Abstract
Mountains play a vital role in shaping regional and global climate,
altering atmospheric circulation and precipitation patterns. To this
end, identifying projected changes in mountain precipitation is
significantly challenging due to topographic complexity. This study
explains how mountain precipitation could respond to rising greenhouse
gases. Using a series of century-long fully coupled high-resolution
simulations conducted with the Community Earth System Model, we aim to
disentangle future changes in mountain precipitation in response to
atmospheric carbon dioxide (CO2) perturbations. We identify five
low-latitude mountain ranges with elevation-dependent precipitation
response, including New Guinea, East Africa, Eastern Himalayas, Central
America, and Central Andes. Those mountains are expected to have a
mixture of increasing and decreasing precipitation in response to
CO2-induced warming, especially over the summit and steep topography. To
elucidate the mechanisms controlling future changes in mountain
precipitation, we propose ‘orographic moist-convection feedback’ in
which an increase in low-level relative humidity enhances local
precipitation by strengthening the upward motion through moist processes
for the wetting response and vice versa for the drying response. The
effects of Mountain precipitation changes can be extended to hydrology
and could lead to significant consequences for human societies and
ecosystems.