The report highlights the extent of coral reefs and associated biodiversity and ecosystems here in Australia that are either lost or degraded due to ocean warming and marine heatwaves.

We found that exceeding 1.5°C warming for several decades would result in severe and potentially irreversible impacts, especially in nature. We would see species extinctions and losses of entire ecosystems, such as tropical coral reefs and temperate kelp forests.

In Tasmania, our giant kelp forests represent a major foundational habitat for many species of cultural, recreational and commercial importance. However, climate-driven decline has seen 90 per cent of these kelp forests lost, while around Australia over 140,000 hectares of kelp species have been lost.

The Oceans chapter focused on the multi-faceted properties of the ocean being altered by climate change, and how marine ecosystems are responding to those complex changes.

Our climate extremes section then assessed the threats impacting life in terrestrial, ocean, polar and aquatic environments. My assessment focused on the oceanic regions and explored the mechanisms marine plants and animals use to adjust to stressors such as warming, acidification, less dissolved oxygen and fewer nutrients.

We found that it is challenging enough for marine life to adapt to just one environmental change, but this cumulative stress ramps up significantly when multiple changes are occurring at the same time. Punctuate those collective pressures with extreme events like marine heat waves, where the change is abrupt (over weeks) not gradual (over decades), and you have the perfect storm.

While it is possible for marine life to acclimate or adapt to the relatively slow, decadal pace of climate change, our assessment clearly demonstrates that, with the overlay of climate extremes which happen abruptly and with intensity, marine life must move or die.

To achieve sustainable development for all, mitigation measures and adaptations to climate change need to be integrated and undertaken in equitable and just ways.

We looked at the factors that drive decision making, including values and perceptions, power and influence, behaviour and incentives for action, and financial opportunities. And we assessed the risk and limits across multiple scales, institutions and systems.

Australia faces all of the key risks identified in this report. As part of the developed world, Australia has a special role to play in tackling the risks of climate change. Our region faces an extremely challenging future that will be highly disruptive for many human and natural systems.
 
Australia already has the tools and expertise available for reducing risks and supporting climate resilient development. This strong foundation can be used to engage with everyone, including Indigenous Peoples, to implement what is needed over the next decade.

The Australian Bureau of Agricultural and Resource Economics and Sciences recently estimated that changes over 2001 to 2020 reduced annual average farm profits by 23 per cent, or around $29,200 per farm, relative to 1950 to 2000.

The IPCC report has very high confidence that Australia’s ecosystems are experiencing, or are at risk of, irreversible change.

The most notable examples are in the oceans with more frequent and extensive coral bleaching events and the loss of temperate kelp forests due to ocean warming and marine heatwaves.

Extreme coastal flooding has increased due to sea-level rise superimposed upon high tides and storm surges. Rainfall intensity is also projected to increase.

We are seeing greater impacts from the interplay between climate variability and climate change over Australia. The likelihood of increasing rainfall intensity from climate change coupled with the impacts from La Niña events is deeply concerning, particularly in already flood prone areas.

Delaying climate adaptation and emission reductions will have more costly climate impacts for Australia and greater scale of adjustments needed.

The risks of increasing heat-related mortality and morbidity for people and wildlife is very real in Australia.

Climate change impacts are here, they matter, they are mostly negative but, if implemented, adaptation can take the edge off them. The latest IPCC report makes one thing crystal clear: adaptation policy, finance and practice have to be stepped up urgently if our systems are to keep pace with climate change. Adaptation action is a core foundation of sustainable development. Simply put, adaptation is key to maintaining our health, our industries and our environment.

Including climate change adaptation in all those decisions which are sensitive to climate change or sea-level rise can bring far more benefits than costs. And effective adaptation will lower risk and hence improve the investment environment. We can learn from climate change adaptation actions around the globe, including those implemented by indigenous peoples and through indigenous knowledge, and invest in the research and development that will give us new and better ways to adapt together.

Climate change is already changing Australia’s rainfall; that is, where it rains, when, and how much. We’re seeing more rainfall in the north, while in the south, droughts are becoming both more likely and severe. Climate change is also playing a major role in the drying trend underway in the southwest, affecting Perth and the wider region, from Geraldton down to Esperance.

Less rain means that there will be less streamflow into the water catchments that provide water for Australia’s capital cities, so we will need to think carefully about where our water comes from and how we use it.

The projected decrease of soil moisture and runoff means that there’s a greater likelihood of agricultural drought across Australia’s farming areas. Such changes are already reducing broadacre farm productivity and profitability. We’ve already seen how drier and hotter conditions can lead to increased bushfire risk, with climate change partly attributable for the fires across Australia during the summer of 2019/2020. And rising sea levels could lead to saltwater inundation of culturally significant sites and waterholes across northern Australia.

Ongoing climate trends have affected many extreme events. The Australian trends include further warming and sea-level rise, with more hot days and heatwaves, less snow, more rainfall in the north, less April-October rainfall in the south-west and south-east, and more extreme fire weather days in the south and east. Extreme events include Australia's hottest and driest year in 2019 with a record-breaking number of days over 39^oC, three widespread marine heatwaves during 2016-2020, three major floods in eastern Australia during 2019-2021, and major fires in southern and eastern Australia during 2019-2020.

Ongoing warming is projected, with more hot days and fewer cold days, further sea-level rise, ocean warming and ocean acidification. Less winter and spring rainfall is projected in southern Australia, with more winter rainfall in Tasmania, less autumn rainfall in south-western Victoria and less summer rainfall in western Tasmania, with uncertain rainfall changes in northern Australia. More droughts and extreme fire weather are projected in southern and eastern Australia. Increased heavy rainfall intensity is projected, with fewer tropical cyclones and a greater proportion of severe cyclones.

We found nine key risks. They include loss of coral reefs, kelp and alpine biodiversity, possible collapse of some forests in southern Australia, damage to low-lying coastal areas, a decline in agricultural production in southern and eastern Australia, an increase in heat-related deaths, cascading impacts for cities and infrastructure due to extreme events, and the inability of institutions and governance systems to manage climate risks.

The projected decline in future winter and spring rainfall in south-eastern Australia will be amplified in the decline in water resources. This exacerbates the already complex challenges of managing water for competing demands in this important region of Australia.

Climate change is projected to substantially reduce water resources in the Murray-Darling Basin. The future in the Basin will be hotter and drier, but there is considerable uncertainty around how much and by when, compounding the management and adaptation challenges.
 
The impacts of droughts over the recent decades, and projections of a drier future, have accelerated significant water policy reforms in particular the Basin Plan. These are positive adaptations as they help buffer the system against drought. But they can also be maladaptive by perpetuating unsustainable water and land use under ongoing climate change. In any case, more will need to be done, with the projected decline in water resources being potentially greater than the water recovered for the environment.

Australian crop yields are projected to decline due to hotter and drier conditions, including intense heat spikes. Interactions of heat and drought could lead to even greater losses than heat alone.

Across all types of agriculture, drought and its physical flow-on effects have caused financial and emotional disruption and stress in farm households and communities. To manage drought, balancing near-term needs with long-term adaptation to increasing aridity is essential.

Australian farmers, who are among the foremost risk managers globally, are adapting to drier and warmer conditions through more effective capture of non-growing season rainfall like stubble retention to store soil water, improved water use efficiency, and matching sowing times and cultivars to the environment to manage climate risk for their production.

Australian farmers are also adapting to changing climate through the application of new technologies that improve resource efficiencies, professional knowledge and skills development, new farmer and community networks, and diversification of business and household income.

CSIRO has been contributing to climate change adaptation through contributing to improved understanding and communicating climate-based risks in forest and agricultural systems; delivering climate-smart solutions for grains and other sectors including enhanced weather and seasonal climate forecasting; building risk and reward information tools that combine climate, systems modelling and environmental data for farmers and agribusiness; On farm – improving water use efficiency in broad acre farming; developing and testing strategies to improve productivity and profit-risk outcomes for growers; Long coleoptile genetics to improve wheat establishment with deep sowing to access out of season rain among many other initiatives.

CSIRO makes significant contributions to this area of work overseas as well (South – South-east Asia, Pacific Island countries in particular) working with Australian Government agencies such as the Australian Centre for International Agricultural Research, and Australian Water Partnership among others, sharing Australian expertise in managing climate risk.

Projected global warming under current global emissions reduction policies will leave many of our region's human and natural systems at very high risk and some beyond adaptation limits.

We’ve identified two emerging kinds of climate risk. One is the cascading and compounding impacts on cities, settlements, infrastructure, supply chains and services, due to events such as bushfires and heatwaves. And the other is the inability of institutions and governance systems to manage climate risks because the scale and scope of projected climate impacts may overwhelm the capacity to provide necessary policies, services, resources, and coordination to address the socio-economic impacts.
 
Some of our iconic ecosystems face the greatest risk from current and future climate change. The greatest risk is for the loss and degradation of coral reefs and associated biodiversity and ecosystem service values in Australia due to ocean warming and marine heatwaves.
 
Local government supported by state government is making impressive efforts to adapt to climate change and its impacts. Urban forests and irrigated vegetation are very good at reducing heat impacts and many local government areas have established targets for tree cover and integrated water management that can support healthy transpiring vegetation that can reduce temperature.
 
But even with further improvements in the adaptation process, our ability to adapt our way out of trouble will be severely compromised without rapid decarbonisation to limit warming.

This assessment has concluded that there is now even stronger evidence of the detrimental impacts of climate change on health and wellbeing, and particularly mental health. The report also clearly underlines the importance of considering the intricate and fundamental links between humans, ecosystems and society.

A new area of focus in the report is on cascading and compounding impacts – e.g. in Australia a severe drought was followed by the Black Summer fires of 2019/2020, which was then followed by floods in parts of the country. The impacts of these climate hazards affect our ability to recover, as often there is little time between their onset.

Many risks for human health and wellbeing could be reduced and some potentially avoided if we reduce our greenhouse gas emissions and strengthen our adaptation responses, particularly so that these are proactive and rapid. Rapid transformations are needed to ensure that we develop in a way that is climate resilient and sustainable.

For the health sector, this means universal access to primary healthcare, including mental health care. Investing in other sectors such as agriculture, food, energy also play a key role in reducing vulnerability to climate-related health risks. These transformational changes will be more effective if they are responsive to regional, local knowledge and Indigenous Knowledge.

In the newly-released IPCC WGII report, scientists document thousands of impacts to ocean and coastal ecosystems caused by global warming, sea-level rise and ocean acidification. These are not impacts that await us in some dystopian future, but impacts we have already seen. Coastal ecosystems have borne the brunt of climate change so far, because this is where people most directly interact with marine biodiversity, and where human impacts other than climate change make climate impacts worse. But extensive new scientific evidence in the IPCC report shows that if we reach 1.5°C warming, climate impacts will escalate rapidly, and that some of these impacts will become irreversible for generations, if not centuries.

This is especially pertinent because the IPCC late last year concluded that we stand a very good chance of reaching 1.5°C within the next 20 years, or earlier if we don’t start treating climate change as an urgent priority. Ecosystems like coral reefs, mangroves, salt marshes and seagrass meadows are at particular risk, as are the services that these ecosystems deliver to society. Given the large proportion of the world’s population that lives along coastlines, this is a serious concern. And more so for those who rely most directly on ecosystems for livelihoods and sustenance.

As long as we remain below 1.5°C of warming, there are things we can do to help people and nature deal with the changing climate. This is called adaptation. For the coast and sea, adaptation centres around carefully-planned, effective and socially fair management of at least 30 per cent of the global ocean. And this is important because a healthy planet is essential for resilient societies. Although projected impacts at 1.5°C of warming are worrying, at higher levels of warming, potential impacts are worse. And the greater the warming and the longer it lasts, the less chance there is of reversing the resultant impacts in the future.

Technology might be able to curb or even reverse greenhouse gas emissions, and control future global temperatures, but it is unlikely to be able to undo the damage that climate change has wrought. Given that we so far have not done enough to counter climate change, we have to accept that the 1.1°C of warming we have caused will result in some impacts we can’t avoid. But there is still an opportunity to avoid the worst. Although, the window of opportunity is closing fast, the quicker we are to take serious action, the greater the benefits will be for the people of the world.

I am a public health researcher from the University of Queensland and a Lead Author in the regional chapter focused on Australia and New Zealand (chapter 11).

My relevant research background is about how climate change impacts human health, how Indigenous Peoples’ Knowledge is an important contributor to responding to climate change, the on-ground impacts of climate change in remote Indigenous communities in Australia, and issues of remote drinking water supplies in a changing climate. These were the main chapter sections to which I contributed.
 
Climate change action aligns with the efforts of public health, where the focus is on prevention of ill health and the prolonging of good health and wellbeing – in large part through the organised efforts of society. This IPCC report emphasises the need for strong governance, long-term investments to change, and equity across society in all climate responses. This will reduce risks by better managing identified hazards and vulnerabilities. Projected extreme impacts can be reduced in likely occurrence through better planning and a long term approach.
 
Our chapter recognises that Indigenous Knowledges can enhance effective adaptation through the passing down of knowledge about climate change planning that promotes collective action and mutual support. As a non-Indigenous Australian, I have valued the involvement of Indigenous researchers as contributing authors; this includes Professor Sandra Creamer, Associate Professor Bradley Moggridge, Dr Vinnitta Mosby and Darren King. They have brought First Nations’ perspectives from their Countries from mainland Australia, the Torres Straits and Aotearoa/New Zealand.