Climate data and modelling in Regional water strategies

New climate data and modelling

Regional water strategies will be underpinned by new climate data and modelling that improves our understanding of past climate conditions and plausible climate futures, providing a more accurate picture of extreme climate events.

We are using a new four-step approach to better understand past and future climate risk.

1. Historical data – in the first step, we analyse past 130 years of recorded climate data and the climate drivers that influence past and present climate. This gives us an understanding of the variability of our climatic system, but we recognise that 130 years is not enough to understand the likelihood of extreme events, especially long-term droughts.
2. Paleoclimate data - using scientific methods, we are supplementing our historical record of climate conditions with new paleoclimate data (reconstructed from sources such as tree rings, cave deposits and coral growth). Combining these two elements gives us over 500 years of climate data.
3. Stochastic methods - we can then use a stochastic modelling method (based on the statistical characteristics of the new climate data) to help us quantify climate variability. This type of modelling tells us much more about possible climatic extremes and the natural variability in the climate.
4. Climate projections – we can then apply the NSW Government’s climate projections to this new data set to understand the impacts if climate change scenarios eventuate.

The figure below illustrates our approach. Also available to download in high resolution JPG, 847.58 KB.

This improved climate data will inform our river system models to gain a better understanding of water security and reliability risks faced by water users and the environment within each region. We will use the data to investigate the potential benefits and impacts of regional water strategy options. The data will also be used by WaterNSW and other agencies to assess the merits of new projects, plans and programs.

Read our frequently asked questions to find out more about the use of new climate data for the development of regional water strategies.

Expert panel says new method significantly advances our understanding of climate risk

The method was developed by the Department of Planning and Environment, with advice from the University of Newcastle and the University of Adelaide. We have commissioned a review of the method and its implementation by an independent panel of experts co-ordinated by the Office of the Chief Scientist and Engineer.

The panel found that the method is ‘fit for purpose’ in providing the best available knowledge of climate risk to inform NSW’s regional water strategies. They found that the method was consistent with best practice in the field and a major advance over using only historical records or only climate models. The expert panel noted that this is an area where the science is still developing. They recommended ongoing work to continuously improve the method and keep up to date with the latest scientific findings. The NSW Government is considering all their recommendations.

Our climate modelling approach

To help explain our new climate modelling approach we have developed a report that summarises the data we have used, and the way we have used it to develop new long-term datasets to represent a wide range of plausible climate events. We then use these datasets in our water planning models, which model the whole waterway system, including headwaters, storages, lakes, groundwater, and flows.

The new modelling shows that our water supplies in NSW could be less secure than we thought. By using paleoclimate data we have factored in that droughts longer than those of the last 130 years are likely at some point, and that we could see higher temperatures and less rainfall.

Climate analysis informs NSW’s regional water strategies report PDF, 4549.27 KB

Climate analysis informs NSW’s regional water strategies fact sheet PDF, 513.92 KB