Australia’s Tinderbox Drought: An extreme natural event likely worsened by human-caused climate change

Science Advances, Journal Year: 2024, Volume and Issue: 10(10)

Published: March 6, 2024

We examine the characteristics and causes of southeast Australia's Tinderbox Drought (2017 to 2019) that preceded Black Summer fire disaster. The was characterized by cool season rainfall deficits around -50% in three consecutive years, which exceptionally unlikely context natural variability alone. precipitation were initiated sustained an anomalous atmospheric circulation diverted oceanic moisture away from region, despite traditional indicators drought risk Australia generally being neutral states. Moisture intensified unusually high temperatures, vapor pressure deficits, reductions terrestrial water availability. Anthropogenic forcing 18% with interquartile range 34.9 -13.3% highlighting considerable uncertainty attributing droughts this kind human activity. Skillful predictability possible incorporating multiple remote local predictors through machine learning, providing prospects for improving forecasting droughts.

Language: Английский

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Non-stationarity in extreme rainfalls across Australia

Journal of Hydrology, Journal Year: 2023, Volume and Issue: 624, P. 129872 - 129872

Published: June 27, 2023

Future flooding is likely to exceed current design flood levels which are based on historical extreme rainfall characteristics. The Clausius-Clapeyron relationship explains the intensification of rainfalls as approximately 7% per one degree warming atmospheric water holding capacity increases with temperature. Therefore, prepare for a future warmer climate, we need develop methodologies project intensities across range durations and exceedance probabilities used in engineering design. However, studies that have investigated changes Australia had disparate results not spatially or temporally comprehensive – hampering our understanding different probabilities. This study investigates impact climate change from annual maximum 1 100-year storm continent Australia. We find short duration (<1 hour) greater than long (>1 maxima 1967 2021. These consistent regardless data period set chosen analysis. estimate events rarer through fitting non-stationary Generalize Extreme Value models. severity increased more frequent events. Further, identify parameterisation model location scale parameters capture historic quantiles physical intensification, empirical quantile trends. conclude trends best represented by models incorporate both parameters, solely varying either parameters.

Language: Английский

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Linking ENSO to Synoptic Weather Systems in Eastern Australia

Geophysical Research Letters, Journal Year: 2023, Volume and Issue: 50(15)

Published: Aug. 8, 2023

Abstract El Niño‐Southern Oscillation (ENSO) is the main driver of interannual east Australian rainfall variability, but its link with rain‐producing synoptic weather systems unclear. By tracking low pressure in ERA5 over 1979 to 2021, we find that springtime cyclones are linked variations large‐scale atmospheric circulation during ENSO events. On spring days a cyclone La Niña, dipole occurs strong anticyclonic anomaly southeast Australia and cyclonic eastern Australia. The northeasterly directs tropical moisture toward Australia, coupled induced ascent, promotes this region. Both dynamical thermodynamical changes important for response. An almost opposite response on Niño events: high‐pressure continent reduces These setups resemble seasonal‐mean Rossby wave teleconnections, indicating between ENSO.

Language: Английский

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Modelling non-stationarity in extreme rainfall using large-scale climate drivers

Journal of Hydrology, Journal Year: 2024, Volume and Issue: 636, P. 131309 - 131309

Published: May 10, 2024

Flood estimates used in engineering design are commonly based on intensity–duration–frequency (IDF) curves derived from historical extreme rainfalls. Under global warming these rainfalls increasing, threatening the capacity of existing infrastructure to resist failure as IDF traditionally assume no change rainfall magnitude. Hence, there is a need investigate implications non-stationarity derive IDFs across storm durations and annual exceedance probabilities (AEPs). One way doing this incorporate covariates into fitted probability distribution. However, few studies which examine using large-scale climate drivers covariates, with little consensus covariate most appropriate. Here we evaluate different durations, 1 2 AEP 100 AEP, potential including continental mean temperature, diurnal temperature range, dewpoint precipitable water, Indian Ocean Dipole, El Niño Southern Oscillation, Annular Mode. These linked three parameters Generalized Extreme Value distribution identify appropriate form non-stationary model. We analyse 16 6 min 7 day maxima 46 stations Australia. Based Akaike Information Criteria, water superior at large proportion irrespective duration. when modelled quantile changes inspected, only able adequately capture variability both duration probability. Further, regional average values were was improvement model performance compared continental-wide particularly for short durations. The results show that stationary underestimated by 12 % – 9 frequent (1 5 AEP) 23 13 rare (6 30 min) events. Moving forward our suggests needs ensure flood planning levels not under-designed.

Language: Английский

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Decadal Trends in Surface Elevation and Tree Growth in Coastal Wetlands of Moreton Bay, Queensland, Australia

Estuaries and Coasts, Journal Year: 2024, Volume and Issue: 47(7), P. 1955 - 1971

Published: Jan. 19, 2024

Abstract Coastal wetlands surrounding urban environments provide many important ecosystem services including protection from coastal erosion, soil carbon sequestration and habitat for marine terrestrial fauna. Their persistence with sea-level rise depends upon their capacity to increase surface elevation at a rate comparable the of rise. Both sediment organic matter plant growth contribute gains in elevation, but importance these components varies among sites variation climate over long time scales, which monitoring is seldom available. Here, we analysed accretion mangrove tree 15 years Moreton Bay, Queensland, Australia, period that spans El Niño/La Niña (ENSO) cycle, strongly influences rainfall sea level region. Piecewise structural equation models were used assess effects biotic (tree growth, cover bioturbation by invertebrates) environmental factors on annual increments throughout this period. Our model mangroves identified both positively influenced rainfall, was not, thus, higher levels compaction profile high rainfall/high inferred. In contrast, our saltmarsh found gains. Declines species composition mangrove, loss occurring forests dominated Avicennia marina compared those proportion Rhizophora stylosa . Decadal-scale ENSO affected trends more conditions than although (mangrove bioturbation) observed. Further research into tipping points extreme events (either La or Niño low levels) will help clarify future distribution within Bay.

Language: Английский

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Tropical pastures add value to grazing systems in temperate environments of Eastern Australia

Field Crops Research, Journal Year: 2024, Volume and Issue: 312, P. 109402 - 109402

Published: May 1, 2024

Australia has tropical, summer dominant rainfall in the north transitioning to temperate, winter south. Temperate pasture species with a cool season growth pattern are commonly grown south, but tropical that highly productive and responsive rainfall, may also have role southern systems climate change. Determine value of replacing temperate pastures pastures; assess emergence success grasses response historic change eastern Australia. The AusFarm model was used test lucerne (Medicago sativa L.) (L); annual ryegrass (Lolium rigidum L.)/subterranean clover (Trifolium subterraneum (RC); or lucerne/annual ryegrass/subterranean (LRC) at varying rates inclusion five locations across subtropical-temperate transition zone. bare fallow, short fallow increased ground cover management tested. modelling covered two periods, Far Climate (1960–1990) Near (1990–2020). Tropical had higher plant late summer-early autumn when less active. Pasture decreased from period all sites. L lost most production over this period, minimal other types. Supplementary feeding reduced sites pastures. cost supplementary by $20/ha variability between years, which in-turn gross margin an average $26/ha. improved profitability on $24/ha (11%), different responses environments. At low (Condobolin Leeton) there substantial benefit grass-clover (TC) replaced L, (Cowra Wagga Wagga) RC TC. There gradient successful very high (>90%) north, opportunities south (<45%), marginal influence sowing management. Adding grazing summer-autumn growth, animal requirements met pasture, margins. Profitability livestock change, can be overcome optimising composition. Fewer years favourable for establishment more environments, therefore strategies need adjusted field

Language: Английский

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Machine Learning Identification of Attributes and Predictors for a Flash Drought in Eastern Australia

Climate, Journal Year: 2024, Volume and Issue: 12(4), P. 49 - 49

Published: April 8, 2024

Flash droughts (FDs) are natural disasters that strike suddenly and intensify quickly. They occur almost anywhere, anytime of the year, can have severe socio-economic, health environmental impacts. This study focuses on a recent FD began in cool season Upper Hunter region Eastern Australia, an important energy agricultural local global exporter is both flood- drought-prone. Here, authors investigate started abruptly May 2023 extended to October 2023. The followed floods November 2021 much above-average May–October 2022 rainfall. Eight machine learning (ML) regression techniques were applied 60 periods from 1963–2022, using rolling windows attribution search 45 possible climate drivers, individually combination. six most prominent likely predictors, provide understanding major contributors FD. Next, 1963–2022 data divided into two shorter timespans, 1963–1992 1993–2022, generally accepted as representing early accelerated warming periods, respectively. key attributes markedly different for timespans. These differences readily explained by impacts hemispheric synoptic-scale atmospheric circulations.

Language: Английский

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Novel climate analysis methods applied to the Australian ESCI projections data

Frontiers in Climate, Journal Year: 2025, Volume and Issue: 6

Published: Jan. 3, 2025

This study examines several methods and new ideas for climate analysis, including expanded ensembles, that combine model projections from different greenhouse gas emissions pathways time periods. These are tested on Australian data previously made available based outputs the Energy Sector Climate Information (ESCI) project included all dynamical downscaling approaches with bias correction designed attention to detail extremes. The ensemble method provides larger sample sizes help enhance confidence, results showing projected changes per degree of global warming have relatively small differences when calculated using two emission periods, smaller than variations between individual models in ensemble. Results include maps mean values extremes temperature rainfall metrics, as well compound events associated dangerous bushfire weather conditions, providing insights change Australia. also show extremely fire conditions such those Black Summer 2019/2020 Saturday February 2009 currently still very rare, but has already increased chance their occurrence, increases future higher amounts emissions. New analysis is presented rainfall-based metrics agriculture biogeography Goyder’s Line, discussed relation use analogues adaptation decision making.

Language: Английский

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Sub-seasonal to seasonal drivers of regional marine heatwaves around Australia

Climate Dynamics, Journal Year: 2024, Volume and Issue: unknown

Published: April 19, 2024

Abstract As marine heatwaves (MHWs) become more intense and longer lasting due to global warming, understanding the drivers impacts of these events is crucial for effective resource management. This study investigates influence El Niño Southern Oscillation (ENSO), Indian Ocean Dipole (IOD), Annular Mode (SAM), Sub-Tropical Ridge High (STRH), Madden Julian (MJO) on sea surface temperature (SST) anomalies MHWs around Australia. The aim this research improve our sub-seasonal seasonal (S2S) timescales, which bridges gap between short-term weather interannual long-term climate variability. By analysing SST characteristics during specific driver phases, a simple MHW hazard index developed. Our findings support previous indicating that La Niña plays role in driving off coast Western Australia reveals previously unrecognised connection ocean warming Queensland Tasman Sea low-pressure systems associated with negative phase STRH. emphasizes importance considering multiple their compounding effects by showing significant changes typical patterns additional MJO. acting S2S timescale, forecasts can accurately capture timing, intensity, spatial extent within season. These improved enhance ability managers adapt allocate resources based evolving conditions, enabling implementation harm minimisation strategies.

Language: Английский

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An overview of observed changes in precipitation totals and extremes over global land, with a focus on Africa

Earth-Science Reviews, Journal Year: 2025, Volume and Issue: unknown, P. 105063 - 105063

Published: Feb. 1, 2025

Language: Английский

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