The New Sea Level Blues: Historical Science and Big Picture Views

News Flash: “Global crisis may hit home”.  The banner below the right margin headline in the Albany Times Union (June 25, 2017) read “Rising sea levels could drive a wave of refugees upstate from New York’s coastal areas”.  This article by Brian Nearing deals with the research of Charles Geisler, a Cornell University professor of development sociology.  The implication of sea level rise is that coastal people will be driven inland to find new homes.

I thought about it.  It reminded me of what I had been collecting information about this spring:  the effect of sea level rise on Archaic period Indians in northeastern North America.  I thought about my research.  Soon I was in the kind of prolonged reverie that historical scientists drift into when trying to piece together the almost infinitely detailed Big Picture.  Years ago, in Basin and Range, John McPhee (1981) led his readers on a special tour of this mind state.

Historical science: I had been intrigued for years by methods and metaphors held in common by the branches of science including geology, paleontology, cosmology, and archaeology that rely upon truly long views of the past.  Deep time, as McPhee called it.  Deep Time.  More a metaphor than a specific age.  Enough time for the earth’s history to unfold, and according to my interest, for human history to unfold.  I was just reading about constructing these deep histories in an old book review by Stephen Jay Gould (1987):

“Just as archaeologists might use tree-rings of support beams, styles of pottery or forms of axheads to order a group of widely scattered pueblos into a temporal sequence” Gould mused, “geologists needed, above all else, a criterion of history.”  

Damn right they did.  And their first criterion (early geologists learned in the 1830s) was the reliability of changes in the fossil record.  The artifacts archaeologists study change for different reasons than organisms, but the same powerful metaphors (such as deep time) have broad utility.  Historical scientists reconstruct the history of the world, humanity, and the cosmos.     

My mind wandered some more.  I thought “Of course the long perspective is that the reality of sea level rise isn’t new.”  Sea level has been rising for thousands of years.  But in the history of the United States, sea level rise has been so gradual that it often has gone unnoticed, at least by most people.  Global sea level has come up about 8 inches in the last 100 years, although it was slower 100 years ago, and has been accelerating in recent decades.

Not so during the deep time of human history on the North American continent, for in the ancient days more than about 4,000-5,000 years ago, the changes were considerably more drastic.  And the newcomers from the inundated coastal plain and the local communities in the area now upstate New York, suddenly neighbors, needed to find ways to move into the future together. 
I still held the paper in my hands.  I skipped ahead to see if the article had anything to say about the upper Hudson Valley--  Albany, Troy, Saratoga Springs, Glens Falls--  places in my own backyard.

“Tidal as far as Troy” Nearing observed, “the Hudson could further rise between an inch and nine inches during the 2020s, according to figures adopted this spring by the state Department of Environmental Conservation.”  I reflected on what I just read.  Compared to 8 inches in the last hundred years, 9 inches in the next 10 or so is an awful lot.  It sounds like the rapid sea-level rise of 8000-10,000 years ago.  I read on. There would be a continued rise of 5-27 inches into the 2050s.  The statistics piled up, with admittedly a wide range of predictions due to the big unknown:  how much would greenhouse gas emissions be curtailed as awareness of the problem grows and the nations of the world assert the necessary will power?  By 2100, as little as 10 inches or as much as 6 feet rise would occur at the Albany-Troy end of the Hudson’s estuary, depending upon whether greenhouse gas emissions are curtailed.  The AD 2100 prediction for New York City is 15-75 inches, again, depending in part upon human activity.  Not idle speculation, these reportedly are the data the State of New York is using to prepare.

I looked out the window.  No water in sight (but I’m in a high and dry place).  The Hudson indeed is a tidal river south of Troy.  A writer of its history, Robert Boyle (1979), remarked that water from the upper Hudson region only slowly reaches the ocean, because for every eight feet the river flows downstream, the tide flows back seven.  I don’t know if this is true all the time (there may be some poetic license going on here), but you get the point.  

I used to live next to the river in Castleton, New York.  In the scene out my back door, cormorants on posts, fishing herons standing in the low tide, the rising and falling Hudson was part of the rhythm of everyday life.  The Hudson is an estuary from New York City to the Federal Dam at Troy, built in 1915.  The great New York State Archaeologist Robert E. Funk (1976:6) noted that the typical tidal range at Troy (low to high or vice versa) is over 5 feet.  

The Hudson River estuary between Coxsackie and Athens, looking up stream on an autumn day.

The Hudson River estuary between Coxsackie and Athens, looking up stream on an autumn day.

Sea level has risen a few more inches since 1915.  You can’t eyeball the difference year to year, but the rising water over thousands of years has put the river bottom well below sea level and engulfed a great deal of floodplain (a striking example being Esopus Meadows; Eisenberg 1982:21).  Rising sea level over thousands of years is the effect of melting glacial ice since the world’s climate turned warmer in the late Pleistocene epoch.  Since those early days, sea level rise has slowed down.  For a long time, at New York’s latitude the rise in sea level greatly exceeded the rate at which the continent rebounded upward when the weight of glacial ice was removed.  Also, the climate has been turning cooler over most of the last 3500 years than it had been in the previous 6500.  Nonetheless, sea level rise never stopped, and recently it has accelerated again.  Hence the rising sea level blues. 

On the coastal plain, the scale of inundation was massive.  While the last Ice Age was ending and glaciers were melting, the rising sea level began inundating the ancient lower Hudson Valley, a place now far out at sea.  The Hudson and other rivers once cut through a wide coastal plain.  Now all of that, river valley and coastal plain, is under water.  It has become the east coast’s continental shelf.  Farther inland, rising sea level covered the Hudson’s floodplains progressively, taking habitable and forage-able land away from people, and submerging the home sites that they and their ancestors had lived in from time immemorial.  The rising water submerged not only the valley but also the upland portions of the coastal plain, reaching high ground around New York City (where its continuing rise has become a great matter of 21st century concern).  

The water continued to rise where it could, seeking its level, flooding narrower landscapes along the Hudson and other rivers flowing to the Atlantic.  The sea refuses no river, but it has been a dynamic relationship over the long course of Holocene history.  Brackish water reaches Poughkeepsie, and oyster shell from an archaeological site in that area shows it has done so for thousands of years (Funk 1991).  The archaeologist Daria Merwin (2010:93-96) has found Native American artifacts in the Hudson River near Croton Point.  They are considered most likely to be from an inundated archaeological site.  The submerged old ground surface here appears to have been inundated wetlands about 2500 years ago and dry land somewhat earlier.  The geologist Robert Dineen (1996) has noted that since about 10,000 years ago, the river has risen 160 feet at Tarrytown on the lower Hudson.  In the upper Hudson, the estuary advanced to rocky rapids at Castleton (some 10 miles below Albany) by about 8000 years ago.  Then, invading the last stretch it would flood in the upper Hudson region, it reached the rapids at Troy about 4000 years ago.   

Sea meets land at Cape Cod near Sandwich, Massachusetts.

Sea meets land at Cape Cod near Sandwich, Massachusetts.

The “Big Picture” grows bigger.  What happened in the Hudson Valley is only part it.  Trawlers, dredgers, and clammers have been bringing things up from the submerged coastal plain for years.  These things include mammoth and mastodon bones and teeth, and the occasional human artifact, or small load of human artifacts (Merwin 2010:44-46, for example).  

The apparently oldest deep water find came from near the outer edge of the submerged coastal plain.  Its submerged site overlooks an ancient valley of the Susquehanna River, and it was dredged up with a mastodon tooth and tusk fragment.  Known as the Cinmar biface, it may be as old as 23,000 years based on a radiocarbon date from the mastodon tusk, as well as its location on the submerged coastal plain now 100 km (62 miles) out in the Atlantic from the coast of Virginia (Stanford and Bradley 2012:100-103).  It is a remarkable find indicating that people were on the east coast of North America quite a long time ago.  And not just that, but they (or contacts they had inland) had obtained the rhyolite lithic material the biface was made out of from a stone source in western Maryland, far up the now submerged Susquehanna Valley and its upland tributaries.

Parenthetically, Cinmar is the name of the boat that found the artifact and mastodon remains.  Just so you know, the apparent great age of the Cinmar biface itself is difficult for some archaeologists to accept, and debate over details of its finding are part of a larger debate that may never end.  The points to consider here are: a. the distance (62 miles) out on the submerged coastal plain it reportedly was found, and b. sea level has risen 242 feet above the old surface it was dropped on when Pleistocene glaciers were melting fast.

Cinmar.  The proverbial extreme used to illustrate the mean.  From coastal areas between New Jersey and the Bay of Fundy, Native American artifacts of more recent age (but up to 10,000 or more years old) have been recovered from the sea floor or dredged spoil taken from the sea floor.  Often (but not always) the types of artifacts found are similar to those in terrestrial sites (Merwin 2010; Sanger 1988).  

My thoughts were cascading through data on the former occupation of land now under ocean water.  I thought of submerged sites under the North Sea, off the Florida panhandle…

Noticing I was still holding the newspaper, I skimmed it for important information.  Another quote from Professor Geisler:  “We are going to have more people on less land and sooner than we think”.  Whoa.  I had included this implication in my research.  Communities on the coastal plain and the drowning floodplains of the encroaching estuaries had to move inland into areas that were already populated.  Also, adjustments to changing coastal and shallow water environments had to be made to continue to ensure successful hunting-gathering-fishing economies. 

Geisler reported that Florida has begun planning for both coastal defense and exodus.  Six thousand, 8,000, 10,000 years ago, coastal defense was not a hunter-gatherers’ bailiwick, but exodus, that would have been the obvious solution.  As long as the coastal refugees could work it out with their inland neighbors.  I read down.  As Nearing began to mention the compound, world-wide problems of ocean water incursion in the present day, along with the issue of land already made unsuitable for refugee settlement by war, resource depletion, desertification, urban sprawl, etc., I began to think about the deep time precedents for human reaction to sea level rise.  

New communities moving into someone else’s homeland or even next to someone else’s homeland would have repercussions.  Exodus and refugee resettlement.  The alternative reactions of communities suddenly cheek-by-jowl in the broad geography used by hunter-gatherers include moving farther away if possible, or dealing with conflict and new modes of cooperation.  Archaeologists have often thought that the low population density of hunter-gatherers would have allowed plenty of room for people to move around.  I am not sure this is true, as evidence of larger early populations in New York accumulate.  Or at least it became less possible as populations were driven inland.   

Although hunter-gatherer conflicts go back a long way in some parts of the world, there is not a lot of evidence for conflict in the Northeastern U. S. archaeological record from about 5,000-10,000 years ago.  The evidence for cooperation, however, may be found in Northeastern community rituals from this time.  As I thought about this, I recalled the writing of the archaeologist Ken Sassaman (2010).  He considered the burial rituals of cultures he referred to as Northern Mortuary Traditions as the basis for diverse communities to coalesce, building new societies from disparate roots.  I recalled the evidence for these mortuary traditions, found in numerous publications.  One in particular, by archaeologist Brian Robinson (1996) is pretty comprehensive.  There was intense mortuary ritual along the coast and just inland from the coast, from the Canadian Maritimes to Massachusetts by 8,000 years ago, and probably beginning around 10,000 years ago.  These formed the basis for long traditions of mortuary ritual and special types of artifacts in coastal areas and along the lower reaches of New England rivers.  

Then suddenly, about 5,000-6,000 years ago, a complex of artifacts used in these rituals started to appear concentrated at sites in Ontario, New York and Vermont.  Burial rituals typically occurred at these sites also, although there are broad differences between the coastal and interior rituals.  Archaeologists working in the interior call this the group of ground and polished stone artifacts "Laurentian" due to an old assumption that their earliest use occurred in the region north of the St. Lawrence River (Ritchie 1969).

I put the newspaper down.  Facts had petered out at this point but the thought experiment flowing from Sassaman’s and Robinson’s perspectives continued.  Could this history of a select group of polished stone artifacts signify the importance of neighboring societies building functioning relationships?  Did this happen while inland migration may have packed many societies close together, requiring diplomacy and its material symbols and transactions?  Did this group of polished stone knives, gouges, plummets, spear-thrower weights and other artifacts (that are often a lot fancier than they need to be for utilitarian use) work in a social sense? Were they displayed and exchanged in interactions that built alliances and mutual obligations among communities, making it easier to live with closer neighbors or in larger, newly merged communities with diverse roots?  In the long history of sea-level rise, exodus, and in-migration in northeastern North America, do the changing contexts of Laurentian artifacts (and their deeper maritime traditions) hint at the ability of human communities to adjust?  The Big Picture is forming, and I’m wondering how the pieces fit together.   

References Cited
Boyle, Robert
  1979    The Hudson River:  A Natural and Unnatural History.  W.W. Norton, New

Dineen, Robert J.
1996    Holocene Environments in the Hudson Valley.  In A Golden Chronograph for Robert E. Funk, edited by Christopher Lindner and Edward V. Curtin, pp. 57-72.  Occasional Publications in Northeastern Anthropology, No. 15, Archaeological Services, Bethlehem, Connecticut. 

Eisenberg, Leonard
1982    A Preliminary Analysis of The Datum:  a Multicomponent Prehistoric Site near the Hudson River, Ulster County, New York.  Man in the Northeast 

Funk, Robert E. 
1976    Recent Contributions to Hudson Valley Prehistory.  New York State Museum Memoir 22, Albany.

1991 The Middle Archaic in New York.  Journal of Middle Atlantic Archaeology 

Gould, Stephen Jay
  1987 The Power of Narrative (Review of The Great Devonian Controversy by Martin J. S. Rudwick).  In An Urchin in the Storm:  Essays about Books and Ideas by Stephan Jay Gould, pp. 75-92.  W. W. Norton and Company, New York.  

McPhee, John
  1981    Basin and Range.  Farrar, Straus and Giroux, New York.

Merwin, Daria E.
2010    Submerged Evidence of Early Human Occupation in the New York Bight.  Ph.D. Dissertation, Department of Anthropology, State University of New York, Stony Brook.

Nearing, Brian
  2017    Global Crisis May Hit Home.  Albany Times Union, June 25, 2017.

Ritchie, William A.
  1969    The Archaeology of New York State, second edition.  Natural History Press, Garden City,    New York.

Robinson, Brian S.
1996    Archaic Period Burial Patterning in Northeastern North America.  The Review of Archaeology 17(1):33-44.

Sanger, David
  1988    Maritime Adaptations in the Gulf of Maine.  Archaeology of Eastern North America 16:81-99.

Sassaman, Kenneth E.
  2010    The Eastern Archaic, Historicized.  Altamira Press, Lanham, Maryland.

Stanford, Dennis J. and Bruce A. Bradley
  2012  Across Atlantic Ice:  The Origin of America’s Clovis Culture.  University of
    California Press, Berkeley.