Predicted changes to the rate of human decomposition due to climate change during the 21st century

Estimating the post mortem interval is an important aspect of the work of forensic pathologists and forensic anthropologists. Whilst temperature is generally agreed as the most important variable affecting decomposition, some formulae also incorporate relative humidity for a more detailed estimate. Both these variables are impacted by anthropogenic climate change. This study aims to provide a first overview of the likely extent to which anthropogenic climate change will affect future rates of decomposition. The post mortem interval from death until skeletonization (PMIDS) was calculated using the formula by Vass [1], as well as temperature and humidity predictions from two different climate models, to predict changes in the speed of decomposition between the decades 2020–2029 and 2090–2099. The changes are calculated for different climate zones, and a global average, as well as different climate change scenarios, and for decomposition starting in January and July. The estimated PMIDS is significantly (p < 0.05) decreased in most scenarios, with the largest global decrease of 33.5% in the SSP5–8.5 scenario, with decomposition starting in July, and the smallest decrease of 2.6% in the SSP1–2.6 scenario, with decomposition starting in January. The significantly accelerated decomposition in the SSP5- 8.5 scenario will increase the workload of forensic anthropologists, by decreasing the time until skeletonization, after which the expertise of a forensic anthropologist is more likely to be needed. However, climate change is also predicted to decrease the accuracy of the formulae used for PMI estimation, even in regions where levels of precision are currently good. The present authors therefore argue, that the impacts of climate change will warrant increasing attention in the field of forensic anthropology, and that more research into PMI estimation will be needed particularly in warmer and drier regions.