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A number of studies have shown that there is a time trend towards a reduction in the effects of heat on mortality. In the case of cold, however, there is practically no research of this type and so there is no clearly defined time trend of the impact of cold on mortality. Furthermore, no other specific studies have yet analysed the time trend of the impact of both thermal extremes by age group. We analysed data on daily mortality due to natural causes (ICD-10: A00-R99) in the city of Madrid across the period 2001–2009 and calculated the impact of extreme temperatures on mortality using Poisson regression models for specific age groups. The groups of age selected coinciding with the pre-existing age-groups analyzed in previous papers. For heat waves the groups of age used were: <10 years, 10–17 years, 18–44 years, 45–64 years, 65–74 years and over-75 years. For cold waves the groups of age used were: <1 year; 1–5 years, 6–17 years, 18–44 years, 45–64 years, 65–74 years and over-75 years. <1, 1–17, 18–44, 45–66, 65–74 and over-75 years. We controlled for confounding variables, such as air pollution, noise, influenza, pollen, pressure and relative humidity, trend of the series, as well as seasonalities and autoregressive components of the series. The results of these models were compared to those obtained for the same city during the period 1986–1997 and published in different studies. Our results show a lightly reduction in the effects of heat, especially in the over-45-year age group. In the case of cold, the behaviour pattern was the opposite, with an increase in its effect. Heat adaptation and socio-economic and public-health prevention and action measures may be behind this amelioration in the effects of heat, whereas the absence of such actions in respect of low temperatures may account for the increase in the effects of cold on mortality. From a public health point of view, the implementation of cold wave prevention plans covering all age groups is thus called for. [ABSTRACT FROM AUTHOR]

In recent years, a number of studies have been conducted with the aim of analysing the impact that high temperatures will have on mortality over different time horizons under different climate scenarios. Very few of these studies take into account the fact that the threshold temperature used to define a heat wave will vary over time, and there are practically none which calculate this threshold temperature for each geographical area on the assumption that there will be variations at a country level. To analyse the impact that high temperatures will have on mortality across the periods 2021–2050 and 2051–2100 under a high-emission climate scenario (RCP8.5), in a case: (a) where adaptation processes are not taken into account; and (b) where complete adaptation processes are taken into account. Based on heat-wave definition temperature (T threshold) values previously calculated for the reference period, 2000–2009, for each Spanish provincial capital, and their impact on daily mortality as measured by population attributable risk (PAR), the impact of high temperatures on mortality will be calculated for the above-mentioned future periods. Two hypotheses will be considered, namely: (a) that T threshold does not vary over time (scenario without adaptation to heat); and, (b) that T threshold does vary over time, with the percentile to which said T threshold corresponds being assumed to remain constant (complete adaptation to heat). The temperature data were sourced from projections generated by Coupled Model Intercomparison Project (CMIP5) climate models adapted to each region's local characteristics by the State Meteorological Agency (Agencia Estatal de Meteorología/AEMET). Population-growth projections were obtained from the National Statistics Institute (Instituto Nacional de Estadística/INE). In addition, an economic estimate of the resulting impact will be drawn up. The mean value of maximum daily temperatures will rise, in relation to those of the reference period (2000–2009), by 1.6⁰C across the period 2021–2050 and by 3.3⁰C across the period 2051–2100. In a case where there is no heat-adaptation process, overall annual mortality attributable to high temperatures in Spain would amount to 1414 deaths/year (95% CI: 1089–1771) in the period 2021–2050, rising to 12,896 deaths/year (95% CI: 9852–15,976) in the period 2051–2100. In a case where there is a heat-adaptation process, annual mortality would be 651 deaths/year (95% CI: 500–807) in the period 2021–2050, and 931 deaths per year (95% CI: 770–1081) in the period 2051–2100. These results display a high degree of heterogeneity. The savings between a situation that does envisage and one that does not envisage an adaptive process is €49,100 million/year over the 2051–2100 time horizon. A non-linear increase in maximum daily temperatures was observed, which varies widely from some regions to others, with an increase in mean values for Spain as a whole that is not linear over time. The high degree of heterogeneity found in heat-related mortality by region and the great differences observed on considering an adaptive versus a non-adaptive process render it necessary for adaptation plans to be implemented at a regional level. • In 2050–2100 the mean of the maximum temperatures in Spain will increase at a rate of 0.66 ºC / decade. • Without adaptation, the annual mortality by heat in 2050–2100 will be 12,900 deaths / year. • With complete adaptation the mortality attributable to heat would be 1400 deaths / year. • The economic cost of not adapting to full adaptation would amount to 49,100 million / year. [ABSTRACT FROM AUTHOR]

Global warming is resulting in an increase in temperatures which is set to become more marked by the end of the century and depends on the accelerating pace of greenhouse gas emissions into the atmosphere. Yet even in this scenario, so-called "cold waves" will continue to be generated and have an impact on health. This study sought to analyse the impact of cold waves on daily mortality at a provincial level in Spain over the 2021–2050 and 2051–2100 time horizons under RCP4.5 and RCP 8.5 emission scenarios, on the basis of two hypotheses: (1) that the cold-wave definition temperature (T threshold) would not vary over time; and, (2) that there would be a variation in T threshold. The results of a retrospective study undertaken for Spain as a whole across the period 2000–2009 enabled us to ascertain the cold-wave definition temperature at a provincial level and its impact on health, measured by reference to population attributable risk (PAR). The minimum daily temperatures projected for each provincial capital considering the above time horizons and emission scenarios were provided by the State Meteorological Agency. On the basis of the T threshold definition values and minimum daily temperatures projected for each province, we calculated the expected impact of low temperatures on mortality under the above two hypotheses. Keeping the PAR values constant, it was assumed that the mortality rate would vary in accordance with the available data. If T threshold remained constant over the above time horizons under both emission scenarios, there would be no cold-related mortality. If T threshold were assumed to vary over time, however, then cold-related mortality would not disappear: it would instead remain practically constant over time and give rise to an estimated overall figure of around 250 deaths per year, equivalent to close on a quarter of Spain's current annual cold-related mortality and entailing a cost of approximately €1000 million per year. Given that cold waves are not going to disappear and that their impact on mortality is far from negligible and is likely to remain so, public health prevention measures must be implemented to minimise these effects as far as possible. • If the coldwave definition temperature remain constant mortality associated not occur. • Mortality from cold-waves in the future will be reduced respect to 2000–2009 in Spain. • Important regional differences exist in Spain in relation to cold-waves impact. • Regional approach will be highly useful in implement regional cold prevention plans. [ABSTRACT FROM AUTHOR]