About

Anthony Clarke is a faculty member at Columbia GSAPP. The page does not provide specific details about his research focus, background, or key contributions. Therefore, no further biographical information is available from the provided content.

Research topics

• Geology
• Ecology
• Physical geography
• Geography
• Environmental science
• Climatology
• Oceanography
• Archaeology
• Biology

Selected publications

• Internal variability can overwhelm the forced precipitation response pattern over western North America

  2025-10-20

  articleOpen access1st authorCorresponding

  State-of-the-art Earth system models project 21st-century winter precipitation trends of varying sign over western North America. We quantify the influence of internal variability on these precipitation changes in an initial-condition large ensemble from one global Earth system model. We decompose winter precipitation change into thermodynamic and dynamic components and find that thermodynamics explain the ensemble mean precipitation response. Yet, dynamics drive a large range of response patterns because of differences between individual ensemble members due to internal variability. To better understand and classify these patterns, we use a machine learning algorithm called self-organizing maps. While the forced precipitation response is a modest precipitation increase across the region, precipitation decreases over California in 28% of the members due to dynamics. Precipitation increases across California in the remaining members. These findings reinforce the notion that internal variability can overwhelm the forced precipitation response and lead to long-lived precipitation decreases in the future.

  PublisherOA PDFDOI

• Revealing past climate variability using tree rings and stable isotopes from tropical and boreal regions in the Americas

  2025-03-15

  preprintOpen access

  High-resolution records of centennial climate variability are crucial considering the scarcity and overall short length of instrumental meteorological data in many regions of the world. The application of stable isotopic analysis in tree rings has emerged as a robust methodological tool for elucidating the intricate complexities of environmental history. This presentation will travel from high latitudes in North America to the Tropical Andes in South America to show how tree-ring stable isotopes can be used to reconstruct climate variability and atmospheric patterns across the Americas, as well as changes in Sea Surface Temperatures (SST). Stable oxygen isotopes (δ18O) measured in tree rings from white spruce trees from the Northwest Territories of Canada record similar large-scale climate patterns as modelled precipitation δ18O from a general circulation model (NASA GISS ModelE2 isotopically-equipped). Trees from the species Polylepis tarapacana growing at high elevation (~5,000 m a.s.l) at the South American Altiplano were used to reconstruct annual precipitation variability, which is driven by the South American Summer Monsoon, over the last 300 years. This newly developed tree-ring δ18O chronology revealed a robust hydroclimatic teleconnection showing interannual (2–5 years) and decadal (~11 years) periodicities consistent with records of Altiplano precipitation, central tropical Pacific SST, Andean ice core δ18O and tropical Pacific coral δ18O. Furthermore, new tree species of the genus Polyelpis growing in the inner tropics were discovered and found to have significant sensitivity to local and regional hydroclimate variability, showing a close link to tropical Pacific SST and El Niño–Southern Oscillation. Overall, our findings point out the importance of developing longer stable isotopes tree-ring records to overcome the inherent difficulties to reconstruct global hydroclimate variability. 

  PublisherDOI

• Megadroughts in the Common Era and the Anthropocene

  UNC Libraries · 2025-04-17

  articleOpen access
  PublisherDOI

• Anthropogenic Intensification of Cool‐Season Precipitation Is Not Yet Detectable Across the Western United States

  Journal of Geophysical Research Atmospheres · 2024-06-11 · 11 citations

  articleOpen access

  Abstract The cool season (November–March) of 2022–2023 was exceptional in the western United States (US), with the highest precipitation totals in ≥128 years in some areas. Recent precipitation extremes and expectations based on thermodynamics motivate us to evaluate the evidence for an anthropogenic intensification of western US cool‐season precipitation to date. Over cool seasons 1951–2023, trends in precipitation totals on the wettest cool‐season days were neutral or negative across the western US, and significantly negative in northern California and parts of the Pacific Northwest, counter to the expected net intensification effect from anthropogenic forcing. Multiple reanalysis data sets indicate a corresponding lack of increase in moisture transports into the western US, suggesting that atmospheric circulation trends over the North Pacific have counteracted the increases in atmospheric moisture expected from warming alone. The lack of precipitation intensification to date is generally consistent with climate model simulations. A large ensemble of 648 simulations from 35 climate models suggests it is too soon to detect anthropogenic intensification of precipitation across much of the western US. In California, the 35‐model median time of emergence for intensification of the wettest days is 2080 under a mid‐level emissions scenario. On the other hand, observed reductions of precipitation extremes in California and the Pacific Northwest are near the lower edge of the large ensemble of simulated trends, calling into question model representation of western US precipitation variability.

  PublisherOA PDFDOI

• A Virtual Expedition to the Juneau Icefield

  GSA Today · 2024-08-02

  articleOpen access
  PublisherDOI

• Atmospheric Rivers are Responsible for Cyclicity in Sierra Nevada Precipitation

  Journal of Climate · 2024-01-05 · 3 citations

  articleOpen accessSenior author

  Abstract Cool-season (November–March) precipitation contributes critically to California’s water resources and flood risk. In the Sierra Nevada, approximately half of cool-season precipitation is derived from a small proportion of storms classified as atmospheric rivers (ARs). The frequency and intensity of ARs are highly variable from year to year and unreliable climate teleconnections limit forecasting. However, previous research provides intriguing evidence of cycles with biennial (2.2 years) and decadal (10–20 years) periodicities in Sierra Nevada cool-season precipitation, suggesting it is not purely stochastic. To identify the source of this cyclicity, we decompose daily precipitation records (1949–2022) into contributions from ARs versus non-ARs, as well as into variations in frequency and intensity. We find that the biennial and decadal spectral peaks in Sierra Nevada precipitation totals are entirely due to precipitation delivered by ARs, and primarily due to variations in the frequency of days with AR precipitation. While total non-AR precipitation correlates with sea surface temperature (SST) and atmospheric pressure patterns associated with the El Niño–Southern Oscillation, AR precipitation shows no consistent remote teleconnections at any periodicity. Supporting this finding, atmospheric simulations forced by observed SSTs do not reproduce the biennial or decadal precipitation variations identified in observations. These results, combined with the lack of long-term stable cycles in previously published tree-ring reconstructions, suggest that the observed biennial and decadal quasi-cyclicity in Sierra Nevada precipitation is unreliable as a forecasting tool. Significance Statement In California’s Sierra Nevada, where most of the state’s above-ground water resources originate, cool-season precipitation totals exhibited year-to-year and decadal cyclicity over the past century. Long-range forecasts are notoriously unskillful in this region, so nonrandom cycles would be intriguing to water managers challenged to simultaneously minimize flood and drought risk. Over 1949–2022, precipitation cycles were driven by variations in the number of atmospheric river (AR) storms per year even though ARs account for just half of total precipitation. These findings bring us a step closer to understanding the causes of precipitation cyclicity, but we find no evidence that the cycles were underpinned by larger-scale ocean–atmosphere circulations so we caution against relying on continued cycles into the future.

  PublisherOA PDFDOI

• The Laurentide Ice Sheet in southern New England and New York during and at the end of the Last Glacial Maximum: a cosmogenic-nuclide chronology

  Climate of the past · 2024-09-26 · 5 citations

  articleOpen accessSenior author

  Abstract. We present 40 new 10Be exposure ages of moraines and other glacial deposits left behind by the southeastern sector of the Laurentide Ice Sheet (LIS) in southern New England and New York, summarize the regional moraine record, and interpret the dataset in the context of previously published deglaciation chronologies. The regional moraine record spans the Last Glacial Maximum (LGM), with the outermost ridge of the terminal complex dating to ∼ 26–25 ka, the innermost ridge of the terminal complex dating to ∼ 22 ka, and a series of smaller recessional limits within ∼ 50 km of the terminal complex dating to ∼ 21–20.5 ka. The chronology generally agrees with independent age constraints from radiocarbon and glacial varves. A few inconsistencies between ages from cosmogenic-nuclide measurements and those from other dating methods are explained by geological scatter, where several bedrock samples and boulders from the outer terminal moraine exhibit nuclide inheritance, while some exposure ages of large moraines are likely affected by postdepositional disturbance. The exposure age chronology places the southeastern sector of the LIS at or near its maximum extent, from ∼ 26 to 21 ka, which is broadly consistent with the LGM sea-level lowstand, local and regional temperature indicators, and local summer insolation. The net change in LIS extent, represented by this chronology, occurred more slowly (< 5 to 25 m yr−1) than the subsequent retreat through the rest of New England, consistent with a slow general rise in insolation and modeled summer temperature. We conclude that the major pulse of LIS deglaciation and accelerated recession, recorded by dated glacial deposits north of the moraines discussed here, did not begin until after atmospheric CO2 increased around 18 ka, marking the onset of Termination I.

  PublisherOA PDFDOI

• The Laurentide Ice Sheet in southern New England and New York during and at the end of the Last Glacial Maximum – A cosmogenic-nuclide chronology

  2024-02-01 · 1 citations

  preprintOpen accessSenior authorCorresponding

  Abstract. We present 40 new 10Be exposure ages of moraines and other glacial deposits left behind by the southeastern sector of the Laurentide Ice Sheet (LIS) in southern New England and New York, summarize the regional moraine record, and interpret the dataset in the context of previously published deglaciation chronologies. The regional moraine record spans the Last Glacial Maximum (LGM), with the outermost ridge of the terminal complex dating to ~26–25 ka, the innermost ridge of the terminal complex dating to ~22 ka, and a series of smaller recessional limits within ~50 km of the terminal complex dating to ~21–20.5 ka. The chronology generally agrees with independent age constraints from radiocarbon and glacial varves. A few inconsistencies among ages from cosmogenic-nuclide measurements and those from other dating methods are explained by geologic scatter where several bedrock samples and boulders from the outer terminal moraine exhibit nuclide inheritance, while exposure ages on large moraines are likely affected by postdepositional disturbance. The exposure-age chronology places the southeastern sector of the LIS at or near its maximum extent from ~26 to 21 ka, which is broadly consistent with the LGM sea-level lowstand, local and regional temperature indicators, and local summer insolation. The net change in LIS extent represented by this chronology occurred more slowly (<5 to 25 m yr-1) than retreat through the rest of New England, consistent with a slow general rise in insolation and modeled summer temperature. We conclude that the major pulse of LIS deglaciation and accelerated recession, recorded by dated glacial deposits north of the moraines discussed here, did not begin until after atmospheric CO2 increased at ~18 ka, marking the onset of Termination 1.

  PublisherDOI

• Supplementary material to "The Laurentide Ice Sheet in southern New England and New York during and at the end of the Last Glacial Maximum – A cosmogenic-nuclide chronology"

  2024-02-01 · 1 citations

  preprintSenior author
  PublisherDOI

• A 300-year tree-ring δ18O-based precipitation reconstruction for the South American Altiplano highlights decadal hydroclimate teleconnections

  Communications Earth & Environment · 2024-05-21 · 14 citations

  articleOpen access

  Abstract Tropical South American climate is influenced by the South American Summer Monsoon and the El Niño Southern Oscillation. However, assessing natural hydroclimate variability in the region is hindered by the scarcity of long-term instrumental records. Here we present a tree-ring δ 18 O-based precipitation reconstruction for the South American Altiplano for 1700–2013 C.E., derived from Polylepis tarapacana tree rings. This record explains 56% of December–March instrumental precipitation variability in the Altiplano. The tree-ring δ 18 O chronology shows interannual (2–5 years) and decadal (~11 years) oscillations that are remarkably consistent with periodicities observed in Altiplano precipitation, central tropical Pacific sea surface temperatures, southern-tropical Andean ice core δ 18 O and tropical Pacific coral δ 18 O archives. These results demonstrate the value of annual-resolution tree-ring δ 18 O records to capture hydroclimate teleconnections and generate robust tropical climate reconstructions. This work contributes to a better understanding of global oxygen-isotope patterns, as well as atmospheric and oceanic processes across the tropics.

  PublisherOA PDFDOI

Frequent coauthors

• Park Williams

  University of California, Los Angeles

  50 shared

• Kevin J. Anchukaitis

  University of Arizona

  25 shared

• Jason E. Smerdon

  Lamont-Doherty Earth Observatory

  25 shared

• Mukund Palat Rao

  Centre for Research on Ecology and Forestry Applications

  17 shared

• Valérie Daux

  Laboratoire des Sciences du Climat et de l'Environnement

  16 shared

• Laia Andreu‐Hayles

  Lamont-Doherty Earth Observatory

  15 shared

• Milagros Rodríguez‐Catón

  University of California, Davis

  14 shared

• Brian Medeiros

  NSF National Center for Atmospheric Research

  14 shared

Labs

• Anthony ClarkePI

Education

• M.S.

  Columbia University Graduate School of Architecture, Planning and Preservation