Kevin Anchukaitis | The Past Landscapes Lab

My lab's research program focuses on identifying, understanding, and interpreting forced and unforced variability in the climate system on timescales from extreme events to long-term trends. We develop improved, quantitative, and objective estimates of climatic variability and change -- often using paleoenvironmental proxies, statistical reconstructions, modeling -- to identify and understand both natural and anthropogenic processes and influences on the earth system. Information about the long-term and low-frequency behavior of the climate system, as well as its response to perturbations and its potential range of variability, are necessary for projecting the future response of the climate system to anthropogenic forcing. We also investigate the dynamic response of socio-ecological systems to climate and environmental change across a range of time and spatial scales.

You can learn more about all the members of our lab on the People page.

Recent News

• Kevin, lab alumnus Dr. Jessie Pearl, and other LTRR colleagues were featured in this Boston Globe article about how tree record climate variability and change, and how in turn they are responding to those changes.
• We have two new NSF-funded projects in the lab! The first from NSF P4CLIMATE will allow us to study the behavior of the ITCZ over the last several centuries using oxygen isotopes in tropical trees from both hemispheres in the Americas. The second is also from NSF's P4CLIMATE and is led by Dr. Karen King at the University of Tennessee. We'll be using the blue intensity tree-ring proxy to reconstruct temperature variability in time and space across North America.
• Congratulations to Dr. Talia Anderson and Dr. Julie Edwards, who defended their dissertations and received their Ph.Ds in summer 2024! Dr. Edwards takes her NSF postdoctoral fellowship to UC Santa Barbara working with Dr. Joan Dudney and Dr. Samantha Stevenson, while Dr. Anderson takes her NOAA Climate and Global Change postdoctoral fellowship to UCLA and Dr. Karen McKinnon's lab. We miss them already!
• Park Williams leads a new paper in Journal of Geophysical Research where we show, despite some recent wet winters, that the signal of anthropogenic influence on extreme cool season precipitation has not yet emerged in the western United States.
• We have a new paper in Journal of Climate using paleoclimate reconstructions to examine the concurrent 2010 Russian heatwave/Pakistan flooding in a long-term context.
• We have a new paper critiquing the IPCC's use of a single Common Era paleoclimate reconstruction. Our paper provides greater context for what we know (and not know) about the climate of the last 2000 years and suggests ways the IPCC can improve in the future.
• There is a new round of Haury Visiting Scholar & Trainee Fellowships available with a deadline of May 15, 2024 for applications. If you'd like to spend some time in our lab between September 2024 and May 2026, please contact Kevin to make a plan for your application.
• We have a new article in Climate Dynamics building and evaluating spatial reconstructions of drought severity across the Mediterranean Basin over the last 1000 years.
• Karen King leads an exciting new paper in Science Advances showing the recent 'hot droughts' in the western United States are exceptional in the context of the last five centuries. The paper was featured in the Washington Post, CNN, and on NPR.
• We have a new paper in Journal of Climate led by Park Williams showing that apparent cyclicity in Sierra Nevada winter precipitation is driven by the characteristics of atmospheric rivers
• Dimitris Herrera leads a new review paper in PLoS Climate about observed human influences on global hydroclimate
• Talia Anderson leads a new paper in Geophysical Research Letters on the 2015-2019 Central American drought. We find that while this drought was extremely severe, it falls within the range possible from natural climate variability. July through August deficits were the most significant drivers of overall drought, pointing to the importance of variability in the Midsummer Drought. We also find that positive easterly zonal wind anomalies associated with the Caribbean Low-Level Jet are strongly linked to regional precipitation deficits.
• Andrea Burke leads a new paper in Proceedings of the National Academy of Sciences using sulfur isotope to quantify the stratospheric component. We find evidence that several of the coldest decades in the last two thousand years—linked with major climatic and societal disruption—were driven by a relatively small amount of stratospheric sulfate from high-latitude eruptions.
• Kevin was awarded the 2023 Willi Dansgaard Award from the American Geophysical Union for 'significant contributions to the fields of paleoceanography or paleoclimatology from a mid-career scientist'
• The paper describing our DASH data assimilation software package led by former graduate student Jonathan King is now published in Geoscientific Model Development.
• Feng Zhu leads a new paper that creates a pseudoproxy network based on the PAGES2k database for testing and evaluating climate reconstruction methods.
• Lea Schneider leads a new paper comparing gridded temperature products with tree-ring reconstructions for the 19th century. Where stations are sparse but tree rings are good recorders of summer temperature, we show that colder temperatures likely mean that the threshold for 1.5C warming above 'preindustrial' is closer than we think.
• We have a new paper in Water Resources Research placing the 2015 snow drought in the Oregon Cascades in the context of variability over the last several centuries.
• We have a new paper out in Nature Communications using paleoclimate data assimilation to reconstruct variability in the Southern Annular Mode (SAM) over the Common Era using a multiproxy network of trees and ice cores. We find that the SAM was dominated by unforced internal variability across a range of time scales over most of the last 2000 years, until recent decades where the upward trend is outside the 2 sigma range of variability over the previous 2 millennia. This is the third chapter from Jonathan King's dissertation and was funded by a grant from the NSF P2C2 program.
• Karen Heeter (now at the Tree-Ring Lab at Lamont-Doherty Earth Observatory) leads a new paper where we show that that the blistering summer temperatures that accompanied the 2021 heatwave across the Pacific Northwest were unprecedented in the context of the last millennium.
• We have two new papers arising from our NSF grant on the Southern Annular Mode (SAM) during the Common Era. Graduate student Zack Grzywacz leads a paper looking at whether stable isotopes in Tasmanian tree rings can help reconstruct SAM variability, and graduate student Meagan Walker shows that high resolution radiocarbon measurements can be used to confirm crossdating in subfossil tree-ring chronologies with low sample depth.
• We have a new Dynamics of Socio-Environmental Systems (DISES) grant from the NSF! Our project on Indigenous forest management in a non-stationary climate seeks to understand how traditional and Indigenous knowledge systems adapt to climate and social change.
• Led by Charlotte Pearson, we've been awarded an NSF Major Resource and Instrumentation grant to purchase and run a new MICADAS radiocarbon system at the Laboratory of Tree-Ring Research!
• Ben Cook leads a new paper in Nature Reviews Earth and Environment on megadroughts in the Common Era and the Anthropocene.
• We have a new review article on the History of Climate and Society - the intersection of paleo/climate and paleo/environmental science, history, archaeology, genetics, and geography that seeks multidisciplinary ways to understand the interactions between climate variability and change and the response by and feedbacks with human societies.
• The Past Landscapes Lab welcomes two new members! Ellie Neifeld has a Bachelors in Earth and Oceanographic Science from Bowdoin College and will be working on high-latitude climate changes in North America for her Masters. Ana Isabel Gonzalez Mendez has a Bachelors in Environmental Engineering from Universidad Rafael Landivar and then worked as the Coordinator for the Climate Change unit in Guatemala's Instituto Nacional de Sismología, Vulcanología, Meteorología e Hidrología. Her Masters research will focus on climate variability and change in Central America. Welcome!
• Congratulations to Kira Harris, who successfully defended her Masters thesis on a late Holocene reconstruction of sea surface temperatures in the Gulf of California. Kira now moves onto the Ph.D. program here in the School of Geography, Development, and Environment!
• Congratulations to Dr. Jonathan King, who was awarded his Ph.D. in Geosciences in Spring 2022! Jonathan's dissertation used data assimilation to investigate the climate of the Common Era. He starts a USGS Mendenhall postdoctoral fellowship in Fall 2022 in Golden, Colorado!
• Kevin has a new paper with Jason Smerdon providing a review of progress in reconstructing large-scale temperatures over the Common Era, identifying persistent and extant challenges for these reconstructions, and critiquing the IPCC for featuring a single reconstruction in the AR6 report and therefore not adequately representing what we know — and more importantly don't know — about the climate of the last 2000 years. The paper is 'Progress and uncertainties in global and hemispheric temperature reconstructions of the Common Era' is is open access.
• Feng Zhu leads a new paper where we re-evaluate the link between volcanic eruptions and ENSO. We find (1) only a weak statistical association between volcanism and ENSO and (2) that the selection of volcanic events in the analysis is a key variable to which the inference is highly sensitive. We conclude that it is not possible to make any confident conclusions from the current last millennium paleoclimate record about the contribution of volcanic eruptions to ENSO dynamics.
• Julie Edwards leads a new paper investigating the erroneous cooling reconstructed from northern European trees during the 1783 eruption of Laki in Iceland. Using multiple lines of evidence, Julie shows this discrepancy is likely due to the direct impacts of acidic haze on trees.