A 9200-year-long Holocene record of pollen, magnetic susceptibility (MS), and sedimentation rates from Pup Lake, northern Lower Michigan, USA, along with comparative pollen data from regional paleoecological sites and optically stimulated luminescence dates from inland sand dunes across the Great Lakes region, reveals emerging relationships among climate, vegetation, and erosion. Tsuga (hemlock) pollen was used to track local- and regional-scale hydroclimate variability owing to the taxon’s moisture sensitivity and close association with modern lake-effect snowfall gradients. Two periods of elevated MS and Tsuga values, 6800–5200 cal yr BP and 3200–800 cal yr BP, are interpreted as millennial-scale phases of greater effective moisture that drove key changes in forest composition and resulted in accelerated erosion. Overall, the lake’s MS record broadly tracks changes in Tsuga pollen frequencies and sedimentation rates, particularly during the Late Holocene, suggesting the emergence of a well-defined lake-effect climate system between 5200 and 1000 cal yr BP. Additionally, Pup Lake’s MS record exhibits notable connections with widely recognized hemispheric-scale climate deterioration episodes, including the 9.2, 8.2, and 5.2 ka BP events.

Ozette Lake, located on the Olympic Peninsula of western Washington, is ideally situated to provide a sedimentary record of past earthquakes along the northern portion of the Cascadia subduction zone. The lake stratigraphy is punctuated by turbidites, with characteristics typical of those triggered by earthquake shaking as seen in other lakes worldwide. Sediments deposited in Ozette Lake over the past 1300 years between earthquake events show decadal-scale variations in color, magnetic susceptibility, clay content, organic carbon content, density, and computed tomography (CT) intensity. Applying the dynamic time warping technique reveals a strong correlation of CT intensity to historical, instrumental measurements of regional cool-season precipitation, indicating that sediments in the lake preserve a high-fidelity record of decadally averaged fluvial sediment discharge and climate. Correlation of CT intensity patterns from older strata preserved deeper in the lake stratigraphy to two independent, regional paleo-precipitation reconstructions similarly suggests that the sediments record decadal variations in hydroclimate. We provide radiocarbon-independent dates for the past four northern Cascadia subduction earthquakes that are within the uncertainty of a radiocarbon age-depth model but are more precisely estimated by placing earthquake-triggered turbidites in the context of wet and dry periods in these tree-ring- and oxygen-isotope-based reconstructions. Paleoclimate-based constraints on the age of event layers in this and other regional lakes have the potential to help address ongoing questions about past ruptures on the Cascadia subduction margin.

Detrital sediments of the Sea of Galilee are predominantly pedogenic products of settled dust and local bedrocks transported from Upper Galilee and the Golan Heights. Using the mineralogy, chemistry, and Nd and Sr isotope ratios of the core LK12-22 collected offshore of the Ginosar valley and of contemporaneous soils from the Nahal Tzalmon and Nahal Amud catchments, we reconstructed Late Holocene regional hydroclimate. The core samples span ɛNd isotope values of −6 to −2 and 87Sr/86Sr ratios of 0.7075 to 0.7077 between the isotope fields of the Terra rossa soils and basaltic soils. Sediments from the drier Iron Age and Arabic and Ottoman periods are closer in Nd-Sr isotope ratios of the basaltic soils, while those of the wetter Middle to Late Bronze and Roman–Byzantine periods are closer to the Terra rossa soils, reflecting enhanced mobilization of sediments from the Tzalmon catchment where Terra rossa–type soils accumulated. This result corroborates other regional data that indicate semiarid to temperate conditions in the south Levant during most of the Late Holocene. Wetter conditions over the Galilee Mountains and the Ginosar valley catchment during the Roman period could have promoted the flourishing farming-fishing society that heralded the rise of Christianity.

The wettest portion of the interior of western North America centers on the mountainous region spanning western Montana, Idaho, British Columbia, and Alberta. Inland ranges there capture the remnants of Pacific storms. Steep east–west hydroclimate gradients make the region sensitive to changes in inland-penetrating moisture that may have varied greatly during the Holocene. To investigate potential hydroclimate change, we produced a 7600-yr lake-level reconstruction from Silver Lake, located on the Montana–Idaho border. Ground-penetrating radar profiles and a transect of four shallow-water sediment cores that were dated using radiocarbon dating and tephrachronology revealed substantial changes in moisture through time. An organic-rich mud unit indicating wet and similar to modern conditions prior to 7000 cal yr BP is overlain by an erosional surface signifying drier than modern conditions from 7000–2800 cal yr BP. A subsequent time-transgressive increase in water levels from 2800–2300 cal yr BP is indicated by a layer of late Holocene muds, and is consistent with glacier expansion and increases in the abundance of mesic tree taxa in the region. Millennial-scale trends were likely driven by variations in orbital-scale forcing during the Holocene, but the regional outcomes probably depended upon factors such as the strength of the Aleutian Low, Pacific sea-surface temperature variability, and the frequency of atmospheric rivers over western North America.

Ice-covered lakes in Antarctica preserve records of regional hydroclimate and harbour extreme ecosystems that may serve as terrestrial analogues for exobiotic environments. Here, we examine the impacts of hydroclimate and landscape on the formation history of Lake Eggers, a small ice-sealed lake, located in the coastal polar desert of McMurdo Sound, Antarctica (78°S). Using ground penetrating radar surveys and three lake ice cores we characterize the ice morphology and chemistry. Lake ice geochemistry indicates that Lake Eggers is fed primarily from local snowmelt that accreted onto the lake surface during runoff events. Radiocarbon ages of ice-encased algae suggest basal ice formed at least 735 ± 20 calibrated years before present (1215 C.E.). Persisting through the Late Holocene, Lake Eggers alternated between periods of ice accumulation and sublimation driven by regional climate variability in the western Ross Sea. For example, particulate organic matter displayed varying δ15N ratios with depth, corresponding to sea ice fluctuations in the western Ross Sea during the Late Holocene. These results suggest a strong climatic control on the hydrologic regime shifts shaping ice formation at Lake Eggers.

Multiproxy analysis of two sediment cores recovered from lagos Morrenas 3C and Ditkebi, located in the páramo of Costa Rica's Chirripó National Park, was undertaken to develop multidecadal-scale reconstructions of late Holocene fire regimes for the region. Analysis of macroscopic charcoal and sediment geochemistry (C%, N%, δ13C, δ15N, and C/N ratios) documents periodic burning of the páramo in Chirripó National Park during the past ~1700 yr. The charcoal records provide evidence of high fire frequency between AD ~560 and 720 and between AD ~980 and 1230. Severe fire episodes are reflected by a rapid increase in the flux of carbon (C) and nitrogen (N) from the surrounding catchment because of the volatilization of páramo vegetation. Additionally, δ15N, which sharply increases following local fire events, captures postfire changes in nutrient loading and, likely, the decadal-scale rate of postfire recovery of páramo vegetation. The consistently high δ13C and C/N values observed between AD ~700 and 1100 suggest an expansion of Muhlenbergia, a native C4 grass growing near shore, suggesting that the interval between AD ~700 and 1100, broadly corresponding to the Terminal Classic Drought and Medieval Climate Anomaly, was characterized by a decrease in effective moisture and temperature.

Long-term sediment and ground-penetrating radar data from Davis Pond, a small lake near the Hudson River valley, reveal past droughts in a historically humid region that presently supplies water to millions of people in and around New York City. A minimum of eleven sandy paleoshoreline deposits in the lake date from 13.4 to 0.6 cal ka BP. The deposits span 1500 to 200 yr between bracketing radiocarbon ages, and intrude into lacustrine silts up to 9.0 m below the modern lake surface in a transect of six sediment cores. Three low stands, ca. 13.4–10.9, 9.2 and 8.2 cal ka BP indicate low regional moisture balance when low temperatures affected the North Atlantic region. Consistent with insolation trends, water levels rose from ca. 8.0 cal ka BP to present, but five low stands interrupted the rise and are likely associated with ocean–atmosphere interactions. Similar to evidence from other studies, the data from Davis Pond indicate repeated multi-century periods of prolonged or frequent droughts super-imposed on long-term regional trends toward high water levels. The patterns indicate that water supplies in this heavily populated region have continuously varied at multiple time scales and confirm that humid regions such as the northeastern United States are more prone to severe drought than historically expected.

We provide sedimentological, geochemical, mineral magnetic, stable carbon isotope, charcoal, and pollen-based evidence from a guano/clay sequence in Gaura cu Muscă Cave (SW Romania), from which we deduced that from ~ 1230 BC to ~ AD 1240 climate oscillated between wet and dry. From ~ 1230 BC to AD 1000 the climate was wetter than the present, prompting flooding of the cave, preventing bats from roosting, and resulting in a slow rate of clay accumulation. The second half of the Medieval Warm Period (MWP) was generally drier; the cave experienced occasional flash flooding in between which maternity bat roosts established in the cave. One extremely wet event occurred around AD 1170, when Fe/Mn and Ti/Zr ratios show the highest values coincident with a substantial increase of sediment load in the underground stream. The mineral magnetic characteristics for the second part of the MWP indicate the partial input of surface-sourced sediments reflecting agricultural development and forest clearance in the area. Pollen and microcharcoal studies confirm that the overall vegetation cover and human land use have not changed much in this region since the medieval times.