Expert opinion on the 2022-2023 Brisbane and Kimberley flood events and their relationship to anthropogenic climate change

The document argues that the 2022 Brisbane and 2022/23 Kimberley floods were made more likely and impactful by human-caused climate change, specifically through increased ocean temperatures, more frequent multi-year La Niña events, and higher atmospheric moisture. It concludes that while the frequency of some weather systems may decrease, the intensity of rainfall and flooding is expected to increase, potentially leading to prohibitive costs for protection and insurance in flood-prone zones.

• The 2022 Brisbane and 2022/23 Kimberley floods were driven by intense low pressure systems fueled by near-record ocean temperatures and a rare triple-year La Niña, both of which are linked to anthropogenic climate change. Using a causal networks approach, the author states it is 'exceptionally unlikely' that these events would have occurred as observed without the influence of climate change and the burning of fossil fuels.
• Anthropogenic warming increases atmospheric moisture via the Clausius-Clapeyron relation, where each degree Celsius of warming allows the atmosphere to hold an additional 7% more moisture. This provides more 'fuel' (heat and moisture) for extreme rainfall events, with observations in Australia showing short-duration extreme rainfall increasing by 8-10% per degree Celsius, and up to 18% for 1 in 100-year events in Brisbane and Sydney.
• While the total number of tropical cyclones in the Australian region has declined by at least 10% over the last 40 years, the proportion of high-intensity cyclones has increased. Global rainfall associated with these systems has increased by approximately 1.3% per year due to warming ocean and air temperatures.
• East Coast Lows (ECLs) are projected to decrease in frequency but increase in intensity. A study of the February-March 2022 floods showed that sea surface temperatures 2°C above average explained the increased intensity and a southwards shift in the position of the ECL.
• Future projections indicate that while the frequency of some flood-causing systems may decrease, those that occur will likely be more intense with higher peak flood levels. A modeled scenario at +3°C of global warming for the Brisbane region predicts 7-day rain totals exceeding 1600 mm and daily totals up to 900 mm, far exceeding the 2022 event.
• The cumulative impact of compounding, cascading, and concurrent climate events will be more significant than individual events. This increasing risk may eventually force communities to relocate from flood-prone zones as insurance and recovery costs become prohibitive.

APA

Watkins, A. B. (2026). Expert opinion on the 2022-2023 Brisbane and Kimberley flood events and their relationship to anthropogenic climate change. Earthjustice. https://earthjustice.org/wp-content/uploads/2026/06/annex-13-watkins.pdf

Chicago

Watkins, Andrew B. Expert opinion on the 2022-2023 Brisbane and Kimberley flood events and their relationship to anthropogenic climate change. Earthjustice, 2026. https://earthjustice.org/wp-content/uploads/2026/06/annex-13-watkins.pdf.

Wikipedia

{{cite report |last1=Watkins |first1=Andrew B. |title=Expert opinion on the 2022-2023 Brisbane and Kimberley flood events and their relationship to anthropogenic climate change |publisher=Earthjustice |date=5 June 2026 |url=https://earthjustice.org/wp-content/uploads/2026/06/annex-13-watkins.pdf |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{watkins2026expert, author = {Watkins, Andrew B.}, title = {{Expert opinion on the 2022-2023 Brisbane and Kimberley flood events and their relationship to anthropogenic climate change}}, institution = {Earthjustice}, year = {2026}, month = jun, url = {https://earthjustice.org/wp-content/uploads/2026/06/annex-13-watkins.pdf}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }