Dissertation

Climate change and population dynamics: estimating the implications for health and mortality

Abstract

This thesis examines how climate change affects demographic processes and health outcomes across different populations and life stages. It integrates environmental and demographic perspectives through three interconnected studies that explore the multifaceted links between climate variability, population dynamics, and human well-being. The first study synthesizes existing evidence on climate change and population dynamics in the Global South, highlighting how environmental stressors influence fertility, mortality, and migration patterns. It reviews the evidence and sketches out the mechanisms through which climate change influence population dynamics and pinpoints the unequal burden borne by low-income populations and the need to integrate climate considerations into demographic research and policy.
The second study empirically investigates temperature-related mortality among older adults in Italy, focusing on the harvesting effect the short-term mortality displacement following extreme temperature events. Using province-level mortality data combined with high-resolution temperature, and other meteorological indicators, Poisson regression models reveal that both extreme cold and heat substantially increase mortality risks in Italy. The findings indicate that high winter mortality reduces vulnerability to heat in subsequent summers. However, extremely hot days still lead to significant increases in deaths, showing stronger public health measures are needed to help people adapt. 
The third study empirically analyses the impact of thermal stress on child health outcomes in India by linking climate reanalysis data with Demographic and Health Survey data. Logistic regression models show that higher thermal exposure increases the risk of wasting and underweight among children under five, particularly among socioeconomically disadvantaged households. The analysis identifies significant heterogeneity by sex, residence, maternal education, and access to electricity. 
Collectively, these studies demonstrate that climate change operates as an independent driver reshaping population dynamics and health outcomes. The thesis advances demographic theory by including climate factors into population modelling and highlights the urgent need for integrated policies to protect vulnerable groups and ensure sustainable demographic futures in the changing climate.