Australia needs large-scale action to beat growing salinity problems
Australia is facing massive economic, environmental and social challenges due to the widespread and growing phenomenon of dryland salinity, a National Science Briefing was told in Parliament House, Canberra this week.
Alex Campbell, Chairman of Australia’s National Dryland Salinity Program, told the Briefing that more than 80 regional towns and cities have costs related to salinity – and even Sydney is being affected. The costs include damage to building foundations, bridges, pipelines and roads.
“Up to 30% of regional roads are being affected with major highway reconstruction costing up to AUS$1 million per kilometre,” he says.
Campbell stresses that unprecedented changes in management practices are needed. “We also need to explore the broader options of saline aquaculture and growing various salt tolerant pastures, crops and woody perennials,” he says. “With effective research and management, we could use salinised resources beneficially for both economic and environmental outcomes.”
“The costs associated with meeting these challenges are high, the costs of doing nothing incalculable,” says Dr Tom Hatton, CSIRO Land and Water. “Australia currently has 2.5 million hectares of salt affected land and this is likely to increase six fold in the coming decades,” says Dr Hatton.
“Western Australia, one of the worst affected states, has 1.8 million hectares of salt affected land and this is increasing at a rate equal to one football field an hour,” he says.
“Lost agricultural production exceeds $130 million annually, costs to infrastructure are over $100 million per year, lost water resources are valued at around $100 million each in some local supply catchments and the impacts on biodiversity are huge and include wetlands of international significance – all attributable to salinity,” he says.
Clean drinking water is also at stake. In South Australia at least 20% of surface water resources are sufficiently saline to be above desirable limits for human consumption. Next century these limits will be pushed further and for longer periods.
“To achieve significant improvement of the salinity problem, we need intervention on a massive scale,” Dr Hatton claims. “Research has shown that marginal intervention returns less than marginal salinity abatement. The large-scale salinisation processes we have set in train are insensitive to all but the most aggressive remediation.”
For example, he says tree planting is needed across most of the landscape, including 50-70% of catchment areas, to achieve significant reductions in the ultimate extent of the salinity. Dr Hatton emphasises, however, that the response times of salinity control will be long and it is unlikely these systems will be completely restored within normal human timescales.
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