Climate change is expected to decrease mean precipitation in California, but changes in hydroclimate extremes are likely to have more immediate and significant impacts on California water resources, ecosystems, and economy. Paleoclimate records can provide valuable baseline data for constraining natural hydroclimate variability and improving climate projections, but quantitative precipitation records are limited. A new study by de Wet et al. (2021) provides the first semi‐quantitative record of early Holocene precipitation in central California, based on speleothem calcium isotope (δ44Ca) variations, that indicates that precipitation variability during and preceding the 8.2 kyr event approached or exceeded that of recent decades. This study outlines a new approach for developing more robust and quantitative hydroclimate records, and also highlights that precipitation “whiplash” is a ubiquitous feature of California's climate that we must prepare for, especially given the likelihood that human‐caused climate change is already increasing the frequency and severity of hydrologic extremes.
Recently, year‐to‐year swings in California winter precipitation extremes have resulted in drought, wildfires, and floods causing billions of dollars in damage. These recent precipitation swings represent an increasing trend in variability of California's hydroclimate over the past decades. Here, we put this trend in a longer‐term context using tree‐ring‐based precipitation, streamflow, and snow water equivalent reconstructions. We show that the statewide rise in hydroclimate variability in the 20th century is driven by an increasing trend in the magnitude of wet extremes. A prior period of strong variability in the 16th century, in contrast, is related to an increasing trend in the magnitude of dry extremes. Our results are consistent with climate model simulations that suggest an increasingly volatile future for California's hydroclimate and highlight the importance of collaboration between scientists and water resource managers to incorporate this increased variability into their decision‐making and planning, acknowledging higher risks for compound events.
more » « less- NSF-PAR ID:
- 10443817
- Publisher / Repository:
- DOI PREFIX: 10.1029
- Date Published:
- Journal Name:
- Geophysical Research Letters
- Volume:
- 49
- Issue:
- 19
- ISSN:
- 0094-8276
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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