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A Climate Story from the Marsh
Tue Jul 19, 2005
Listen in RealAudio 
If you thought that marshes were good for only blackbirds, black flies, and bullrushes, prepare to be surprised; they are also excellent climate recorders. Hi, I’m Bryan Yeaton, and this is The Weather Notebook’s Climate Change series.
Researchers from Columbia University and NASA have been looking at Piermont Marsh in New York’s Hudson River Valley, and learning that it has been an excellent chronolog of the local climate. Core samples, just like those from glacial ice or the ocean floor, have been pulled from the Piermont, less than 20 miles upstream from downtown Manhattan. Seeds and pollens trapped in the sediment can tell us what types of vegetation were thriving there in various time periods.
The researchers, Dee Peterson and Dorothy Peteet, deduced a period of drought from around the years 800 to 1300 AD, signified not only by an increase in charcoal, which is a sign of drought-induced fires, but also the dominance of pine and hickory pollens. In wetter climates, more oak trees would prevail. These dates also match up quite well with the Medieval Warm period, which is dated from 950-1250 AD.
The scientists were also able to find evidence of the Little Ice Age, which occurred from about 1550-1850. They noted an increase of conifers such as spruce and hemlock, which thrive in a cooler and wetter climate.
This research is important because it gives us an indication of what this part of the natural world was like before the influx of European settlers. These settlers altered the climate by clearing trees for cattle and agriculture. The study was also funded by the Hudson River Foundation, and Columbia University’s Lamont-Doherty Earth Observatory (LDEO).
The Weather Notebook is a program of the Mount Washington Observatory. Find all of our past shows online at www.weathernotebook.org. We are supported by Subaru of America, with funding for this series provided by Environmental Defense.
Today's Links
Medieval Marsh
http://www.nasa.gov/vision/earth/lookingatearth/medieval_marsh.html.
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