Projections of Cause-Specific Mortality and Demographic Changes under Climate Change in the Lisbon Metropolitan Area: A Modelling Framework

Abstract

Climate change and related events, such as rising temperatures and extreme weather, threaten population health and well-being. This study quantified the impact of climate change on temperature-related, cause-specific mortality while considering adaptations and future demographic changes in Lisbon Metropolitan Area, Portugal. A distributed lag non-linear model (DLNM) was applied to quantify the burden of temperature-related mortality during the present (or reference, 1986–2005) scenario and a future scenario (2046–2065). There was an increase of 0.33% in temperature-related excess mortality (95% CI: 0.02 to 0.59) and significantly lower all-cause deaths in the future. These measurements were attributable to extreme cold and considered an adaptation threshold of 1 °C with no population changes, resulting in an estimated net difference of −0.15% (95% CI: −0.26 to −0.02), a threshold of 1 °C with a high population scenario of −0.15% (95% CI: −0.26 to −0.01), and a threshold of 1 °C with a low population scenario of −0.15% (95% CI: −0.26 to −0.01). Moderate cold exposure under a threshold of 1 °C and a high population scenario reduced future temperature-related deaths and diabetes mellitus (−1.32, 95% CI: −2.65 to 0.23). Similarly, moderate heat exposure under a threshold of 4 °C and a high population scenario had the highest increase in net changes (6.75, 95% CI: −5.06 to 15.32). The net difference in AF% was due to ischemic heart disease, which was the highest for moderate heat exposure with an adaptation threshold of 4 °C only. It decreased slightly with increasing adaptation levels. The most significant increase in net differences for temperature-related excess deaths occurred in respiratory diseases and was associated with heat. A significant decline in net differences was also observed in excess cold-related deaths due to respiratory disease. These findings contribute to the discussion of how climate change impacts human health. Furthermore, they can help guide and monitor adaptation policies in response to climate change.