Our climate has warmed by an average of 1.47℃ since national records began, bringing the continent close to the 1.5℃ limit that the Paris Agreement hoped would never be breached. When average global warming reaches this milestone, some of Earth’s natural systems are expected to suffer catastrophic damage.
The report, released today, paints a worrying picture of ongoing and worsening climate change. In Australia, associated impacts such as extreme heat, bushfires, drought, heavy rains and coastal flooding threaten our people and our environment.
The report is a comprehensive biennial snapshot of the latest climate trends, with a focus on Australia. It is compiled by the Bureau of Meteorology and the CSIRO, drawing on the latest national and international climate research.
It summarizes the latest science on Australia’s climate and builds on the previous 2020 report by including, for example, information from the Intergovernmental Panel on Climate Change’s most recent assessment report.
And the take-home message? Climate change continues unabated. The world is warming, sea levels are rising, ice is melting, wildfire weather is getting worse, flooding rains are becoming more frequent, and the list goes on.
What follows is a summary of the major findings in three key categories and an explanation of what it all means.
1. Heating, extreme temperatures and forest fires
The 2020 report said Australia’s climate has warmed by an average of 1.44℃ since national records began in 1910. That warming has now increased to 1.47℃. This mirrors trends in land areas around the world and brings with it more frequent extreme heat events.
2019 was the warmest year on record in Australia. The eight years from 2013 to 2020 are all among the ten warmest on record. Heating takes place both day and night and during all months.
Since the 1950s, extreme fire weather has increased and fire season has lengthened across much of the country. It has resulted in larger and more frequent fires, especially in South Australia.
Read more: What planting tomatoes shows us about climate change
2. Rain, floods and snow
In South West Australia, May to July rainfall has decreased by 19% since 1970. In South East Australia, April to October rainfall has decreased by 10% since the late 1990s.
This will come as somewhat of a surprise given the relatively wet conditions across eastern Australia in recent years. But don’t confuse long-term trends with year-to-year variability.
The lower rainfall has led to a reduction in the flow of the current; around 60% of water meters across Australia show a downward trend.
At the same time, heavy rainfall events are becoming more intense, a fact that has not gone unnoticed by flood-hit residents in Australia’s eastern states in recent months. The intensity of hour-long extreme precipitation events has increased by about 10% or more in some regions over the past few decades. This often leads to flash flooding, especially in urban environments. The costs to society are enormous.
Warm air can hold more water vapor than cooler air. That’s why global warming makes heavy precipitation events more likely, even in places where average precipitation is expected to decrease.
Also since the 1950s, snow depth and cover and the number of snow days have decreased in Alpine regions. The biggest dips occur in spring and at lower elevations.
Extremely cold days and nights are generally becoming less frequent across the continent. And while parts of southeast and southwest Australia have recently experienced very cold nights, it’s because the cool seasons have become drier and the winter nights clearer there, leading to more heat loss during the night.
Any camper will tell you how cold it can get on a clear, starry night, without the warm blanket of cloud cover.
Read more: As New South Wales reels, many wonder why it’s flooding in places where it’s never flooded before
3. Oceans and sea levels
Sea surface temperatures across the continent have risen by an average of 1.05℃ since 1900. The greatest ocean warming since 1970 has occurred off southeastern Australia and Tasmania. In the Tasman Sea, the rate of warming is now double the global average.
Ongoing ocean warming has also contributed to longer and more frequent marine heat waves. Marine heatwaves are particularly damaging to ecosystems, including the Great Barrier Reef, which is at risk of doom if nothing is done to address rising greenhouse gas emissions.
The oceans around Australia have also become more acidic and this damage is accelerating. The biggest change is occurring in the temperate and colder waters to the south.
Sea level is rising globally and around Australia. This is driven by both ocean warming and ice melting. Ice loss from Greenland, Antarctica and glaciers is increasing and will only get worse.
Around Australia, the greatest sea level rise was observed to the north and southeast of the continent. This is increasing the risk of flooding and damage to coastal infrastructure and communities.
What’s causing this?
All of this is happening because the concentrations of greenhouse gases in the Earth’s atmosphere continue to rise. The main driver of these gases is human combustion of fossil fuels. These long-lived gases form a “blanket” in the atmosphere that makes it harder for Earth to radiate the sun’s heat back into space. And so, the planet warms up, with very costly impacts for society.
The report confirmed that carbon dioxide (CO₂) has been building up in the atmosphere at an increasing rate over the past few decades. Worryingly, levels of methane and nitrous oxide have also risen very rapidly over the past two years.
What comes next?
None of these problems are going away. Australia’s weather and climate will continue to change over the next few decades.
As the report states, these climate changes are increasingly affecting the lives and livelihoods of all Australians. It goes on:
Australia needs to plan for and adapt to the changing nature of climate risk now and in the decades to come. The severity of the impacts on Australians and our environment will depend on how quickly global greenhouse gas emissions can be reduced.
This point is particularly sensitive, given the miserable failure of Egypt’s recent COP27 climate talks to build on pledges made by Glasgow just a year earlier to phase out fossil fuels.
Not surprisingly, then, the insurance industry is getting nervous about issuing new policies for people living on the front lines of climate extremes.
While the urgency to act has never been more urgent, we still hold the future in our hands – the choices we make today will decide our future for generations to come. Every 0.1°C of warming we can avoid will make a big difference.
But it’s not all bad news. Reengineering our energy and transport systems to be carbon neutral will create a whole new economy and job growth, with the added benefit of a safer climate future.
Do nothing and these state of the climate reports will continue to make for grim reading.
Read more: COP27 hesitant to phase out ‘all fossil fuels’. What’s the next step in the fight to keep them underground?