This study is possibly the first to investigate the impact of carbon dioxide (CO2) emissions on life expectancy for 68 low- and middle-income countries for the 1990–2017 period. The analysis was carried out on a disaggregated basis on two dimensions: (1) the sources of CO2 emissions (i.e., consumption-based or production-based CO2 emissions) and (2) the level of economic development (i.e., developing or emerging) of countries. The results support the evidence of a negative association between life expectancy and CO2 emissions for the whole sample as well as for the group of emerging countries. This finding occurred irrespective of whether the CO2 emissions were consumption-based or production-based, suggesting that both consumption and production may reduce the life expectancy of the people in these groups of economies through the generation of harmful pollutants. In contrast, CO2 emissions, regardless of their sources, seem to improve the life expectancy of those in the group of developing countries in our study sample. In this regard, developing countries seem to be effectively importing emissions. Our findings suggest that the favorable impact of CO2 emissions on life expectancy is attributable to consumption rather than production. Furthermore, income growth alone cannot provide a solution for environmental degradation nor ensure a healthier life for the population.