Summary of the methodology used

The assessment focused on designing a high-resolution analysis of drought under climate change for NSW. This involved work to develop and then integrate three main components:

• the most recent climate change projection data (CMIP 6) were used given the need for higher quality projections of daily rainfall;
• the new high resolution (1km²) climate observation data; and
• the multi-indicator drought monitoring framework (Enhanced Drought Information System, EDIS) used in NSW for the 2017-2020 drought event.

The design of the scenarios in this study was a compromise between data availability in suitable climate projections and observations as well as providing drought projections that were broadly consistent with the Vulnerability Assessment. The final design used:

• a base period from 1995-2014 given the availability of quality climate observations.
• two future projection period 2041-60 and 2081-2100.
• two emissions scenario SSP 245 (equivalent to RCP 4.5) and SSP 545 (equivalent to RCP 8.5).

The resulting future drought scenarios for NSW are expressed as changes in key drought properties (duration and frequency) from a 1995-2014 baseline. This baseline is largely reflective of the lived experience of most land managers and includes part of the millennium drought sequence.