Tropical montane cloud forests (TMCFs) in the Andes, with mild temperatures and plenty of water, boast prodigious biocultural diversity. Runoff from these slopes supports local communities by supplying drinking water and irrigation to growing lowland cities. However, precipitation in the region is sensitive to human environmental impacts and effective conservation planning requires assessing past and future climate changes in local cultural, historical, and political contexts. In particular, Earth System Models (ESMs) suggest a reduction in precipitation over most tropical land, including TMCFs in the Andes during the twentieth century, has been driven largely by increases in aerosol emissions (Wang, 2015). With the exception of the Amazon rainforest, this trend reverses in the twenty first century, with increases in precipitation over Asia, Central Africa, and the tropical Andes, as greenhouse gas-driven changes become the dominant response (Stocker et al., 2013; Kooperman et al., 2018a). Although multi-model mean changes are large, many ESMs show opposing trends on regional scales, and historical observations are limited, leading to uncertainties for past and future changes.