Simply put, climate change is caused by excessive production of greenhouse gases. As highlighted by the late Professor Tony McMichael, the “cause(s) of the causes” should not be overlooked.1 With climate change already close to an irreversible tipping point, urgent action is needed to reduce not only our mean (carbon) footprints but also the “number of feet”—that is, the growing population either already creating large footprints or aspiring to do so.

The mosquito Aedes (Ae). aegypti transmits the viruses that cause dengue, chikungunya, Zika and yellow fever. We investigate how choosing alternate emissions and/or socioeconomic pathways may modulate future human exposure to Ae. aegypti. Occurrence patterns for Ae. aegypti for 2061–2080 are mapped globally using empirically downscaled air temperature and precipitation projections from the Community Earth System Model, for the Representative Concentration Pathway (RCP) 4.5 and 8.5 scenarios.

The global human population now exceeds 7 billion and is projected to reach 10 billion around 2060. While population growth has been associated with certain benefits (e.g., economies of scale, technological advancements), theoretical models, probabilistic projections, and empirical evidence also indicate that this growth could increase the likelihood of many adverse events (e.g., climate change, resource shortages) and the impact of these events, as more people are exposed to the outcomes.

Global dimming refers to the decrease in surface solar radiation (SSR) observed from the 1960s to the 1980s at different measurement sites all around the world. It is under debate whether anthropogenic aerosols emitted from urban areas close to the measurement sites are mainly responsible for the dimming. In order to assess this urbanization impact on SSR, we use spatially explicit population density data of 0.08° resolution to construct population indices (PI) at 157 high data quality sites.