The Second Austrian Assessment Report on Climate Change (AAR2) provides a comprehensive scientific analysis of climate change spanning approximately 800 pages, showing ways to a sustainable transformation towards climate neutrality and a sustainable, just society.
More than 200 researchers from over 50 institutions spent more than three years working on this interdisciplinary report. IIASA’s Program Director Keywan Riahi and Senior Research Scholar Daniel Huppmann coordinated the report together with Harald Rieder (BOKU University) and Margreth Keiler (University of Innsbruck and Austrian Academy of Sciences, ÖAW).
The findings of the Second Austrian Assessment Report on Climate Change are clear:
- Since 1900, the temperature in Austria has risen by around 3.1°C – more than twice the global average.
- The frequency of extreme weather events such as heatwaves, droughts, heavy rainfall and mudslides is increasing, with significant consequences for health, infrastructure, agriculture and tourism.
- Reaching national and European climate targets is only feasible if substantial additional measures are implemented rapidly that go beyond already existing policies
- In the long term, preventative climate protection and adaptation measures are significantly more cost-effective than dealing with the damage caused by climate change.
© AAR2
“Climate change is no longer a distant threat; it is already impacting our daily lives. The new assessment report provides us with a scientific basis that demonstrates the extent of the changes already occurring in Austria, as well as the opportunities available to us to counteract them. The figures are clear, but they are not a reason to give up; rather, they are a clear call to action,” says Environment and Climate Minister Norbert Totschnig.
“This report is more than just a piece of scientific work; it also highlights potential solutions and tools. If we set the right course for environmental and climate policy, we can protect our homeland, ensure the long-term success of our economy, and guarantee a high quality of life for future generations. I would like to thank all the scientists who contributed to this report. They are providing facts and guidance for policymakers, businesses, and individuals. Now it is up to us to take on this responsibility together,” says Totschnig.
Austria’s vulnerability and IIASA’s scientific leadership
The country is particularly vulnerable to the effects of climate change, with risks and impacts increasing as the planet continues to warm up.
“The consequences of the climate crisis threaten our prosperity and exacerbate social inequalities here at home. The report outlines a wide range of actionable options and emphasizes that realistic, socially equitable and economically viable paths towards climate neutrality do exist. There are plenty of options, but they must be implemented quickly," says Margreth Keiler of the University of Innsbruck and the Austrian Academy of Sciences (ÖAW), which serves as the IIASA National Member Organization for Austria.
Beyond the coordinating role by Keywan Riahi and Daniel Huppmann, Wilfried Winiwarter and Thomas Schinko served as Coordinating Lead Authors of Chapters 4 and 8, respectively, and numerous authors contributed across the report.
The Second Austrian Assessment Report on Climate Change follows the structure and procedures of the reports by the Intergovernmental Panel on Climate Change (IPCC), including a thorough, multi-stage review process to ensure the highest scientific quality of the assessment. IIASA research group leaders Bas van Ruijven and Carl Schleussner acted as Review Editors to ensure that all comments by the external expert reviewers were answered and implemented appropriately.
Three early-career researchers at IIASA Maria Holzinger, Karl Scheifinger, and Verena Rauchenwald played an instrumental role in the report as a “Technical Support Unit”, providing scientific and administrative expertise to facilitate the writing process and coordinating an elaborate stakeholder process to ensure the relevance of the report.
IIASA co-chair Riahi on Austria’s climate targets
Austria's greenhouse gas emissions have fallen in recent years. Co-chair Keywan Riahi (IIASA) emphasizes that, per capita, emissions remain high by international standards.
“The measures currently being implemented are a step in the right direction, but they are not enough to achieve climate neutrality by 2040. If no further measures are taken, the reduction gap in 2030 will be up to 10 megatons of CO₂ equivalents in order to meet the targets agreed with the EU.”
The authors of the report agree that Austria can still achieve its emission reduction targets through measures that go beyond the currently implemented policies. However, Austria’s remaining carbon budget, based on the goals of the Paris Climate Agreement, is largely depleted.
“By contributing to the achievement of climate targets, Austria is also fulfilling its international obligations. Our report highlights the synergies between emission reduction, adaptation, and sustainable development,” says Riahi.
Transformation as an opportunity: insights from co-chair Huppmann
All sectors are called upon to act: “To achieve the climate targets, further effective measures must be implemented quickly,” emphasizes Daniel Huppmann.
“Key levers include the complete phase-out of fossil fuels, the rapid electrification of industry, transportation and heating systems, and a socially supported focus on the conscious use of resources. These measures are crucial not only for climate protection, but also for reducing Austria’s dependence on energy imports and, in turn, its vulnerability to global oil and gas price shocks.”
The report highlights synergies across many areas of society, such as the expansion of public transport and cycling infrastructure, building renovations, the transition to climate-friendly heating systems, urban greening to combat heat islands, protection of wetlands, climate-friendly diets, and adaptation in tourism and agriculture.
Rapid, far-reaching and cross-sectoral implementation of all these measures is crucial. The longer action is delayed, the smaller the scope for effective intervention becomes, and the greater the likelihood that the limits of adaptation will be reached.
Minister Totschnig on policy and technology
“The Second Austrian Assessment Report on Climate Change makes it clear that we need to use a variety of tools to achieve our climate goals. That’s why we are currently working intensively on a new Climate Act, which will provide a framework for joint cooperation,” says Totschnig.
“To reach our goals, we need to expand renewable energy and develop new technologies such as CO₂ storage, especially for sectors where emissions are difficult to avoid. This report provides the scientific basis for this approach. Now, we need to implement effective measures that are technologically, economically, socially, and sustainably sound,” Totschnig adds.
In detail: key findings of the report
Significant increase in extreme weather events and climate impacts
The temperature in Austria has increased by around 3.1°C above pre-industrial levels, which is significantly higher than the global average.
“Since the 1980s in particular, warming has intensified noticeably, with an increase of around 0.5°C per decade. This is reflected in a clear rise in extreme events, such as hot days and droughts, which are expected to increase in frequency in the coming decades, depending on emission levels. For example, extreme heat events could occur up to three times as often as they do today,” explains co-chair Harald Rieder from BOKU Vienna.
These changes are particularly noticeable in densely populated areas. Cities such as Vienna, Graz, Linz and Innsbruck are experiencing a sharp rise in heat stress. Without various measures being implemented, such as heat protection plans and adapted urban and spatial planning, the burden will continue to intensify.
Impacts on alpine regions
The effects of climate change are expected to intensify in alpine regions. Global warming is putting severe pressure on sensitive ecosystems, glaciers and permafrost in high-altitude areas.
"Due to more intense heavy rainfall, the risk of mudslides, flooding and landslides to settlements and infrastructure is increasing, while local adaptation capacities are often limited," emphasizes Margreth Keiler.
The decline in reliable snow cover poses significant structural challenges to large parts of the ski tourism sector. Depending on future emissions, the duration of snow cover at higher elevations is projected to decrease by a further 60–80 days by mid-century. Regions whose economies depend heavily on traditional winter sports risk long-term losses in value creation, employment, and regional development if targeted adaptation does not occur.
The stability and protective function of forests are also at risk. At the same time, rising temperatures are altering water availability in many regions.
The social dimension of climate change
Climate change does not affect all people equally.
“Climate change is more than an environmental issue – it affects our entire economic and social system. If we want to reduce emissions effectively, we also need to address social inequality and political capacity for action. The report shows that a just transition is not only possible, but also crucial to the success of climate policy,” says co-chair Daniel Huppmann.
Older people, individuals with low incomes and those living in precarious housing conditions are particularly vulnerable. Women, in particular, often face disadvantages due to the unequal distribution of unpaid care and domestic work. Meanwhile, the wealthiest ten percent of the population generate more than four times the emissions of the poorest ten percent and therefore contribute far more to climate change.
The costs of inaction exceed investments in climate protection and adaptation
Even today, Austria experiences damages amounting to around two billion euros annually due to the effects of global warming, such as heat, extreme weather events, stress on infrastructure and health impacts. Without effective climate protection and adaptation measures, these costs could rise to 10.8 billion euros per year by 2050.
Modeling shows that, in the long term, investments in climate protection and adaptation are significantly more cost-effective than inaction. Co-chair Harald Rieder emphasizes this point in particular:
“Forward-looking, systematically planned climate protection pays off – ecologically, economically, and socially. The climate crisis is no longer a future scenario; it is already a reality in Austria. Extreme weather events, heat stress, and resulting damage are already causing enormous costs. The report shows that if we act now, we can limit these risks and ensure economic stability. Climate protection is therefore an investment in prosperity, security, and quality of life. Our report provides a solid scientific basis for decisive societal action.”
The Second Austrian Assessment Report on Climate Change (AAR2) was funded by the Climate and Energy Fund using resources from the Federal Ministry for Agriculture, Forestry, Regions and Water Management, and Climate and Environmental Protection (BMLUK).
The following information can be found under this link: https://aar2.ccca.ac.at/en:
- Summary for Policymakers (SPM)
- the eight chapters of the report
- information on additional science communication and outreach activities
- simplified versions of SPM figures for media use
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