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Heat causes increase in occupational accidents

A study conducted by early career researchers from the Universities of Passau and Bern based on data from Switzerland has revealed: On days when temperatures exceed thirty degrees Celsius, the number of occupational accidents increases by 7.4 percent. With office workers, the night is the main cause.

Symbolic picture: Colourbox.

Large parts of the world are reeling under the current heatwave. Temperatures over 30 degrees Celsius have been recorded in the two German states Bavaria and Baden-Württemberg as well as in Switzerland, which has been particularly hard hit by global warming.

How do temperatures affect accidents at work? This is the question Katharina Drescher, an early career researcher at the University of Passau, and her co-author Benedikt Janzen from the University of Bern examined using data from Switzerland. In their study, the researchers assessed occupational accidents that had occurred in the period from 1996 to 2019. Switzerland lends itself well to such an investigation because temperatures vary significantly across the territory of this small country. Furthermore, administrative accident data is available for each single day and at a small-scale, regional level so that it can be matched to the weather conditions.

Everyone is equally affected by the heat in Switzerland

Katharina Drescher.

Katharina Drescher is a Ph.D. student at the Chair of Public Economics.

The study results are not altogether surprising: Drescher and Janzen demonstrate that the number of occupational accidents increases with temperatures over 30 degrees Celsius – by altogether 7.4 percent. What astounded the Passau economist, however, was the fact that – contrary to what studies from the US suggest – heat equally affected all employees in Switzerland: "We did not see any difference in our analysis in terms of sex, age, income or sector." In other words: Whether you work in construction or in an office – occupational accidents increased at the same rate in both groups.

Sleep deprivation identified as cause for accident increase among office workers

The causes, however, varied for the different groups: While hot nights cause everyone to sleep badly, daytime heat is what leads to more accidents among people who primarily work outdoors. With officer workers, temperatures in the nights before an accident occurs play a more significant role. To determine the relationship between temperatures, lack of sleep and rise in the number of occupational accidents, the researchers availed themselves not only of the accident data but also of the Swiss Health Survey.


The graphic shows the relation between accidents at work and the respective temperatures. Graphic: Katharina Drescher/Benedikt Janzen.

Drescher and her co-author also calculate the financial damage caused by the increased number of accidents on days with temperatures exceeding 30 degrees Celsius as well as on summer days with 25 to 30 degrees and on cold days with sub-zero temperatures: According to them, temperature-related accidents during the observation period incurred annual costs of roughly 90 million Swiss francs – with a strong upward trend. While there had been only one day in 1996 where temperatures rose to over 30 degrees Celsius, the number had increased to eleven by 2019.

Fellowship from the Austrian Economic Association

The study entitled "When Weather Wounds Workers: The Impact of Temperature on Workplace Accidents" appeared as a discussion paper for the "Bavarian Graduate Program in Economics". It is part of the cumulative doctoral thesis that Drescher is writing at the Chair of Public Economics of the University of Passau. For her doctoral research, the graduate from the Vienna University of Economics and Business was awarded a 4,000-euro fellowship from the Austrian Economic Association (NOeG). "I would like to congratulate Katharina Drescher on her remarkable achievement. With the study, she and Benedikt Janzen are helping to improve our understanding of the impact climate change has on the labour market and on health," says chairholder Professor Stefan Bauernschuster who is also Dean of the School of Business, Economics and Information Systems at the University of Passau.

Professor Stefan Bauernschuster

researches empirical evaluation of political measures

How do political measures influence decisions made by individuals and families?

How do political measures influence decisions made by individuals and families?

Professor Stefan Bauernschuster has held the Chair of Public Economics of the University of Passau since 2013. Moreover, he is a research professor at the ifo Institute in Munich, CESifo Affiliate and a member of the Social Policy Committee of the German Economic Association. He is also one of the principal investigators of the DFG Research Training Group 2720.

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