Human populations in the world’s mountains: Spatio-temporal patterns and potential controls

Abstract

Changing climate and human demographics in the world’s mountains will have increasingly profound environmental and societal consequences across all elevations. Quantifying current human populations in and near mountains is crucial to ensure that any interventions in these complex social-ecological systems are appropriately resourced, and that valuable ecosystems are effectively protected. However, comprehensive and reproducible analyses on this subject are lacking. Here, we develop and implement an open workflow to quantify the sensitivity of mountain population estimates over recent decades, both globally and for several sets of relevant reporting regions, to alternative input dataset combinations. Relationships between mean population density and several potential environmental covariates are also explored across elevational bands within individual mountain regions (i.e. “sub-mountain range scale”). Globally, mountain population estimates vary greatly—from 0.344 billion (<5% of the corresponding global total) to 2.289 billion (>31%) in 2015. A more detailed analysis using one of the population datasets (GHS-POP) revealed that in ∼35% of mountain sub-regions, population increased at least twofold over the 40-year period 1975–2015. The urban proportion of the total mountain population in 2015 ranged from 6% to 39%, depending on the combination of population and urban extent datasets used. At sub-mountain range scale, population density was found to be more strongly associated with climatic than with topographic and protected-area variables, and these relationships appear to have strengthened slightly over time. Such insights may contribute to improved predictions of future mountain population distributions under scenarios of future climatic and demographic change. Overall, our work emphasizes that irrespective of data choices, substantial human populations are likely to be directly affected by—and themselves affect—mountainous environmental and ecological change. It thereby further underlines the urgency with which the multitudinous challenges concerning the interactions between mountain climate and human societies under change must be tackled.

A comprehensive and version-controlled database of glacial lake outburst floods in High Mountain Asia

“…6). Coupling of GLOF paths with distributed population data (Thornton et al, 2022) would allow for the computation of people potentially impacted, coupled with remotely sensed vegetation and agriculture data, which would allow for estimates of local economic and ecological impacts. GLOF paths could also be used to develop hazard zonation maps, as is already standard practice for avalanches in many regions.…”

Evaluating ecosystem protection and fragmentation of the world's major mountain regions

“…High levels of biodiversity can be attributed to various geology, hydrology, and elevations that provide a diversity of habitats and ecosystem services (Chester et al, 2013;Jacobs et al, 2021;Rahbek et al, 2019). Although mountains are considered to have lower levels of human development than other landscapes (Weber, 2004), they are nevertheless home to 1−2 billion people (Körner et al, 2017;Thornton et al, 2022) and provide freshwater to billions more (Viviroli et al, 2020). Mountains are not disproportionately protected globally; nearly 40% lack any form of protection and fall short of internationally recognized protection targets (Elsen et al, 2018).…”

The exposure of the world’s mountains to global change drivers

“… 12 , 13 Covering less than 20% of the earth’s surface, mountains are extraordinarily important for both humans and biodiversity. 14 From a human and demographic perspective, mountains host between 10% and 20% of world’s population, depending on the mountain definition applied, 14 , 15 and they provide both mountain and lowland communities with essential ecosystem services. 16 , 17 , 18 From a biodiversity perspective, mountains sustain approximately one-third of the diversity of terrestrial species 19 and are home to half of the 34 globally recognized biodiversity hotspots.…”