Science Source

Shifts in the seasonal distribution of deaths in Australia, 1968-2007

Examines the ratio of summer to winter deaths in Australia against a background of rising average annual temperatures over four decades: the ratio has increased from 0.71 to 0.86 since 1968
States that the same trend, albeit of varying strength, is evident in all states of Australia, in four age groups (aged 55 years and above) and in both sexes
Analysis of cause-specific mortality suggests that the change has so far been driven more by reduced winter mortality than by increased summer mortality
Comparisons of this seasonal mortality ratio calculated in the warmest subsets of seasons in each decade, with that calculated in the coldest seasons, show that particularly warm annual conditions, which mimic the expected temperatures of future climate change, increase the likelihood of higher ratios (approaching 1:1)
Results indicate that gradual climate change, as well as short-term weather variations, affect patterns of mortality