Introduction

Direct health effects of extreme temperatures are a significant environmental health problem in Lithuania, and could worsen further under climate change. This paper attempts to describe the change in environmental temperature conditions that the urban population of Vilnius could experience under climate change, and the effects such change could have on excess heat-related and cold-related mortality in two future periods within the 21st century.

Methods

We modelled the urban climate of Vilnius for the summer and winter seasons during a sample period (2009–2015) and projected summertime and wintertime daily temperatures for two prospective periods, one in the near (2030–2045) and one in the far future (2085–2100), under the Representative Concentration Pathway (RCP) 8.5. We then analysed the historical relationship between temperature and mortality for the period 2009–2015, and estimated the projected mortality in the near future and far future periods under a changing climate and population, assuming alternatively no acclimatisation and acclimatisation to heat and cold based on a constant-percentile threshold temperature.

Results

During the sample period 2009–2015 in summertime we observed an increase in daily mortality from a maximum daily temperature of 30 °C (the 96th percentile of the series), with an average of around 7 deaths per year. Under a no acclimatisation scenario, annual average heat-related mortality would rise to 24 deaths/year (95% CI: 8.4–38.4) in the near future and to 46 deaths/year (95% CI: 16.4–74.4) in the far future. Under a heat acclimatisation scenario, mortality would not increase significantly in the near or in the far future. Regarding wintertime cold-related mortality in the sample period 2009–2015, we observed increased mortality on days on which the minimum daily temperature fell below − 12 °C (the 7th percentile of the series), with an average of around 10 deaths a year. Keeping the threshold temperature constant, annual average cold-related mortality would decrease markedly in the near future, to 5 deaths/year (95% CI: 0.8–7.9) and even more in the far future, down to 0.44 deaths/year (95% C: 0.1–0.8). Assuming a “middle ground” between the acclimatisation and non-acclimatisation scenarios, the decrease in cold-related mortality will not compensate the increase in heat-related mortality.

Conclusion

Thermal extremes, both heat and cold, constitute a serious public health threat in Vilnius, and in a changing climate the decrease in mortality attributable to cold will not compensate for the increase in mortality attributable to heat. Study results reinforce the notion that public health prevention against thermal extremes should be designed as a dynamic, adaptive process from the inception.

中文翻译：

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气候变化中与冷相关的死亡率与与热相关的死亡率：维尔纽斯（立陶宛）的案例研究

介绍

极端温度对健康的直接影响是立陶宛的一个重大环境健康问题，在气候变化下可能会进一步恶化。本文试图描述维尔纽斯城市人口在气候变化下可能经历的环境温度条件的变化，以及这种变化可能对 21 世纪未来两个时期与过热和过冷相关的死亡率产生的影响。

方法

我们在样本期间（2009-2015 年）模拟了维尔纽斯夏季和冬季的城市气候，并预测了两个预期时期的夏季和冬季每日气温，一个在近期（2030-2045 年），一个在遥远的未来（ 2085–2100)，在代表性浓度途径 (RCP) 8.5 下。然后，我们分析了 2009 年至 2015 年期间温度与死亡率之间的历史关系，并估计了在气候和人口变化下近期和远未来期间的预计死亡率，假设没有适应和适应热和冷，基于恒定百分比阈值温度。

结果

在 2009 年至 2015 年夏季的样本期间，我们观察到每日死亡率从最高每日温度 30°C（该系列的第 96 个百分位数）开始增加，平均每年约有 7 人死亡。在不适应环境的情况下，与热相关的年平均死亡率在不久的将来将上升至 24 人/年（95% CI：8.4-38.4），在远期将上升至 46 人/年（95% CI：16.4-74.4）未来。在热习服情景下，死亡率在近期或远期都不会显着增加。关于 2009-2015 年样本期间与冬季寒冷相关的死亡率，我们观察到日最低气温低于 - 12°C（该系列的第 7 个百分位）的日子死亡率增加，平均每年约有 10 人死亡. 保持阈值温度恒定，与感冒相关的年平均死亡率在不久的将来会显着下降，降至 5 人/年（95% CI：0.8-7.9），在很远的将来甚至会更多，降至 0.44 人/年（95% C：0.1-0.8） ）。假设在适应环境和非适应环境之间有一个“中间地带”，与寒冷相关的死亡率的下降不会补偿与高温相关的死亡率的增加。

结论

极端高温，包括高温和低温，对维尔纽斯的公共健康构成严重威胁，在气候变化中，低温导致的死亡率下降无法弥补高温导致的死亡率增加。研究结果强化了这样一种观念，即从一开始就应该将针对极端高温的公共卫生预防设计为一个动态的、适应性的过程。