Guest essay by Eric Worrall
According to the Australian CSIRO, Australia has already warmed by 1.4 ± 0.22C. But the CSIRO assures us bad things are happening, really. And they’re going to get worse. But they admit tropical cyclones have decreased, and while overall river flow is down, tropical wet season rainfall is up.
Australia’s climate has warmed
on average by 1.44 ± 0.24 °C since national records began in 1910, leading to an increase in the frequency of extreme heat events.
There has been a decline of around 16 per cent in April to October rainfall in the southwest of Australia since 1970. Across the same region May–July rainfall has seen the largest decrease, by around 20 per cent since 1970.
In the southeast of Australia there has been a decline of around
12 per cent in April to October rainfall since the late 1990s.
There has been a decrease in streamflow at the majority of streamflow gauges across southern Australia since 1975.
Rainfall and streamflow have increased across parts of northern Australia since the 1970s.
There has been an increase in extreme fire weather, and in the length of the fire season, across large parts of the country since the 1950s, especially in southern Australia.
Anomalies in annual mean sea surface temperature, and temperature over land, in the Australian region. Anomalies are the departures from the 1961–1990 standard averaging period. Sea surface temperature values (data source: ERSST v5, www.esrl.noaa.gov/psd/) are provided for a region around Australia (4–46 °S and 94–174 °E).
Australia’s climate has warmed since national records began in 1910. The oceans surrounding Australia have also warmed.
2 Report at a glance
There has been a decrease in the number of tropical cyclones observed in the Australian region since 1982.
Oceans around Australia are acidifying and have warmed by around 1 °C since 1910, contributing to longer and more frequent marine heatwaves.
• Sea levels are rising around Australia, including more frequent extremes, that are increasing the risk of inundation and damage to coastal infrastructure and communities.
In the coming decades Australia will experience ongoing changes to its climate. Australia is projected to see:
- Continued increases in air temperatures, more heat extremes and fewer cold extremes.
- Continued decrease in cool season rainfall across many regions of southern and eastern Australia, likely leading to more time in drought, yet more intense, short duration heavy rainfall events.
• A consequential increase in the number of dangerous fire weather days and a longer fire season for southern and eastern Australia.
• Further sea level rise and continued warming and acidification of the oceans around Australia.
• Increased and longer-lasting marine heatwaves that will affect marine environments, such as kelp forests, and raise the likelihood of more frequent and severe bleaching events in coral reefs around Australia, including the Great Barrier and Ningaloo reefs.
• Fewer tropical cyclones, but a greater proportion projected to be of high intensity, with large variations from year to year.
As someone who lives in a warm part of Australia, I’ve got to say 1.4C warming since 1910 does not feel like the end of the world.
There is substantial evidence Australia experienced warm spells in the 1800s comparable to today. 435 people died in a heatwave in 1894, a few years before the starting point of the CSIRO’s warming trend. Even more people died in the early 1900s (see the top of the page). JoNova has some information about extremely warm Australian temperatures recorded in the 1800s which the CSIRO and BOM usually seem to leave out when preparing climate reports.
If the drop in rainfall in the south is a genuine trend rather than just an example of Australia’s multi-decadal climate noise, the CSIRO has a solution on the drawing board which would drastically increase water availability for Australian farmers; a tropical megadam scheme which could capture some of that increased wet season rainfall, instead of continuing to allow it flow out into the sea.
If our politicians stopped frittering cash on renewables and pumped hydro schemes which cannot possibly have a measurable impact on global warming, there might be some money to spare to ensure water security for our farmers, regardless of any changes to Australia’s rainfall patterns.