It is not a gainsaying that challenges to both healthy living and the environment are the result of deteriorating environmental quality with the attendant effect on environmental sustainability. To provide a solution to the issue, our study uses long time-series data from 1960 to 2018, and employs an overlapping generational model, the Bayer–Hanck cointegration test, wavelet coherence, Fourier Toda–Yamamoto, and Breitung–Candelon frequency-domain spectral causality tests to investigate the causal relationships among carbon emissions (CO2), economic growth (GDP), and life expectancy (LE) in Turkey. Different from the literature, we find a positive co-movement between life expectancy and CO2 and a positive correlation between LE and GDP at different scales; CO2 has a causal relationship with LE and a bidirectional causal relationship between LE and GDP, as well as short, medium, and long-run causal relationships with LE; GDP has medium and long-run causal relationships with LE, and LE has short, medium, and long-run causal relationships with GDP. Our findings guide policymakers on their policy decision-making that will address the energy consumption, environmental degradation, human health, environmental hazards, and allocation to science and technology in Turkey with the aim of ensuring overall sustainable development.