The Bureau of Meteorology has what is called it’s ‘ENSO Outlook’. It is an alert system for the El Niño-Southern Oscillation. In its design, it is like the fire danger indicators you see along Australian highways. However, the ENSO version has, at one extreme, La Niña, and at the other, El Niño, with alert levels ranging from ‘inactive’ in the middle to ‘watch’ to left or right and ‘alert’ as we get closer to those extremities1.
Currently the ENSO Outlook is at La Niña ‘Alert’, one setting removed from a full La Niña. This setting is due to continued cooling in the tropical Pacific Ocean and climate modelling showing that sustained La Niña conditions are very likely to persist over summer. In the past, when La Niña alert criteria have been met, as at present, a La Niña has developed about 70% of the time. La Niña events increase the chances of above-average rainfall for northern and eastern Australia during spring and summer2.
Climate change continues to influence Australian and global climate. So far, the global climate has warmed by about 1.1°C3, 4. However, Australia’s climate has warmed by around 1.44°C for the 1910–2019 period. Rainfall across northern Australia during its wet season (October–April) has increased since the late 1990s. In recent decades there has been a trend towards a greater proportion of rainfall from high intensity, short duration rainfall events, especially across northern Australia1. That translates to more flooding.
In addition to leading to an increase in short intense rainfall events, a La Niña tends to lead to cooler daytime temperatures south of the Tropic of Capricorn and warmer nighttime temperatures north of the tropic of Capricorn5. This made me wonder what are the chances that one or more of the morons in the Sky After Dark (SAD) asylum will use these cooler daytime temperatures to try to convince their gullible viewers that global warming isn’t happening. The warmer nighttime temperatures in the tropics will not register with them because, the SAD inmates are mostly ensconced in Melbourne rarely if ever travel north of Sydney. The reason I expect such climate denial outbursts to happen is because at least one of them did last summer6; it also happened to be a La Niña summer.