Add 2 news posts: Nora defense & Sakari paper

Author: IceAgeEcologist

_posts/2024-05-01-NoraSchlenkerPhDDefense.md

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+layout: post
+title:  "Congratulations to Newly Minted Dr. Nora Schlenker!"
+date:   2025-05-01 12:00:00 -0700
+categories: media
+blurb:
+---
+Congratulations to Dr. Nora Schlenker for the successful defense of her PhD dissertation *Vegetation dynamics in a novel and rapidly changing world - using a biogeographical and palaeoecological lens.*  Nora passed her defense with flying colors, using data and concepts from the past to better understand how species will respond to current and future climate changes.
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+Nora is off to Aarhus University in Denmark for a postdoc, leaving in July, so it's exciting to see her move to the next stage of her career and scholarship.  Congratulations Nora!

_posts/2025-05-08-HolocenePaleoclimate.md

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+layout: post
+title:  "New Paper on the Drivers of Holocene Drying in North America"
+date:   2025-05-08 12:00:00 -0700
+categories: media
+blurb:
+---
+A new study just out in [Nature Communications](https://www.nature.com/articles/s41467-025-58685-7) provides new insights into the causes of past drying in central North America.  These long periods of aridity are best thought of as persistent and long-lasting shifts in the background state of the climate system, rather than brief disruptions such as droughts.  These long-lasting changes can have devasting impacts on forests, water availability and the water table, and agricultural societies.  Fossil pollen records, such as those collected at UW-Madison and compiled globally into the Neotoma Paleoecology Database, clearly show a period of sustained aridity in the Great Plains and Great Lakes regions, between approximately 8,000 and 5,500 years ago.  
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+Now, a new generation of paleoclimatic simulations from Earth system models, combined with networks of fossil pollen and other paleoclimatic indicators, strongly indicate that this midcontinental aridity were caused by the retreat of the Laurentide Ice Sheet and changes in insolation.  As the ice sheet melted, its effect on atmospheric circulation waned, causing a reduction of storm tracks though the north-central US.  In combination, intensified summer insolation during the early Holocene led to enhanced evaporative water loss and soil drying.  The patterns of drying produced by Earth system models when driven by these factors agree well with paleoclimatic data networks, suggesting that we are gaining an increasingly good understanding of why central North America dried out during the early to middle Holocene.
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+This work was led by Dr. Sakari Salonen at the University of Helsinki ([press release](https://www.helsinki.fi/en/news/climate-change/waxing-and-waning-prairie-new-study-unravels-causes-ancient-climate-changes)) with collaborators here at UW-Madison, Stockholm University, the University of Wyoming, and other institutions.