Heat‑related mortality amplified during the COVID‑19 pandemic in 2020.
Excess mortality not directly related to the virus has been shown to have increased during the COVID-19 pandemic, including heat-related mortality. Extreme temperatures, and in particular heatwaves, are well known for dramatic peaks in mortality (e.g. 1981, 2003, 2013, 2018), and a major factor of concern regarding public health impacts of climate change. However, during 2020 this link was aggravated when compared to previous heatwaves. Several warm periods have observed during that year in
Portugal, including the warmest July since 1931. Using meteorological data from the ERA5 reanalysis and crossing with mortality and hospital admission data, the link between warm/cold spells and mortality has been evaluated and modeled, comparing the pandemic and pre-pandemic periods. The analysis shows that a significant reduction in search for medical care - due to fear of the population and/or reduced health care availability - resulted in an amplification of at least 50% in heat-related deaths (a total around 1500 deaths due to heat exposure), when compared to what would have been expected for similar meteorological conditions in a normal pre-pandemic period.
This study was led by Pedro M. Sousa (IPMA) in collaboration with researchers from Instituto Dom Luiz (Ricardo M. Trigo, Ana Russo and João L. Geirinhas) and from Instituto Ricardo Jorge (Ana Rodrigues, Susana Silva e Ana Torres), and published in International Journal of Biometeorology.
Figure caption: a) Mortality versus temperature anomalies. Red/blue bars represent positive/negative temperature anomalies. Lines depict the relative anomaly in mortality, considering all deaths (solid black line), COVID-19 deaths (dashed black line), and all causes except COVID-19 (brown line). b) Absolute values for the daily mean temperatures (thin black line and colored shaded areas), maximum temperatures (red line), and minimum temperatures (blue line) in continental Portugal during 2020.