In southern Australia, for example, the frequency of heavy rainfall has decreased in some seasons. This is already being observed globally: heavy rainfall events over most land areas have become more frequent and intense in recent decades, although these trends have varied notably between regions and seasons. Source: Working Group for this document.īecause a warmer atmosphere contains more moisture, rainfall extremes are also expected to become more frequent and intense as global average temperatures increase. In the latter part of the record, the hot extremes threshold is exceeded progressively more frequently.
#Big weather pattern change series
The idealised temperature time series has similar variability throughout the whole record.
In this schematic illustration, the increase in average temperature is shown by the sloping line on the right. Since records began, the frequency, duration and intensity of heatwaves have increased over large parts of Australia, with trends accelerating since 1970.įigure 5.1: Temperature extremes change as average temperature increases. For example, in recent decades, hot days and nights have become more frequent, more intense and longer lasting in tandem with decreases in cold days and nights for most regions of the globe. These changes have already been observed.
In a warming climate, extremely cold days occur less often and very hot days occur more often (Figure 5.1). Human-induced climate change is superimposed on natural variability Nevertheless, some changes in Australia’s climate extremes stand out from that background variability. This high variability poses great challenges for recording and analysing changes in climate extremes not just in Australia, but the world over. These variations have existed for many thousands of years, and indeed past floods and droughts in many regions have likely been larger than those recorded since the early 20th century. With its iconic reference to ‘droughts and flooding rains’, Dorothea Mackellar’s 1904 poem My Country highlights the large natural variations that occur in Australia’s climate, leading to extremes that can frequently cause substantial economic and environmental disruption. by Charles Strebor Australia has a variable climate with many extremes How are extreme events changing? Flooding in Darwin, NT, following tropical cyclone Carlos in 2011.
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