Annual meeting of the Society for American Archeology (SAA) 2021. Our small SeibalSim Project, in which we’re modeling the emergence of pre-Mayan cultural constructs during the Formative period, is going to give a presentation to the next SAA Annual Meeting in San Francisco, 14-18 April 2021.

Find a PDF version of the complete slide stack from the talk here.



I was invited to give a talk at the AGU Fall Meeting based on the paper I co-authored for Geography Compass with Emma Colven, assistant professor at the University of Oklahoma. The session “Climate Modeling for Everyone: Interdisciplinary Research to Address Social Justice and (More-Than) Human Impacts” (Session ID#: 102851) is going to be virtual, of course, as is AGU this year.

Abstract. The production and circulation of climate knowledge is mediated through interconnected but disparate systems of data acquisition, modeling, analytics, and communication. Complex synoptic models, such as general circulation models (GCMs) of the Earth’s climate or detailed process integrated assessment models (IAMs) to estimate the socio-economic impacts of climate change policy choices, are critical to this process but impractical to run at the spatial scale of human experience — that of a city, a valley, or a farm — or for hundreds of different parameter settings. Complex models can be statistically downscaled using exogenous information to infer higher spatial resolution. They are typically run according to standardized scenarios of emissions regulation and/or socio-economic development, such as the shared sustainability pathways (SSPs). Modelers make subjective choices throughout these processes that can be meaningfully enriched and democratized through interdisciplinary collaboration, with the potential to more effectively serve goals of social and environmental justice. These topics will be discussed in the context of collaborative IAM and scenario construction.

AGU is virtual this year, so there’s also a 3 minute audio presentation that I’ll later add a link for.



I was part of a discussion panel on behalf of the FABLE Consortium at the Global Forum on Innovations for Marginal Environments (GFIME) on 20-21 November in Dubai, UAE. The event is being put on by the International Center for Biosaline Agriculture in the UAE.

GFIME in Dubai. November 2019.

Our 5th FABLE Pathways Consortium Meeting will be held mid-November in Beijing, China.

I attended a workshop on the MAgPIE (Model of Agricultural Production and its Impact on the Environment) at PIK (The Potsdam Institute for Climate Impact Research) on 9-10 September. We were super impressed with the MAgPIE team at PIK and their work.


We will hold our 4th FABLE Pathways Consortium Meeting in Bogatá, Colombia, on 4-7 June. This follows the first publication from the Consortium principals in Nature a couple of weeks ago.


Update (07/2020): The paper was just published in Environmental Research Letters.

I’d planned to attend and present a paper at a conference in Kiel, Germany, “The Iternational Open Workshop 2019: Socio-Environmental Dynamics over the Last 15,000 Years: The Creation of Landscapes VI”, but could not make it. This is really too bad because it looks super-interesting! Fortunately, they accepted my paper for review among their conference proceedings, potentially for inclusion in a journal special issue. The paper is analyses the response of Fremont Ancestral Puebloans (Native American maize farmers in pre-contact Utah) to changes in season lengths (growing degree days, GDD) at the MCA-LIA transition I computed using temperature dailies from a statistically downscaled climate model. I also compared patterns from published proxy data to those in aggregated occupation information to show that the timing of Fremont occupation changes is consistent with proxy-derived climate changes.



I gave a presentation on the first FABLE Scenathon (“Scenathon: First Results of a Model-Aided, Structured Negotiation for Convergence Towards Global Sustainability Goals”) in Session GC42C: Linkages Between Climate Policies and Multiple Sustainable Development Goals I of the AGU Fall Meeting, on 13 December in the Walter E. Washington Convention Center, Salon B, Washington, D.C.

agu 2018 presentation


I gave a short talk and poster presentation at the “Climates and Cultures: Perspectives for the Future” conference, put on by the Royal Academy for Overseas Sciences of Belgium between 23-24 May, at the Palace of the Academies in Brussels. I showed the results of maize yield reconstruction studies for the Fremont Ancestral Puebloans of Utah done in conjunction with colleagues at IIASA.

That feeling you get when you mistakenly make your poster too big.

The conference was an interesting, interdisciplinary gathering with hydrologists, engineers, geographers, archaeologists, atmospheric scientists, and medical doctors attending to present on a variety of subjects connected by the theme of climate change, particularly in the past. Programme highlights for me included a fascinating re-examination of textual evidence of paleohydroclimatic changes in Egypt between the Old Kingdom and First Intermediate Period by John Darnell, professor of Egyptology at Yale (i.e., if one does not look exclusively for failed Nile floods, texts indicate a “weird” climate of disrupted wind patterns, possibly low floods, and different precipitation regime around the 4.2 ka event); learning about a reconstruction of North Atlantic winter sea surface temperature (from winter sea ice extent) from historical texts given by Astrid Ogilvie of INSTAAR; an attempt by historical linguists and archaeologists to rectify differences in records and explain the Bantu Expansion from West Africa in terms of environmental change, given by Koen Bostoen and Dirk Seidensticker of Ghent University; a back-to-basics approach to building sustainable cities for the future by Han Verchure, emeritus professor from KU Leuven; and an unflinchingly genetic-determinist(?) presentation of human migration since the earliest emergence from Afria by Joris Delanghe of Ghent University.



I gave a talk at the AAG Annual Meeting in Boston. I will present crop modeling from IIASA and proxy records from Utah, including charcoal and chironomid-inferred temperature for the MCA-LIA transition, in New Records of Paleoenvironmental Change (4.40 – 6.20 PM) on 5 April in Salon H, the Marriott; a session sponsored by the Paleoenvironmental Change Specialty Group.

Screenshot 2017-05-09 at 22.40.41




I presented a poster at the AGU Fall Meeting 2016 in San Francisco. “Crop Model Simulated Impact of Climate Change on Fremont Native American Maize Farming in Utah at the MCA-LIA Transition Using a Downscaled GCM,” during the morning poster session (8 AM – 12.20 PM) on 15 December in Moscone South (Session and number, PP41C-2253). It will be among the Climate of the Common Era I posters.


I will be at this year’s biennial Mountain Climate Conference (MtnClim2016) in Leavenworth, WA, (17-20 October). This is a small conference with researchers interested in the climate and environment of the Western US. Really looking forward to it! Agenda.


I spent 3 months over summer 2016 as a Young Scientist Summer Program fellow (“YSSPer“) at the International Institute of Applied Systems Analysis (IIASA) in Laxenburg, Austria. I worked under economist Dr. Tamas Krisztin and soil scientist Dr. Juraj Balkovic, in the Ecosystem Services and Management (ESM) group and developed a method to drive a soil productivity model for Zea mays with my statistically downscaled GCM climatologies for 850-1449 CE. I met some amazing young scientists who aim to do good in the world, 2 ex-presidents from the EU, the Tyrolian Alps and nearly more beer and sausages than I could handle.


At the end of our time at IIASA, all of the YSSPers gave a presentation on the work they had carried out that summer. I showed how we had used the EPIC crop productivity model to estimate maize harvests for Fremont Ancestral Puebloans through the MCA-LIA transition. Photo: M. Xylia.


We spent some remarkable time hiking in the Tyrolian Alps. But I was amazed that we missed mountain glaciers and multi-year snow (that we expected to cross) by a few years — alpine ice is retreating so quickly that our hikers’ map was already out of date. Photo: L. Eloul.


I gave a talk on my dissertation research at the Association of American Geographers (AAG) 2016 annual meeting in San Francisco (29 March – 2 April).”Climate, Corn and Collapse? A Paleoclimate Model and Proxy Based Analysis of Native American Agricultural Decline in Prehistoric Utah” in the New Records of Paleoenvironmental Change II session, on Wednesday, 30 March at 10:20 AM.

   Abstract: The ancestral Puebloan (“Fremont”) peoples of Utah represent the northernmost extension of a corn (Zea mays) based culture in the prehistoric Southwest. Unlike Pueblo dwellers of New Mexico and Arizona (presumed descendants of ancestral Puebloans to the south), the Fremont and their horticultural practices had vanished from Utah by the time of Spanish contact. Can the rise and decline of Fremont agriculture be correlated with large-scale changes in Northern Hemisphere climate and could such changes be of sufficient magnitude to plausibly impact maize agriculture? We use statistical downscaling of CESM-CAM5 Last Millennium Ensemble (LSE) climate models to reconstruct maize-farming conditions in Fremont occupation sites in Utah over the last ~1200 years, with particular attention to the Medieval Climate Anomaly (MCA, ca. 850 to 1350 CE ) and Little Ice Age (LIA, ca. 1350 to 1850 CE) transition. We also analyze multiple lake sediment proxies to test the veracity of the downscaled models. Based on these analyses we demonstrate spatiotemporal redistributions of C14-dated Fremont sites consistent with sub-regional warming patterns through the MCA and cooling patterns to the MCA-LIA transition.


Presenting a time series of Fremont occupation sites by elevation, in the Uinta Basin. Hilton Hotel Union Square, San Francisco, 30 March 2016. Image: Jiaying Wu.



Poster draft for AGU

I presented at the American Geophysical Union (AGU) 2015 Fall Meeting in San Francisco (14-18 December) as part of the Climate of the Common Era (past 2000 years). “Using Stochastically Downscaled Climate Models and Multiproxy Lake Sediment Data to Connect Climatic Variations Over the Past 1000 Years and the History of Prehistoric Maize Farming in Utah”.

I attended the Association of Pacific Coast Geographers (APCG) 2015 Annual Meeting in Palm Springs (21-24 October). I presented a poster with my co-author and student lab researcher Elly Fard, who will join the MacDonald Lab as a new graduate student in the fall.

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