The latest State of the Climate report is out, and there’s not much good news for Australians.
Our climate has warmed by an average of 1.47℃ since national records began, bringing the continent closer to the 1.5℃ limit that the Paris Agreement hoped would never cross. 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 CSIRO, drawing on the latest national and international climate research.
It synthesizes 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 latest assessment report.
And the take-home message? Climate change continues unabated. The world is getting warmer, sea levels are rising, ice is melting, fire weather is getting worse, torrential rains are becoming more frequent – and the list goes on.
What follows is a summary of the main results in three key categories – and an explanation of what it all means.
1. Global warming, extreme heat and bushfires
The 2020 report says Australia’s climate has warmed by an average of 1.44℃ since national records began in 1910. That warming has now risen to 1.47℃. This mirrors trends in terrestrial regions of the world and results in more frequent extreme heat events.
2019 was Australia’s hottest year on record. The eight years from 2013 to 2020 are all among the ten warmest on record. Warming occurs both day and night, and throughout the months.
Since the 1950s, extreme fire weather has increased and the fire season has lengthened in much of the country. This has led to larger and more frequent fires, particularly in southern Australia.
Read more: What planting tomatoes teaches us about climate change
2. Rain, floods and snow
In southwestern Australia, rainfall from May to July has fallen by 19% since 1970. In southeastern Australia, rainfall from April to October has fallen by 10% since the end of the 1990s.
This will be somewhat surprising given the relatively wet conditions in eastern Australia over the past few years. But don’t confuse longer-term trends with year-to-year variability.
The decrease in precipitation has led to a reduction in the flow of rivers; around 60% of water gauges around Australia show a declining trend.
At the same time, the heavy rains are getting more and more intense – a fact that has not gone unnoticed by flood-stricken residents in Australia’s eastern states in recent months. The intensity of extreme precipitation events lasting one hour has increased by about 10% or more in some areas in recent decades. This often leads to flash flooding, especially in urban settings. The costs to society are enormous.
Warm air can hold more water vapor than cooler air. This is why global warming makes heavy rain events more likely, even in places where average rainfall is expected to decrease.
Also since the 1950s, snow depth and cover, as well as the number of snow days, have decreased in the Alpine regions. The largest declines occur in spring and at low elevations.
Extremely cold days and nights are generally becoming less common on the mainland. And while parts of south-eastern and south-western Australia have recently experienced very cold nights, it’s because the cool seasons have become drier and winter nights clearer there, causing more heat loss at night.
Any camper will tell you how cold it can be on a clear starry night, without the warm blanket of cloud cover.
Read more: As NSW spins, many wonder why it’s flooding places it’s never flooded before
3. Oceans and sea levels
Sea surface temperatures around the continent have risen by an average of 1.05℃ since 1900. The greatest warming of the oceans since 1970 has occurred southeast of Australia and Tasmania. In the Tasman Sea, the rate of warming is now double the global average.
The continued warming of the oceans has also contributed to longer and more frequent marine heat waves. Marine heat waves are particularly damaging to ecosystems, including the Great Barrier Reef, which is at dangerous risk of ruin if nothing is done to combat rising greenhouse gas emissions.
The oceans around Australia have also become more acidic and this damage is accelerating. The biggest change is in the temperate and cooler waters to the south.
Sea levels are rising globally and around Australia. This is due to both warming oceans and melting ice. Greenland, Antarctica and glacier ice loss is increasing and getting worse.
Around Australia, the highest sea level rise has been observed in the north and southeast of the continent. This increases the risk of flooding and damage to infrastructure and coastal communities.
What causes this?
All of this is happening because the concentrations of greenhouse gases in the Earth’s atmosphere continue to rise. The primary driver of these gases is the human combustion of fossil fuels. These long-lived gases form a “blanket” in the atmosphere that makes it harder for Earth to radiate heat from the Sun back into space. And so, the planet is heating 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, over the past two years, methane and nitrous oxide levels have also increased very rapidly.
What happens afterwards?
None of these problems go away. Australia’s weather and climate will continue to change over the coming decades.
As the report indicates, these climate changes are increasingly affecting the lives and livelihoods of all Australians. It continues :
Australia must 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 difficult, given the dismal failure of the recent COP27 climate talks in Egypt to build on pledges made in Glasgow a year earlier to phase out fossil fuels.
So it’s no surprise that the insurance industry is getting nervous about issuing new policies to people living on the front lines of climate extremes.
While the urgency to act has never been greater, we still hold the future in our hands – the choices we make today will decide our future for generations to come. Every 0.1℃ of warming we can avoid will make a big difference.
But it’s not all bad news. Re-engineering our energy and transport systems to be carbon neutral will create a whole new economy and job growth – with the added bonus of a more secure climate future.
Do nothing, and these state-of-the-climate reports will continue to read bleakly.
Read more: COP27 balked at phasing out ‘all fossil fuels’. What’s next in the fight to keep them in the ground?
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