According to Australia’s Bureau of Meteorology (BoM) recent statement, 2024 was the country’s second warmest since 1901. This did not come as a surprise as the World Meteorological Organization (WMO) on January 10 declared last year as the warmest year on record.
Here is a look at how temperatures have been rising over Australia in recent years, and what has been the impact of this trend.
Rising temperatures
Since 1901, Australia’s average temperatures have increased by 1.51 degrees Celsius. The year 2019 was its warmest ever on record — eight of the warmest years that the country experienced were between 2013 and 2024.
As a result, the annual number of hot days is also increasing in Australia. Meanwhile, the number of cold days and nights has dipped.
Much like the rest of the world, Australia’s land cover is showing a faster warming rate than the surrounding oceans. In numbers, the land has been warming 40% faster than the ocean.
Change in rainfall patterns
The Indian Ocean Dipole (IOD) — a significant ocean phenomenon that affects India’s weather systems — and the El Niño Southern Oscillation (ENSO) — with its warm ( El Niño) and cool (La Niña) phases — influence the rainfall and its variability or distribution over Australia. Rainfall between April and October is significant as it is directly linked with the country’s cultivation activities, and recharge of groundwater water.
Long-term rainfall trends have depicted a fall in the rainfall quantum during this cool season, particularly along the country’s southwest and southeast regions. In the southwest region, a drop of 20% in rainfall has been realised since 1970 compared to the rainfall average of 1900-1969.
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Since 1994, the decline in rainfall between May and July has stood at 24%. The overall declining rainfall is associated with shifting weather patterns, higher-than-normal surface atmospheric temperatures, and fewer low-pressure systems bringing rainfall.
In contrast, northern Australia has been experiencing increased rainfall since 1994. Climate change is pushing heavy and short-spell events leading to massive flooding in Australia. In recent decades, there has been a 10% rise in such rainfall spells. Thunderstorm-led intense rainfall spells have risen since the 1970s as opposed to such rainfall associated with low-pressure systems.
Warming seas
The ocean around Australia has been warming at an alarming rate. Data suggest that since 1900, the sea surface temperature (SST) in the Australian region has warmed by 1.08 degrees Celsius.
The highest that the average SST spiked was in 2022, and the event was associated with a negative phase of the IOD. As a result, the intensity and frequency of marine heatwaves (MHWs) have been impacted. MHWs also now last longer, sometimes even for months in a row. Last month, MHWs led to the death of more than 30,000 fish in this region. Notably, the water mass around Australia has been warming faster than its counterparts.
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Future of climate
The BoM has predicted a continuation of rising atmospheric temperatures alongside a significant rise in heat extreme events. Droughts, owing to a reduction in the rainfall during cooler months (April-October), will be more pronounced in the coming decades.
Rainfall events involving short but extremely heavy spells will become more common.
Warming sea and rise in sea levels will be at an accelerated pace in addition to the ocean acidification around Australia.
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The chances of increased events of MHWs are on the cards, which will directly affect marine habitats such as kelp forests and corals. Even though the number of tropical cyclones has been on a decline, the ones forming would be intense, capable of barrelling into coasts with heavy pounds of rainfall.
The snow cover shall further shrink along the alpine regions.