Evaluation of the Heat Early Warning System in Styria, Austria

Abstract

Heat-health early warning systems are increasingly adopted as adaptation measures to reduce the health impact of heatwaves. Styria was the first Austrian state to implement such a system in 2011, but its effectiveness had remained unassessed. This study employs a difference-in-differences approach to quantitatively evaluate the impact of the Styrian heat early warning system on all-cause mortality and morbidity and finds no detectable effect. In addition, mixed methods are used to examine factors that may influence the plan’s effectiveness. The Styrian heat early warning system is found to display a sensitivity of only 44%, indicating that warnings are not issued for the majority of heatwave days. Interviews reveal substantial discretion exercised by agency staff in issuing warnings, raising concerns regarding the usefulness and validity of the warning threshold defined by the Heat Protection Plan. While further research is needed to clarify the relationship between heat and health outcomes in Styria and to assess the warning system’s full impact, this study recommends updating the Styrian Heat Protection Plan to reflect how warnings are being used, closing the gaps between policy and practice, and to include mechanisms for data collection to support ongoing monitoring and evaluation.

Popular Abstract

Warning without impact? Evaluation of Styrian heat early warning system shows no effect

Many look forward to the warmth of summer and cherish their memories of soaking up the heat by a pool or lake. However, too much heat stress leads to dangerous health complications, some of which can be deadly. In fact, heatwaves have been found to be the deadliest among all climate-related disasters, causing thousands of deaths across Europe every year. Evidence of this dangerous effect of summer heat has been found in the Austrian state of Styria as well, suggesting that steps should be taken to protect the population from high temperatures. This is especially true given that temperatures are expected to rise in the coming years as our climate is changing.
Although Styria has launched various programs, including a heatwave early warning system to alert authorities and other stakeholders to dangerously hot conditions, their effectiveness has not yet been assessed. While similar measures have worked well in other regions, the effects of heat and of warning systems can vary significantly from place to place. To know whether the Styrian early warning system works as intended, it therefore had to be evaluated. Such an evaluation could not only help adjust the system to better protect Styrians from heat, but also allow other regions–who might base their own policies on the Styrian one–ensure that their warning systems are based on effective measures.
However, when deaths, hospital admissions, and ambulance transportation rates in Styria were examined, no effect of the early warning system could be found. This may be due either to the warning system not functioning as intended, or because not all factors influencing the impact of heat were accounted for in the study. The effects of the early warning system thus remain unclear, and more work is needed to fully understand how heat affects Styria and how the state’s warning system might affect different parts of its population. Although some argue that warning systems might still contribute to an overall adaptation to changing temperatures–for example by raising awareness of heat-related health impacts–the absence of any measurable impact on human health is a serious issue if such warning systems are meant to protect the public from serious harm. This study therefore also looked at factors that could influence the effectiveness of the Styrian warning system.
While the system was found to be well-designed in many ways–being simple, well established, and well accepted among its stakeholders–two potential issues were identified. Warnings were issued based on more factors than stated in the official document, leading to a lack of transparency in how the system functions, and further complicating evaluations. Moreover, no specific provisions had been made for regular monitoring or evaluation of the early warning system. This meant that relevant data were at times not collected at all, or not in the quality necessary to allow for a thorough evaluation. To better understand how heat affects health in Styria, and whether the early warning system works as intended, the Styrian Heat Protection Plan should be updated to accurately describe how warnings are issued, and to state how–and how often–it must be evaluated. Moreover, data should be collected and stored in a way that enables ongoing monitoring and regular evaluations.

• author: Grabner, Stephan Franz
• supervisor: Peter Månsson
• organization: Division of Risk Management and Societal Safety
• course: VBRM15 20251
• year: 2025
• type: H2 - Master's Degree (Two Years)
• subject: Technology and Engineering
• keywords: Heat, heatwave, adaptation, early warning system, heat protection plan, evaluation
• language: English
• id: 9202219
• date added to LUP: 2025-06-18 13:14:02
• date last changed: 2025-06-18 13:14:02