Projections of excess deaths related to cold spells under climate and population change scenarios: A nationwide time series modeling study

Abstract

Background: Future climate change is likely to alter cold spell-related disease burden. Few projection studies have considered the potential impact of the aging population with changing population size on cold spell-related disease burdens.

Methods: We derived the association between cold spells and daily mortality for 272 main cities in mainland China. We combined these associations with modeled daily temperatures from three different climate models under two climate change scenarios and three population scenarios to project excess deaths related to cold spells. Furthermore, we used the factor separation method to calculate the independent contribution of future population size, age structure, and climate change on projected deaths attributable to cold spells.

Findings: Compared to the baseline period, future excess deaths related to cold spells are expected to increase over most of the decades under RCP 2.6 (81.5% in 2050 s and 37% in 2090 s) and RCP 4.5 (55.5% in 2050 s and -19% in 2090 s). The factor analysis indicated that the rise of the aged population (≥65) substantially would amplify the excess deaths related to cold spells (increase by 101.1% in the 2050 s and 146.2% in the 2090 s). For the near future (2021-2040), population aging could fully offset the influence of decreased cold-spell days. In the middle of this century (2051-2070), the total excess deaths will exhibit significant variation across three scenarios. By the end of 21 century (2081-2100), the population shrinking would reduce the total excess deaths.

Interpretation: Excess deaths related to cold spells may still increase in a warming climate and future demographic shifts would produce considerable influences in this increase for different periods.

Keywords: Aging; China; Climate Change; Cold Spell.