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Climate variability and change

Australia has always had a variable climate – it is a land of droughts and flooding rain. There is now overwhelming scientific agreement that climate change is occurring.

We know changes in global and regional climate patterns will have significant impacts on water availability for both communities and the environment across the Murray–Darling Basin. Many of its effects are uncertain and the timeframes are unclear.


Key facts

The Murray–Darling Basin is complex, diverse and constantly changing in response to the climate and human activities.

The Bureau of Meteorology predicts rainfall will decrease with climate change. Variability is also predicted, with declines less certain in the northern Basin.

Projections suggest an increase in drought frequency and severity. At the same time heavy rainfall is expected to increase.
CSIRO warns that outflows at the River Murray mouth in South Australia are likely to be influenced by climate change by 2030.

Less rainfall will affect the storage of water and increase demand from irrigators and communities.

Monitoring, new science and evaluation are at the core of adaptive management in the Murray–Darling Basin.


In 2012, there was widespread agreement across government that a plan was needed to manage our water carefully and protect the Basin for future generations. The Basin Plan sets sustainable diversion limits, which limit how much water can be used, to ensure there is enough water to sustain natural ecosystems.

The Basin Plan has been developed to ensure climate variability and climate change is considered in real-time and climate change patterns, measured over decades, are considered through regular reviews.

Monitoring, new science and evaluation are at the core of adaptive management in the Basin. The Murray–Darling Basin Authority (MDBA) will continue to work in close collaboration with the scientific community and key stakeholders to understand, explore and adapt water management mechanisms to factor in the latest climate change science and build Basin resilience in a drier, hotter future climate.

  • Climate variability describes the way elements such as temperature and rainfall differ from the average across months, seasons, years, decades and even centuries. Consecutive summers, for example, will not all be the same, with some cooler and some warmer than the long-term average.
  • Climate change refers to a statistically-significant trend in climate over many decades.

Water management practices in the Basin already account for climate variability. Water is allocated based on availability. In a wet year, more water will be available compared to a dry year.

To specifically address climate change, regular 10 yearly reviews of the Basin Plan are required, which allow for emerging climate change patterns to be considered. These reviews could result in changing water limits or other water management arrangements.

MDBA and the climate change work ahead

In February 2019, the MDBA released a climate change and the Murray–Darling Basin Plan discussion paper. The paper explains the impact of climate change across the Basin; explores how the current Basin Plan settings and various water management mechanisms are designed to adaptively manage climate change impacts; and looks ahead to the objectives and implementation of a climate change research program for the MDBA.

The discussion paper raises a number of focus questions to stimulate thinking around climate change risks and adaptation in the Basin. A series of climate change workshops during 2019, involving the MDBA’s independent Advisory Committee on Social, Economic and Environmental Sciences (ACSEES), government and independent experts, will explore what further research is needed to answer these questions, and how the MDBA can collaborate with the research community to get this work underway.

Expert knowledge

We work with other Australian Government agencies to understand climate risk and manage the Basin’s water resources under these changing conditions. These include:

  • The Australian Bureau of Meteorology
  • Basin state and territory governments.

Adaptive management

A cornerstone of the strategy for managing water resources in the Basin is adaptive management – ‘learning as you go’ by trialling techniques, monitoring, and making changes as needed.

Water managers must be flexible and dynamic to ensure the best possible outcomes are achieved. This is the modern way of managing natural resources.

Adaptive management allows governments and communities to adjust their approach in response to current climatic conditions, new information and local knowledge when planning for the future.

The features of this approach are planning, management, monitoring and evaluation. Adaptation can happen at any one of these stages.

The adaptive management approach to water for the environment is a practical example of adaptive management method at work. Alongside our partners, we have put in place monitoring programs to assess whether water for the environment is reaching the right places at the right times. Timings, flows and target areas are adjusted in response to the results.

Responding to climate change

We are focusing on 4 key actions to respond to risks and prepare for the impacts of climate change:

  • Refining existing arrangements - to support adaptation to climate change (such as water trade), avoid duplication and disrupting stakeholder operations.
  • Buffering the system from stress – preparing the Basin for climate-related stress (including recovering water for the environment) will mitigate the impact climate change has on its ecosystems.
  • Enhancing with new arrangements – there are opportunities to implement new initiatives that explicitly address climate change (such as greater collaboration with the research community) to generate a deeper understanding of climate change impacts on water.
  • Adapting to future changes – adaptive responses to climate change are being developed following monitoring and investigation into impacts. These are articulated in longer-term plans and, on a shorter time scale, in annual environmental watering priorities.