reference : How has human-induced climate change affected California drought risk?

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/report/nca4/chapter/southwest/reference/4fbaaa13-99d2-43df-93db-2be546f18892
Bibliographic fields
reftype Journal Article
Abstract The current California drought has cast a heavy burden on statewide agriculture and water resources, further exacerbated by concurrent extreme high temperatures. Furthermore, industrial-era global radiative forcing brings into question the role of long-term climate change with regard to California drought. How has human-induced climate change affected California drought risk? Here, observations and model experimentation are applied to characterize this drought employing metrics that synthesize drought duration, cumulative precipitation deficit, and soil moisture depletion. The model simulations show that increases in radiative forcing since the late nineteenth century induce both increased annual precipitation and increased surface temperature over California, consistent with prior model studies and with observed long-term change. As a result, there is no material difference in the frequency of droughts defined using bivariate indicators of precipitation and near-surface (10 cm) soil moisture, because shallow soil moisture responds most sensitively to increased evaporation driven by warming, which compensates the increase in the precipitation. However, when using soil moisture within a deep root zone layer (1 m) as covariate, droughts become less frequent because deep soil moisture responds most sensitively to increased precipitation. The results illustrate the different land surface responses to anthropogenic forcing that are relevant for near-surface moisture exchange and for root zone moisture availability. The latter is especially relevant for agricultural impacts as the deep layer dictates moisture availability for plants, trees, and many crops. The results thus indicate that the net effect of climate change has made agricultural drought less likely and that the current severe impacts of drought on California’s agriculture have not been substantially caused by long-term climate changes.
Author Linyin Cheng; Martin Hoerling; Amir AghaKouchak; Ben Livneh; Xiao-Wei Quan; Jon Eischeid
DOI 10.1175/JCLI-D-15-0260.1
Issue 1
Journal Journal of Climate
Keywords Physical Meteorology and Climatology,Climate change,Models and modeling,Climate models,Regional models
Pages 111-120
Title How has human-induced climate change affected California drought risk?
Volume 29
Year 2016
Bibliographic identifiers
.reference_type 0
_record_number 19542
_uuid 4fbaaa13-99d2-43df-93db-2be546f18892