Practice Note 12.1: Climate Change Impacts on the Useful Life of Infrastructure

This Practice Note 12.1 is a companion document to IPWEA Practice Note 12 (Useful life of infrastructure) and the two should be used together. Practice Note 12.1 (PN 12.1) provides a methodology and guidance for asset managers on how to assess the impact of climate change on infrastructure useful life to the year 2100.

The scope of PN 12.1 is to present: the expected changes in the climate across Australia to the year 2100; information on the likely primary impacts of those changes on asset usage, wear and tear – including physical damage and chemical deterioration; the range of adaptation responses that may be considered; sources of data and models available for more detailed climate and climate impacts assessments; and a range of supporting worksheets and information tables.

It does not provide information on secondary impacts such as technical or commercial obsolescence, legal responsibilities, or changes to the policy environment that would alter the useful life of an asset. The guide also assumes that the aspects of design, serviceability and maintenance of the asset remain unchanged over the period of its remaining useful life so as to focus on the impact that changes in the climate may have. Changes to the climate beyond 2100, although important, are not considered due to a lack of regional projections.

The Purpose of Practice Note 12.1

The purpose of this Practice Note 12.1 is to provide the necessary information and instruction to ensure that climate change impacts are incorporated into estimates of asset useful life. This will help entities obtain a more reliable annual depreciation expense and consequently more reliable operating results.

This Practice Note will provide users with an understanding of:

• the Asset and Climate Change Factors that need to be considered in estimating the impacts of climate change on the useful life of assets;
• the expected changes in the Australian climate to the year 2100;
• the likely impacts of those changes on asset materials and components;
• climate change adaptation and how it may affect the useful life of the asset;
• the process for estimating the impacts of climate change on a range of asset components using a Decision Tree Worksheet and supporting tables; and
• where to find further information about modelling the impacts of climate change on the useful life of high value assets.