Examine the causes and consequences of the recent findings of Australia to have a warm winter this year.
According to the Bureau of Meteorology (BOM), Australia is supposed to witness its warmest winter in 2025 with a rise of about 2 degree celsius than normal, following a +1.54C anomaly in 2023 and +1.49 C anomaly in 2024.
Since last August, Australia has baked through a mean temperature 2.1 degrees Celsius above the baseline average from 1961-1990, which equates to a temperature about 2.5C above pre-industrial levels.
An abnormal consistent rise of temperature
Relative to temperatures in the early 20th century, the BOM’s forecast equates to an increase in temperatures of about 2C this winter.
Some of the important causes are:
- Abnormal heating of the land:
- A high pressure system has dominated over the south and southeast of Australia over the past few months.
- High pressure in the Tasman Sea can sometimes get stuck there for a few days. This leads to what’s known as “blocking”, when the usual passage of weather systems moving from west to east is obstructed. This can lock in weather patterns for several days or even a week.
- High pressure systems also tend to bring more clear and sunny conditions, which increases daytime temperatures in particular. Air in high pressure systems moves down towards the surface and this process causes warming, too.
- Australia sits between the Pacific and Indian Oceans and is subject to their variability, so we often look there to help explain what’s happening with Australia’s climate. In autumn though, our climate influences, such as the El Niño-Southern Oscillation and the Indian Ocean Dipole, are less active and have weaker relationships with Australian climate than at other times of year. Neither of these climate influences is in a strong phase at the moment.
- A significant decline in snow:
- The unprecedented heat during 2023 and 2024 brought two of the worst snow seasons on record, especially for lower resorts which struggled to retain a snow cover for more than a few weeks.
- The issue though in recent years, is not necessarily how much snow is falling, it’s the warm temperatures between snowfalls leading to rapid melting and rain.
- Abnormal heating of the sea:
- And it’s not just on land that unusual heat has been observed. The seas around Australia have been warmer than normal, causing severe coral bleaching to the west and east of the continent, harmful algal blooms and other ecosystem disruptions.
- In the absence of broadscale influences like El Niño or La Niña, the main contributor to the ongoing abnormal heat has been the local environment.
- The highest water temperatures compared to normal are currently off the west coast, up to 3C, and although anomalies will fluctuate in the coming months, modelling suggests the general pattern of ocean warmth will continue until at least mid-spring.
- The additional heat in the ocean helps to warm the layer of air just above the surface — which then leads to warmer winds blowing across land.
- When combined with already raised atmospheric temperatures from climate change, the consequence is the frequent temperature records observed during the past nine months.
- Certainly, the climate change:
- The elephant in the room is climate change. Human-caused climate change is increasing autumn temperatures and the frequency of late season heat events. As greenhouse gas emissions continue at a record pace, expect continued warming and a greater chance of autumn heatwaves in future.
- The effect of climate change on rainfall is less clear though. For the vast majority of Australia, there is high uncertainty as to whether autumn will become wetter or drier as the world warms.
Way forward:
- Countering climate change is the key – from simple strategies like afforestation to grand futuristic initiatives focussing on Green economy and Sustainable Development is the need of the hour.
- Being an island country, it is important to have warning systems and standard operating procedures in case of potential disasters due to this abnormal heating as adaptive measures are needed.
- Local solutions like cloud seeding can be promoted.
Source:
https://www.downtoearth.org.in/climate-change/its-almost-winter-why-is-australia-still-so-hot