Australia has always been a hot, dry continent. But as climate change drives temperatures higher and drought periods longer, the amount of water being lost to evaporation is increasing at a pace that is putting real pressure on farmers, property owners, and water managers across the country. Understanding the link between climate change and evaporation in Australia is the first step toward protecting your water supply for the future.

What Is the Connection Between Climate Change and Evaporation?

Evaporation is driven by energy — primarily heat. The more heat available at a water surface, the faster liquid water converts to vapour and escapes into the atmosphere. Climate change, by raising average air and surface temperatures, directly increases that energy supply.

According to the Bureau of Meteorology, Australia’s mean temperature has risen by approximately 1.47°C since 1910. While that may sound modest, even a one-degree rise in temperature translates to a measurable increase in evaporative demand — the atmosphere’s capacity to pull moisture from the land and water surfaces below.

Several climate-driven factors combine to make evaporation worse:

Higher average temperatures — directly accelerate the rate of water conversion to vapour
Longer, more intense heatwaves — sustained heat drives rapid and extreme water loss
Reduced cloud cover — in some regions, more sunshine hours increase solar radiation on open water
Lower humidity in inland areas — dry air has a greater capacity to absorb water vapour
Stronger and more frequent hot winds — wind strips moisture from the water surface faster

How Much Is Evaporation Increasing in Australia?

Pan evaporation records — the most widely used measure of evaporative demand — tell a clear story. In much of inland Australia, annual potential evaporation already exceeds 2,000 millimetres per year, far outstripping average annual rainfall in many regions. Climate projections from the CSIRO indicate this trend is set to continue, with southern and inland areas expected to experience declining rainfall and rising evaporation simultaneously — a dangerous combination for water storage security.

For property owners in Queensland, New South Wales, Victoria, and Western Australia, this means a double blow: less rain filling dams and more heat emptying them.

The Real-World Impact on Australian Farm Dams

For the average rural property owner, the consequences are practical and immediate. A 1-megalitre farm dam that once reliably held water through summer is now often running critically low by February or March. Stock water security, irrigation capacity, and emergency fire reserves are all at risk.

Consider a typical scenario: a 5-megalitre dam in inland New South Wales. Under normal conditions, that dam might lose 700,000 to 900,000 litres to evaporation over summer. Under conditions driven by a climate-intensified heatwave, that figure can approach 1.5 million litres or more — a loss equivalent to watering a large herd of cattle for months.

The same challenge plays out at a larger scale for councils managing town water supplies, irrigators managing network storage, and mining companies relying on process water reservoirs.

Which Parts of Australia Are Most at Risk?

While all of Australia faces increasing evaporation pressure, some regions are disproportionately affected:

The Murray-Darling Basin — already subject to intense political and environmental pressure over water allocation, rising evaporation is compounding the challenge of maintaining viable water storage across this critical agricultural zone
Inland Queensland and NSW — these areas regularly record some of the country’s highest evaporation rates, exceeding 2,500 mm/year in places like Broken Hill and Longreach
The Western Australian wheatbelt — declining autumn rainfall combined with hot summers creates severe water storage stress for farming properties
Northern Australia — while rainfall totals are higher, extreme heat and intense dry-season evaporation make wet season water capture difficult to hold

What Can Property Owners Do Right Now?

The good news is that while you cannot control the climate, you can control how much water your dam loses to it. There are proven and practical strategies that significantly reduce evaporation losses even in extreme conditions.

1. Install a Floating Dam Cover

Floating covers are the most effective single intervention for reducing dam evaporation. High-quality geomembrane covers can reduce evaporation losses by up to 90%, turning an open, vulnerable dam into a protected water reserve. They are particularly cost-effective for dams where water has high financial value — irrigation, livestock, or mining operations.

2. Optimise Dam Design for a Changing Climate

Deep, narrow dams lose proportionally less water to evaporation than shallow, wide ones. If you are building a new dam or extending an existing one, designing for maximum depth relative to surface area is one of the most effective long-term strategies. This is exactly the kind of advice the team at EvapCo provides, backed by over 30 years of dam construction experience through our sister company Big Ditch.

3. Use Evaporation Suppression Products

Biodegradable evaporation suppressants — typically food-grade fatty alcohol-based compounds — can be applied to open water surfaces to form a thin monomolecular layer that reduces surface evaporation. They are particularly suited to dams where a full cover is not practical.

4. Strategic Windbreaks

Planting trees or installing wind barriers on the prevailing wind side of your dam reduces the wind-driven component of evaporation. This is a low-cost, long-term investment that also delivers shade benefits and habitat value.

Climate Change and Evaporation: A Long-Term Challenge

Australia’s water future will be defined by how well property owners, farmers, and water managers adapt to the reality of a hotter, drier continent. Evaporation is not a new problem — but it is a growing one, and the gap between rainfall and evaporation in many regions will only widen in coming decades.

Proactive investment in evaporation control today is not just an operational decision. It is a resilience strategy — one that protects productivity, property values, and long-term viability in an era of increasing climate uncertainty.

Summary

Climate change is amplifying evaporation rates across Australia by raising temperatures, reducing humidity, and intensifying drought periods. Farm dams, reservoirs, and water storage systems are losing more water than ever before. Effective evaporation control — through covers, smart dam design, and suppression products — is the most practical response available to Australian property owners today.

Protect Your Water Supply Before the Next Heatwave

EvapCo specialises in evaporation management solutions for Australian conditions. Whether you manage a small farm dam or a large commercial water storage facility, we can help you reduce your losses and secure your water supply.

Talk to the EvapCo team today — backed by 30 years of dam construction and water management expertise.

Frequently Asked Questions

How does climate change affect evaporation rates in Australia?

Climate change increases evaporation rates by raising air temperatures, reducing cloud cover, and intensifying drought periods. In Australia, average temperatures have risen by 1.47°C since 1910, directly increasing the rate at which water evaporates from dams, rivers, and reservoirs.

How much water can a dam lose to evaporation in a hot Australian summer?

In hot inland regions of Australia, a dam can lose between 1,500 and 2,500 millimetres of water per year to evaporation. During peak summer conditions, daily losses can exceed 10 to 15 millimetres from the surface — equivalent to thousands of litres per day on a mid-sized property dam.

What can farmers do to protect their dams from increased evaporation due to climate change?

Farmers can reduce dam evaporation by installing floating dam covers, using shade cloth or geofabric, applying evaporation suppressant products, planting strategic windbreaks, and redesigning dam profiles to reduce surface area relative to storage volume. EvapCo specialises in tailored solutions for Australian conditions.