# Plenary Speaker: Georgina Falster: The role of Indo-Pacific SST variability in global drought occurrence

**URL:** <https://forum.access-hive.org.au/t/plenary-speaker-georgina-falster-the-role-of-indo-pacific-sst-variability-in-global-drought-occurrence/5105>\
**Category:** ACCESS Workshop Day 2\
**Created:** [25 August 2025 11:53 UTC](https://forum.access-hive.org.au/t/plenary-speaker-georgina-falster-the-role-of-indo-pacific-sst-variability-in-global-drought-occurrence/5105 "2025-08-25T11:53:13Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![lachlanswhyborn](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.access-hive.org.au/lachlanswhyborn/32/1837_2.png) [@lachlanswhyborn](https://forum.access-hive.org.au/u/lachlanswhyborn)\
**Post date:** [25 August 2025 11:53 UTC](https://forum.access-hive.org.au/t/plenary-speaker-georgina-falster-the-role-of-indo-pacific-sst-variability-in-global-drought-occurrence/5105/1 "2025-08-25T11:53:13Z")

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**The role of Indo-Pacific SST variability in global drought occurrence**  
  
Georgina Falster  
  
  
1. Sea surface temperature (SST) variability in the tropical Indian and Pacific oceans impacts the occurrence, duration, and intensity of droughts across the mid-latitudes. Palaeoclimate evidence suggests that in the first half of the last millennium, a ~30% reduction in the magnitude of Indo-Pacific SST variability (e.g., ENSO, IOD) coincided with increased frequency of multi-decade ‘megadroughts’ across the mid-latitudes. However, megadroughts are too rare even in the palaeoclimate record to test the robustness of this relationship.

1. We used ACCESS-ESM1.5 to examine the relationship between tropical Indo-Pacific SST variability and mid-latitude drought. We ran ACCESS-ESM1.5 with tropical Indo-Pacific SST variability prescribed to be 60% reduced, 30% reduced, 30% increased, or 60% increased relative to the existing ACCESS-ESM1.5 preindustrial control (500 years each).

2. The experiments were still running at the time of submission. A crude preliminary analysis indicates that drought length and intensity around south-eastern Australia is greater in the simulations with Indo-Pacific SST variability increased or reduced by 30% relative to the preindustrial. Increasing the magnitude of change to 60% in either direction resulted in shorter and less intense droughts.

3. ENSO and IOD enthusiasts, drought researchers, palaeoclimate researchers

4. ACCESS-ESM1.5, ENSO, IOD, drought, Australian hydroclimate  
  
  
Please use this thread for discussion about this plenary talk.

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**Author:** ![georgyfalster](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.access-hive.org.au/georgyfalster/32/2293_2.png) [@georgyfalster](https://forum.access-hive.org.au/u/georgyfalster)\
**Post date:** [5 September 2025 01:46 UTC](https://forum.access-hive.org.au/t/plenary-speaker-georgina-falster-the-role-of-indo-pacific-sst-variability-in-global-drought-occurrence/5105/2 "2025-09-05T01:46:16Z")

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Description of the experiment: [Experiment Proposal: Indo-Pacific pacemakers](https://forum.access-hive.org.au/t/experiment-proposal-indo-pacific-pacemakers/4227)

Thread describing initial set-up (see marked solution): [ACCESS-ESM1.5 in pacemaker mode](https://forum.access-hive.org.au/t/access-esm1-5-in-pacemaker-mode/4079)

payu configurations for the experiments: [GitHub - ACCESS-Community-Hub/access-esm1.5-sst-perturbation-indo-pacific: Magnitude of tropical Indian and Pacific ocean SST variability altered relative to ACCESS-ESM1.5 preindustrial control](https://github.com/ACCESS-Community-Hub/access-esm1.5-sst-perturbation-indo-pacific)