Climate change science is about to become easier to use. Researchers from the International Institute for Applied Systems Analysis (IIASA) and partner institutions have developed a new climate impact taxonomy designed to turn the vast and highly technical findings of the Intergovernmental Panel on Climate Change (IPCC) into practical guidance for people making decisions about climate risk. The framework connects measurable changes in the physical climate—such as rising temperatures, drought, coastal flooding, and heavier rainfall—with the risks those changes create and the adaptation measures that can reduce them. Presented as a prototype “living tool,” the taxonomy could help transform global climate assessments into information that policymakers, planners, and climate service providers can apply to real-world problems.
The research, published in Nature Climate Change, addresses a long-standing challenge in climate communication. IPCC assessment reports contain an enormous body of evidence on climate processes, impacts, vulnerability, adaptation, and mitigation, but these areas are often presented in separate sections and at different levels of analysis. A policymaker assessing flood protection, for example, may need to navigate information about extreme precipitation, sea-level rise, exposure, infrastructure vulnerability, urban development, and adaptation limits across multiple chapters and reports. The new taxonomy offers a common structure for bringing those elements together, creating a direct pathway from a changing climate variable to a specific risk and then to possible responses.
At the center of the framework are the 35 climatic impact-drivers identified by the IPCC. These drivers describe physical changes in the climate system that can affect natural and human systems. They include gradual trends, such as increasing average temperatures, ocean warming, sea-level rise, and changes in precipitation, as well as extreme events, including heatwaves, intense rainfall, floods, droughts, wildfires, and tropical cyclones. By organizing these drivers systematically, the taxonomy helps users distinguish between the underlying climate signal and the consequences that emerge when that signal interacts with ecosystems, infrastructure, economies, and communities.
The taxonomy then links the climatic impact-drivers to eight representative key risks recognized in IPCC science. These risks encompass threats to ecosystems, human health and wellbeing, food and water security, infrastructure and critical services, cities and settlements, and other systems essential to society. The connections are not simply a list of hazards. Each one reflects a chain of cause and effect: a physical climate change can alter environmental conditions, those changes can affect an exposed system, and vulnerability can determine whether the result becomes a serious risk. The framework therefore provides a way to understand why the same hazard can produce very different outcomes in different places.
Each driver-risk connection is supplemented with information intended for practical use. The entries identify the scale at which impacts are likely to occur, the sectors or systems affected, examples of adaptation responses, and relevant links to mitigation. They also point users toward the IPCC chapters where the underlying scientific evidence is discussed. This design allows the taxonomy to function as both a navigation system and a knowledge map. A user interested in extreme heat and human health, for instance, could identify the relevant risk, examine the populations and systems most exposed, review adaptation options such as heat-health warning systems or urban cooling measures, and trace the information back to the scientific literature.
“This work is less about producing new climate science and more about making existing information actionable,” says lead author Michaela Werning, a researcher in the IIASA Energy, Climate, and Environment Program. She explains that the complexity and scope of IPCC reports can make them difficult to navigate, particularly for users who need to make decisions rather than conduct a comprehensive scientific review. By directly linking measurable climatic impact-drivers with risks and possible responses, the taxonomy is intended to provide a more accessible entry point without separating practical guidance from the scientific assessments on which it is based.
The analysis reveals several important patterns in the global landscape of climate risk. More than half of the hazard-risk combinations compiled by the researchers primarily unfold at regional scales. This finding highlights why climate impacts cannot be understood solely through global averages. Regional geography, infrastructure, ecosystems, socioeconomic conditions, and patterns of exposure can strongly influence the consequences of a given climatic change. A heatwave may intensify health risks in a densely populated city with limited green space, while drought may threaten food production in one region and hydropower generation in another. The regional emphasis also reinforces the need for adaptation strategies tailored to local conditions rather than copied uniformly across countries.
The taxonomy further shows an almost even division between gradual climate changes and extreme events. This balance challenges the tendency to associate climate adaptation mainly with disasters that arrive suddenly and visibly. Extreme heat, floods, storms, and fires require emergency preparedness and rapid response, but long-term changes in temperature, precipitation, sea level, and ecosystem conditions can quietly reshape risks over decades. Communities must therefore invest in both immediate resilience and long-range planning. Building codes, water management systems, agricultural practices, land-use decisions, health services, and infrastructure investments may need to account for climate conditions that are steadily moving beyond the range experienced in the past.
The timing of risk escalation provides another warning. Just under half of the driver-risk combinations assessed in the taxonomy are expected to reach high levels of risk at approximately 1.5°C of global warming, while a similar share reaches high risk only beyond 2°C. These thresholds are not universal tipping points; risk develops along different pathways depending on the hazard, location, exposure, vulnerability, and capacity to adapt. Nevertheless, the pattern demonstrates why mitigation and adaptation cannot be treated as alternatives. Rapid reductions in greenhouse gas emissions can limit the magnitude of future climate change, while adaptation can reduce the damage associated with impacts that are already unavoidable or worsening. The framework also identifies areas where evidence remains limited, helping researchers prioritize future studies and improve the reliability of climate-risk assessments.
The authors envision the taxonomy being used by climate service providers, adaptation planners, policymakers, and scientists. It could support customized risk dashboards, help planners compare response options, and clarify how emission reductions influence future risks across sectors. Its developers stress that the current version is a prototype and that its value will depend on continued testing, feedback, and refinement by both researchers and practitioners. “No single team has the expertise to cover the full breadth of climate impacts on its own,” says coauthor Alexander Nauels, a senior research scholar in IIASA’s Integrated Climate Impacts Research Group. The team is inviting users to challenge and improve the framework so that it can evolve into a shared language for climate action. As climate impacts become more frequent and decisions must be made under increasing uncertainty, that common language could help close one of the most important gaps in climate science: the distance between knowing what is happening and knowing what to do next.
Subject of Research: A climate impact taxonomy linking IPCC climatic impact-drivers, representative key risks, adaptation options, mitigation links, affected systems, and relevant scientific evidence.
Article Title: A climate impact taxonomy operationalizing IPCC physical driver and risk concepts
Web References: https://www.nature.com/articles/s41558-026-02717-7; https://www.iiasa.ac.at
References: Werning, M., Byers, E., Andrijevic, M., Schleussner, C.-F., Monteith, S., Aldrete Lopez, L., Lemaire, V., Matsumae, E., Thomas, A., and Nauels, A. (2026). “A climate impact taxonomy operationalizing IPCC physical driver and risk concepts.” Nature Climate Change. DOI: 10.1038/S41558-026-02717-7
Keywords: climate change, climate impacts, climate risks, adaptation, mitigation, IPCC, climatic impact-drivers, extreme heat, floods, drought, wildfire, sea-level rise, climate science, climate policy, resilience, climate services
