Heat waves and elderly mortality from respiratory and cardiovascular diseases in Brazilian state capitals: An analysis of the present (196-2016) and projections for the near future (2030-2050) and distant future (2079-2099) in different climate change scenarios

Author(s)

Fernanda Rodrigues Diniz

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto Astronômico e Geofísico (IAG/SBD)
• Defense date: 2022-05-31

Examining board members

Fabio Luiz Teixeira Goncalves; Wilson Jacob Filho; Anderson Spohr Nedel; Rosmeri Porfirio da Rocha; Maria Elisa Siqueira Silva

• Advisor: Fabio Luiz Teixeira Goncalves

Abstract

Heat waves are becoming more frequent and more intense all over the world, including in Brazil. The literature points out that due to climate change, extreme heat episodes should be even more frequent in the future. The elderly are more vulnerable to extreme heat due to their dysfunctional thermoregulatory mechanisms, in addition they are more prone to diseases involving the systems that regulate body temperature, such as respiratory (RSPD) and cardiovascular (CVD) diseases. In this context, this thesis aimed to quantify the mortality of elderly people from RSPD and CVD related to heat waves during hot and cold periods in the capitals of the 26 Brazilian states and in the Federal District. The analyzes were carried out in the period of the present (1996 to 2016), near future (2030 to 2050) and distant future (2079 to 2099). For the projections, two climate change scenarios (RCP4.5 and RCP8.5) and two regionalized climate models (Eta-HADGEM2-ES and Eta-MIROC5) were considered. Another important aspect in future projections was the quantification of mortality for the hypotheses of adaptation and non-adaptation to the future climate. Heat waves were identified in Brazilian capitals both in the present and in the future using the definition that a heat wave is a period of at least three consecutive days with maximum daily temperatures above the daily thresholds of the 90th, 95th and 98th percentiles of the maximum temperature of the climatological reference period. In addition to being identified, heat waves were characterized as to their frequency, duration and intensity. Using Generalized Linear Models (GLM), the impacts of heat waves on the mortality of elderly people from CVD and RSPD were quantified in all the country\'s capitals, initially in terms of relative risk (RR) and later in mortality rate. In order to obtain a summary measure of the impacts of heat waves on mortality among the elderly in Brazil and its regions, meta-analytic processes were applied to the results obtained for Brazilian capitals. The results showed that the climate models have convergent results, however, the Eta-HADGEM2-ES model showed more pessimistic projections for the future compared to the Eta-MIROC5 model. As well, the projections in the RCP8.5 scenario were more pessimistic, especially in the distant future (2079-2099). The projections showed that the maximum temperature in Brazil is expected to increase by up to 5.8°C and the relative humidity will decrease by up to -11% in the future, consequently the projections showed that heat waves in Brazilian capitals will be more frequent, more intense and more persistent in both hot and cold periods. The results showed that due to the increase in heat waves in the future, the risk of mortality associated with heat waves is also expected to increase, especially for more intense heat waves (P98). On average in Brazil, the risk of elderly mortality from CVD is expected to increase by up to 1257% compared to the present and by DRSP by up to 1433% in the worst-case scenario. The results showed that if there is no adaptation, it is expected that the heatwave-related elderly mortality in Brazil will increase, especially in 2079-2099 in the RCP8.5 scenario (an average of 974 annual deaths per 100,000 elderly inhabitants due to CVD and 20 annual deaths per 100,000 elderly people due to RSPD). Mortality related to heat waves is expected to increase much more in the North, Midwest and Southeast regions of the country, mainly due to CVD. On the other hand, under a hypothetical adaptation assumption, it is expected that the death rate related to heat waves will still increase, but the increase will be much smaller than under the hypothesis of no adaptation (on average 80 annual deaths from CVD per 100,000 elderly inhabitants and 1.7 annual deaths from RSPD per 100,000 elderly inhabitants). Therefore, adaptation to heat waves is extremely important to reduce the number of elderly deaths from CVD and RSPD in Brazil in the future. However, the Urban Adaptation Index (UAI) showed that no Brazilian capital currently has an adaptive potential considered ideal, requiring attention from public policies, mainly in the dimensions of housing, environmental management and responses to climate impacts so that the adaptive potential of Brazilian capitals increases, thus being able to avoid the increase in the mortality of the elderly population in the coming years. (AU)

• FAPESP's process: 19/09879-1 - Elderly mortality related to heat waves in the capitals of Brazil: an analysis in the present and future projections in the climate change scenarios
• Grantee: Fernanda Rodrigues Diniz
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)