Using climate projections in an impact assessment

Chain of actions

To pursue the top-down part of an IAV assessment, there are a few underpinning principles, and a chain of actions to follow:

1. Before using climate projections, it is important to do relevant background reading, identify relevant stakeholders and determine the appropriate level of stakeholder engagement.
2. Next, determine the need/s for climate change data and information.
3. Obtain appropriate information and/or data (use the decision tree ).

The information from VCP19 and similar sources may be enough for basic purposes or raising awareness (the first branch in the decision tree), or it may be the start of further analysis. An initial assessment (sometimes called a ‘first pass assessment’ or ‘scan’) should be done before any detailed analysis. Following a scan, if more detailed information is needed then a detailed study can be scoped and carried out.

All IAV applications, including those in the water domain, should start with an assessment of past and future climate changes and the impact they have – this involves collecting and processing appropriate climate datasets from the Bureau of Meteorology, VCP19, CCIA and others, as well as data sets relevant to the application (e.g. databases of assets, networks and infrastructure).

Establishing plausible future climate conditions (scenarios or projections) is just one of many steps in knowing what climate change means to any application, and what to do in response. To assess the impacts, adaptation and vulnerability (IAV) aspects of future climate risk, we need to bring in other knowledge and information, and do further analysis.

Planning for managing future climate risk involves a combination of:

1. ‘Top-down’ analysis – starting by constructing climate projections and feeding them into a chain of analyses such as applied models to understand what this change in the climate means to a downstream application (e.g. feeding rainfall and evaporation into a runoff model to assess changes in water availability and river flows). This top-down chain may include a downscaling step to provide regional insights in the projected changes. The VCP19 project included downscaling for this purpose.
2. ‘Bottom-up’ analysis – assessing the vulnerability and resilience of systems, and pathways to reduce vulnerability and increase the capacity to cope or transform (without consideration of climate projections).