About this map

Mediterranean regions, like Southern California, receive most of their rainfall during mild winters. Much of the vegetation in the Los Angeles area is thus adapted to seasonal dry conditions. However, even native trees and shrubs can be negatively affected by prolonged periods of drought.

While temperatures in Southern California are projected to rise over the next few decades, precipitation is expected to decrease. The “Future Change” map above shows predicted declines in rainfall between the 1970-2000 baseline and 2061-2080. This prediction assumes a “regional rivalry” scenario: one in which fossil fuel dependence remains high, and international cooperation for climate change mitigation is heavily delayed (Shared Socioeconomic Pathway 3-7.0).

We’re still not entirely sure how precipitation will change in the future. The projected changes in this map are based on the Canadian Earth System Model version 5 (CanESM5), but different climate models produce slightly different predictions. It is important to incorporate this uncertainty into analyses of species richness and predictions of species distributions.

Data layers derived from: Fick and Hijmans 2017 in International Journal of Climatology, 37(12), 4302-4315.