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You are here: Home > Water for farmers
Overview
Benefits and disadvantages
What to expect
Water shortages and changes in rainfall
Impacts on agriculture and livestock
Overview
Covering approximately 60 per cent of Australia, the agricultural sector uses more land and water than any other industry in Australia (ABS 2003). Due to the high water dependency, and adverse effects of climate change, such as increased temperature, likely decreases in rainfall, and increase occurrence of extreme weather events and drought condition, most farmers will experience negative consequences of climate change (Passey 2003). For this reason alone, farmers will play a major role in deciding how Australia will best adapt to climate change in secure sustainable water resources.
Benefits and disadvantages
Farmers will obtain some benefits from human induced climate change due to increased concentrations of CO2 in the atmosphere, which will stimulate growth and yield in many plant varieties (Passey 2003). However, the effects of climate change, such as higher temperatures, lower soil moisture, increased occurrence of drought, and likely reductions in annual rainfall in many parts of Australia, the negative impacts of climate change are likely to outweigh the positives (Passey 2003). Furthermore, experiments indicate that increased CO2 will stimulate chemical changes within plants that can lead to higher contents of toxins and less available proteins. Such changes could have adverse effects upon humans and grazing animals.
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| Image: Greenpeace |
What to expect
Already, many farmers around Australia are feeling the effects of widespread drought and water shortages. This has placed them in a particularly vulnerable position to future climate change scenarios of possible further decreases in rainfall and river flows, amongst other changes.
Water shortages and changes in rainfall
While average rainfall is expected to decline in many parts of Australia, both the intensity and frequency of severe rainfall is likely to increase in some parts of the country. For farmers, extreme rainfall events can disrupt growth and destroy crops. Overall, changes in temperature and water supplies under climate change will alter cropping patterns and regional suitability to crops (Howden et al 2001).
 Changes in rainfall & water systems
Changes in water availability under human-induced climate change are likely to bring about the following consequences:
IMPACTS ON IRRIGATION PRACTICES
As mentioned above, farmers are the biggest water uses out of all industry. This is largely due to their use of water intensive irrigation practices. Roughly 75% of water consumed for irrigation practices comes from the Murray-Darling Basin. Under climate change, the southern part of the Basin is expected to have significantly reduced water levels, which will directly impact upon a large portion of irrigation practices.
Changes in rainfall & water systems - Murray-Darling Basin
Another example of a likely impact on irrigation practices can be seen in the Macquarie catchment. By 2030, irrigation supplies in the Macquarie catchment are expected to represent less than 50% allocation of water rights for 5 consecutive years (Jones and Page 2002). In addition, there is a 1 in 3 chance that critical thresholds for irrigation allocations will be exceeded by 2030 if drought conditions under climate change continue to dominate.
To find out more about irrigation practices in Australia, visit the irrigation information page on the Australian Natural Resources Atlas website
EXTREME WEATHER EVENTS
Increased occurrence of extreme weather events such as floods, tropical cyclones, droughts, fire weather and dust storms will significantly impact upon agricultural production, with damage to infrastructure and increased insurance costs (Passey 2003).
OVERALL CURRENT SYSTEM FAILURE
If agricultural systems fail to adapt to likely changes in water supply under climate change, they may have unrealistic water requirements, which could lead to an overall current system failure if water efficiency changes are not instilled.
LOWER SOIL MOISTURE
With increased temperature and evaporation and potential decreases in annual rainfall, soil moisture is expected to be reduced in many southern parts of Australia (Pittock 2003). For example, catchments west of the Great Dividing Range are expected to experience a 10% decrease in soil moisture by 2030 (Jones and Pittock 2002). Decreased soil moisture will lead to an increased risk of crop failure and demand for water. Furthermore, the combination of increased occurrence of drought and lower soil moisture will make farmers more vulnerable to soil erosion, salinity and nutrient loss.
HIGHER EVAPORATION & INCREASED OCCURRENCES OF DROUGHT
The higher temperatures expected with climate change will lead to greater evaporation and exacerbate drought conditions (Karoly et al 2003). Higher evaporation rates make it difficult to sow crops and place existing crops under stress. Furthermore, increased evaporation will increase the water demand of farmers, amplifying competition between different water users.
REDUCED FROSTS
In many southern parts of Australia, frosts could be reduced by up to 20-80% (CSIRO 2004). Fewer frost will lead to misshaped fruit and lower yields, particularly with temperate fruits such as apples and stone fruit.
ECONOMIC IMPACTS
From the impacts listed above concerning climate change and water, the agricultural sector can expect to experience significant economic impacts.
Examples of possible economic impacts include:
- A reduction in economic returns in the Murray-Darling Basin of between $0.8 billion and $1.2 billion, depending on the level of greenhouse gases emitted (Beare and Heaney 2002).
- In the Macquarie Valley, a loss in Gross Revenue of $38 to $152 million dollars per year, or 6 to 22% under low or high greenhouse gas scenarios respectively. Here, livestock industries are expected to be worst off due to the scale of their operations (Hassel and Associates 1998).
Implications for Australia's major crops and livestock
Impacts on agriculture and livestock
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