Climate-driven disturbances amplify forest drought sensitivity

Nature Portfolio (Springer Nature) | June 7th, 2024

Climate-informed hydrologic modeling and policy typology to guide managed aquifer recharge

American Association for the Advancement of Science (AAAS) | April 21st, 2021

Harvesting floodwaters to recharge depleted groundwater aquifers can simultaneously reduce flood and drought risks and enhance groundwater sustainability. However, deploy

Harvesting floodwaters to recharge depleted groundwater aquifers can simultaneously reduce flood and drought risks and enhance groundwater sustainability. However, deployment of this multibeneficial adaptation option is fundamentally constrained by how much water is available for recharge (WAFR) at present and under future climate change. Here, we develop a climate-informed and policy-relevant framework to quantify WAFR, its uncertainty, and associated policy actions. Despite robust and widespread increases in future projected WAFR in our case study of California (for 56/80% of subbasins in 2070–2099 under RCP4.5/RCP8.5), strong nonlinear interactions between diversion infrastructure and policy uncertainties constrain how much WAFR can be captured. To tap future elevated recharge potential through infrastructure expansion under deep uncertainties, we outline a novel robustness-based policy typology to identify priority areas of investment needs. Our WAFR analysis can inform effective investment decisions to adapt to future climate-fueled drought and flood risk over depleted aquifers, in California and beyond.

Climate, Drought, and Sea Level Rise Scenarios for the Fourth California Climate Assessment

California Energy Commission (CEC) | August 27th, 2018

Daily temperature and precipitation over California at a resolution of 1/16° (about 6 km, or 3.7 miles) were generated to support climate change impact studies for the

Daily temperature and precipitation over California at a resolution of 1/16° (about 6 km, or 3.7 miles) were generated to support climate change impact studies for the energy system and other sectors featured in the California’s Fourth Climate Change Assessment. The data, derived from 32 coarse-resolution (~ 100 km) global climate models (GCMs), were bias corrected and downscaled using the Localized Constructed Analogues (LOCA) statistical method. The data cover 1950-2005 for the historical period and 2006-2100 for two future climate projections using medium and high greenhouse gas and aerosol emissions scenarios. Statewide, temperature is projected to increase 2-4 °C (medium emissions scenario) to 4-7 °C (high emissions scenario) by the end of this century. Precipitation shows fewer wet days, wetter winters, drier springs and autumns, and an increase in dry years as well as maximum precipitation in a single day. Ten GCMs that closely simulate California’s climate are identified for studies where all 32 GCMs cannot be used. Additional variables were downscaled for these 10, including wind speed, specific and relative humidity, and surface solar radiation. Four models that span the temperature and precipitation changes from the 10 are identified for studies that cannot accommodate the 10. Wind speed shows small decreases, while relative humidity changes are more complicated, with coastal increases but decreases inland. Surface solar radiation shows small Southern California increases in spring. The downscaled fields were applied to the Variable Infiltration Capacity (VIC) land surface model to develop snow cover, soil moisture, runoff, water loss from plants, surface heat fluxes, and other parameters. Moisture deficit is projected to increase over much of the state, particularly Northern California and the Sierra Nevada, while top level soil moisture is projected to decrease, particularly in Southern California. Most streamflows shift to earlier in the year, with the bigger shifts experienced in basins which currently have substantial contributions from snowmelt. Two versions of a 20-year dry spell were identified from one of the GCM simulations to investigate future drought: the original episode from 2051-2070, and one shifted earlier in the century with temperatures consistent with 2023-2042. For both, we provide downscaled temperatures and precipitation along with VIC hydrological output. Sea level rise (SLR) projections for California were generated using a probabilistic approach employing estimates of the components that contribute to global and regional SLR, including new science on the possibility of increased contribution from Antarctica. Hourly projections of sea level at selected coastal locations were generated out to 2100 that include tides, regional and local weather influences, and short period Pacific climate fluctuations along with the aforementioned sea level rise scenarios. The climate scenario and SLR data are available online from cal-adapt.org.

Climatic backdrop for Pueblo cultural development in the southwestern United States

Nature Portfolio (Springer Nature) | May 24th, 2022

While climatic triggers for collapse and population migrations of ancestral Pueblo communities have been proposed, little is known about the overall climatic backdrop for

While climatic triggers for collapse and population migrations of ancestral Pueblo communities have been proposed, little is known about the overall climatic backdrop for the entire pre-Hispanic Pueblo period (ca. 1300 to 460 B2K). Here, we report data from stalagmite HC-1, from Hidden Cave, Guadalupe Mountains, New Mexico, covering the past 3400 years, showing an interval of increased frequency of droughts from 1260 to 370 yr B2K that is coeval with the entire pre-Hispanic Pueblo period. Our record suggests that this puebloan Late Holocene climatic interval was the most arid and highly variable climatic period of the last 3400 years. Climatic conditions favoring the introduction of cultivation existed prior to the Pueblo period during more pluvial-like conditions from at least 3400 to 1260 yr B2K. Hence, the change from the Desert Archaic/Basketmaker to Pueblo cultures was associated with a quick transition to increasing aridity into and through the Pueblo period associated with greater urbanization and the establishment of pueblo population centers.

Climatic Fluctuations, Drought, and Flow in the Colorado River Basin

U.S. Geological Survey (USGS) | August 16th, 2004

Climatic regulation of the neurotoxin domoic acid

National Academy of Sciences (NAS) | January 9th, 2017

Domoic acid is a potent neurotoxin produced by certain marine microalgae that can accumulate in the foodweb, posing a health threat to human seafood consumers a

Domoic acid is a potent neurotoxin produced by certain marine microalgae that can accumulate in the foodweb, posing a health threat to human seafood consumers and wildlife in coastal regions worldwide. Evidence of climatic regulation of domoic acid in shellfish over the past 20 y in the Northern California Current regime is shown. The timing of elevated domoic acid is strongly related to warm phases of the Pacific Decadal Oscillation and the Oceanic Niño Index, an indicator of El Niño events. Ocean conditions in the northeast Pacific that are associated with warm phases of these indices, including changes in prevailing currents and advection of anomalously warm water masses onto the continental shelf, are hypothesized to contribute to increases in this toxin. We present an applied domoic acid risk assessment model for the US West Coast based on combined climatic and local variables. Evidence of regional- to basin-scale controls on domoic acid has not previously been presented. Our findings have implications in coastal zones worldwide that are affected by this toxin and are particularly relevant given the increased frequency of anomalously warm ocean conditions.

Climatology and changes in internal intensity distributions of global precipitation systems over 2001-2020 based on IMERG

Journal of Hydrology (Elsevier) | March 11th, 2023

The internal intensity distributions of precipitation systems are closely related to precipitation dynamics. Understanding its climatology and changing characteristics is

The internal intensity distributions of precipitation systems are closely related to precipitation dynamics. Understanding its climatology and changing characteristics is important for comprehending climate change, enhancing atmospheric model, and obtaining accurate hydrologic responses. However, due to the various limitations of precipitation observations, the internal intensity distributions of global precipitation systems have not been thoroughly investigated. This study uses the Integrated Multi-satellitE Retrievals for Global Precipitation Measurement (IMERG) data during 2001-2020 to investigate the internal intensity distributions of global precipitation systems, by analyzing the climatology and changes in the radial intensity distributions and the core-region intensity of precipitation systems. The results indicate that precipitation systems with larger spatial sizes tend to have higher intensity. Small- and medium-size precipitation systems exhibit the most obvious changes in the inner regions of precipitation systems, with higher intensity during 2001-2010 than 2011-2020. The large-size precipitation systems have slightly higher intensity at each radius of the systems during 2011-2020. Upon further investigation of the core-region intensity of precipitation systems, the small- and medium-size precipitation systems both exhibit significant decreases during 2001-2020 with trends at -1.13 and -2 mm/h per century, respectively. The large-size precipitation systems exhibit nonsignificant increasing trends during 2001-2020. The results also show regional differences, with decreased core-region intensity over most tropical regions and increased core-region intensity over most subtropical regions. This study provides an alternative perspective on the climatology and changing features of precipitation from the system view, and the results revealed could have significant implications on global climate change.

Coastal flooding - potential projections: 2000–2100

California Energy Commission (CEC) | July 31st, 2012

The change in flooding potential along the California coast over the twenty?first century was estimated from both ocean wave and sea level rise projections produced from

The change in flooding potential along the California coast over the twenty?first century was estimated from both ocean wave and sea level rise projections produced from global climate model data. Changes in flooding potential were inferred from changes in wave runup (the vertical height reached by wave?driven water levels), which depends on the instantaneous sea level (or still water level), beach slope, and wave height and wave period. The still water level is the superposition of regional (or relative) mean sea level, the tide, and non?tide sea level fluctuations. Non?tide sea level fluctuations include both the steric response associated with El Niño–related variability that can persist up to a year or more, and local storm–forced variability (storm surge). The potential for greatest coastal flooding occurs when extremes in waves and still water level occur nearly simultaneously. Wave activity provides the primary driving force for coastal flooding. Wave model significant wave height (Hs) and non?tide sea level projections were generated for a seven global climate model simulations. Comparison of the Hs and nontide projections with wave model hindcast Hs and observed non?tide fluctuations suggest that the characteristics and incidence of extreme Hs and non?tide fluctuations will not increase appreciably over the twenty?first century. Thus, because astronomical tide?forcing will not increase, increases in relative mean sea level will largely determine the potential for increased ocean?driven flooding along the California coast. If relative mean sea level along the California coast reaches global mean sea level rise projections associated with climate change, extreme flooding events expected to occur once in about 100 years under stationary relative mean sea levels will occur annually.

Coastal hardening and what it means for the world’s sandy beaches

Publisher not available | December 5th, 2024

Coastal vulnerability across the Pacific dominated by El Niño/Southern Oscillation

Nature Portfolio (Springer Nature) | September 21st, 2015

To predict future coastal hazards, it is important to quantify any links between climate drivers and spatial patterns of coastal change. However, most studies of future c

To predict future coastal hazards, it is important to quantify any links between climate drivers and spatial patterns of coastal change. However, most studies of future coastal vulnerability do not account for the dynamic components of coastal water levels during storms, notably wave-driven processes, storm surges and seasonal water level anomalies, although these components can add metres to water levels during extreme events. Here we synthesize multi-decadal, co-located data assimilated between 1979 and 2012 that describe wave climate, local water levels and coastal change for 48 beaches throughout the Pacific Ocean basin. We find that observed coastal erosion across the Pacific varies most closely with El Niño/Southern Oscillation, with a smaller influence from the Southern Annular Mode and the Pacific North American pattern. In the northern and southern Pacific Ocean, regional wave and water level anomalies are significantly correlated to a suite of climate indices, particularly during boreal winter; conditions in the northeast Pacific Ocean are often opposite to those in the western and southern Pacific. We conclude that, if projections for an increasing frequency of extreme El Niño and La Niña events over the twenty-first century are confirmed, then populated regions on opposite sides of the Pacific Ocean basin could be alternately exposed to extreme coastal erosion and flooding, independent of sea-level rise.