be presented at Workshop 1 on Monday 28 April.

Wine grapes

Dr Leanne Webb has completed a PHD on the potential impacts of climate change on Australian viticulture. "Temperatures in most Australian wine regions are projected to increase by between 0.3 to 1.7 degrees Celsius by 2030".

Dr Webb modelled the effect of this temperature increase and showed that bud burst and harvest are likely to occur earlier and seasons are likely to be shorter.

For example she concludes that by 2030, the following changes can be expected for Cabernet sauvignon and chardonnay in the Murray Valley (which includes Sunraysia and Swan Hill).

Table 4; Projected changes to Cabernet sauvignon and chardonnay phenology in 2030

The shorter growing season projections are similar to that experienced in 2007 in many regions, when many in the industry struggled to manage the logistics of a short harvest (e.g. winery capacity, harvester availability etc) and the shorter window 'within which to determine the optimum harvest time for individual cultivars" (Webb, Whetton and Barlow, 2007).

The earlier harvest dates projected mean that the temperatures at harvest in 2030 are likely to be 1.6°C higher for Cabernet sauvignon and 1.8°C higher for chardonnay.

Climate change is also predicted to reduce wine grape quality in the Victorian Murray Valley (which includes Sunraysia); specifically declines are predicted to be up to 33% by 2030 .

Adaptive potential
'In the face of this potential threat of climate change to the Australian wine industry an exploration of the adaptive capacity of the industry has been undertaken. The potential for new sites or perhaps better-suited varieties to the projected warmer climates was investigated. It was found that suitability of varieties to different regions may change as the climate gets warmer. Some varieties will be able to be planted in regions where previously they would have struggled to ripen. Some regions will become too warm to produce balanced wines from some or maybe even all grape varieties. There is potential to adapt in many cases, either by planting different varieties or developing new winegrowing regions' (Webb, Whetton and Barlow, 2007). The writers go further ''attention is drawn to the need to investigate for the potential to introduce, or breed for, varieties suited to hotter climates.'

Almonds

In general ABARE predicts that "As it gets hotter crops requiring winter chilling, like almonds, may have yield reductions from warmer winter temperatures".

Local comment
The reduction expected in winter chill units may affect ideal sequencing of flowering patterns of different varieties. Extra attention will need to be paid to flowering times, pollination and bee strength preparation as trees respond to changing conditions. However, warmer and drier conditions in August/September during flowering will be a positive for tree and crop growth.

Future plantings should consider varieties grown in Southern California that currently experience the conditions anticipated for our region in 2030.

The modern fertigation and irrigation application methods that apply water as a plant uses it, pulse applications of nutrients as the tree needs, thus minimising losses through the soil profile, will allow tree health and growth to be maximised.

However soil conservation may need greater care with drier, windier conditions in Spring and Summer eroding and decimating the very dry and weed free conditions between tree rows. Planting of summer dormant medics which are highly drought tolerant would be essential to manage soils in these conditions.

Economically, crops with high protein and general health benefits like almonds will continue to demand high prices, allowing almond growers to compete for high-priced water.

Social impacts of climate change

The Climate Action Network Australia website provides a big picture summary of the potential social impacts of Climate Change for Australia. Below are excerpts from the site to summarise the impacts likely to be relevant for Sunraysia.

• http://www.cana.net.au/socialimpacts/index.html

Farming and rural communities
'Regional communities most at risk from Climate Change are those relying on agriculture, especially irrigated agriculture and tourism'

Insurance
'Costs will increase for everyone' however Sunraysia is unlikely to experience the extremely dangerous weather events (e.g. cyclones etc) predicted for northern Australia, or the huge bushfires expected in dried off mountainous areas with very high fuel loads, except along the river. Hail storms may increase more and they can be very damaging for horticulture crops so hail insurance costs may increase.

Tourism
Increased temperatures may affect tourism to Mildura. Conversely the huge carbon footprint associated with air travel may make local travel more attractive. Likewise the extreme impacts of climate change on coastal areas and large cities may make regional cities like Mildura very attractive as a place to live.

Employment
Will we get fruit pickers when it is that hot? New job opportunities will develop related to renewable energy production e.g. solar. There may be a move to decentralised energy production once the state is no longer tied to brown coal in Gippsland.

Health
Deaths due to heat stress, especially in poorer areas with no air conditioning. Sunraysia is unlikely to get the increases in infectious diseases expected in northern Australia, except increased incidents of Ross River fever.

The reduced liveability due to increased temperatures may impact on population growth, tourism and agriculture.