Guest post by David Middleton
From The New York Times…
FirstAmerican ‘Climate Refugees’
By CORAL DAVENPORT and CAMPBELL ROBERTSON
ISLE DE JEAN CHARLES, La. — Each morning at 3:30, when Joann Bourg leaves the mildewed and rusted house that her parents built on her grandfather’s property, she worries that the bridge connecting this spit of waterlogged land to Louisiana’s terra firma will again be flooded and she will miss another day’s work.
Ms. Bourg, a custodian at a sporting goods store on the mainland, lives with her two sisters, 82-year-old mother, son and niece on land where her ancestors, members of the Native American tribes of southeastern Louisiana, have lived for generations. That earth is now dying, drowning in salt and sinking into the sea, and she is ready to leave.
With a first-of-its-kind “climate resilience” grant to resettle the island’s native residents, Washington is ready to help.
“Yes, this is our grandpa’s land,” Ms. Bourg said. “But it’s going under one way or another.”
In January, the Department of Housing and Urban Development announced grants totaling $1 billion in 13 states to help communities adapt to climate change, by building stronger levees, dams and drainage systems.
One of those grants, $48 million for Isle de Jean Charles, is something new: the first allocation of federal tax dollars to move an entire community struggling with the impacts of climate change. The divisions the effort has exposed and the logistical and moral dilemmas it has presented point up in microcosm the massive problems the world could face in the coming decades as it confronts a new category of displaced people who have become known as climate refugees.
“We’re going to lose all our heritage, all our culture,” lamented Chief Albert Naquin of the Biloxi-Chitimacha-Choctaw, the tribe to which most Isle de Jean Charles residents belong. “It’s all going to be history.”
My first question is: How in the Hell did Chief Albert Naquin’s ancestors cope with the Holocene transgression without welfare payments from the Department of Housing and Urban Development?
Now, I know that the Biloxi-Chitimacha-Choctaw didn’t migrate north from what is now the seafloor of the Gulf of Mexico during the Holocene transgression (Andrew Jackson put them on Isle de Jean Charles); but I do know that a lot of paleo-Indians did take that trip. There are numerous archaeological sites in the Gulf, where paleo-Indian settlements existed. When locating wells, platforms and other useful infrastructure on the shelf, we actually have to avoid anything that looks like submerged Pleistocene stream channels because the paleo-Indians might have left a few arrowheads along the banks of those paleo-rivers. I guess during the next glacial maximum, future archaeologists will hike out there and recover these priceless “archaeological resources.”
Note to nitpickers: Some of the above was intentionally sarcastic.
Getting back to the subject, how is it that the Amerindians of the Pleistocene were able to adapt to somewhat more severe climate change without government assistance?
The Prehistory of the Texas Coastal Zone: 10,000 Years of Changing Environment and Culture
The story of prehistoric human culture on the Texas coast is about how hunting and gathering (non-farming) populations adapted to the opportunities and constraints of their shoreline and nearby prairie environments using limited technology bolstered by first-hand knowledge about the location and seasonal availability of important subsistence resources.
Dominant Environmental Factors
The coastline as we see it today is, from a geologic perspective, a very recent phenomenon that dates back only about 3,000 years. In fact, prior to around 8,000 B.C., the area of the modern shoreline was high and dry, with the Gulf coast far to the east of its present position. This is because, in earlier millennia, global sea level was as much as 100 meters (over 300 feet) lower, with much of the world’s water supply “locked” in vast continental ice sheets and montane glaciers that were far more extensive than those of modern times. This era, the Pleistocene (or, in common parlance, the “Ice Age”) had markedly lower global temperatures than those of historical times. The final cold phase of the Pleistocene was around 20,000 years ago, after which rising global temperatures caused the continental ice sheets and mountain glaciers to begin a gradual melting process, with the result that sea level began to rise rapidly over the next 10,000 years.
As sea level rose, shorelines around the world moved progressively father[sic] inland. By 8,000 B.C. the sea had inundated major river valleys along the Texas coast. The flooding of the valleys of major streams, such as the Trinity, Lavaca, Guadalupe, Aransas, and Nueces Rivers created the earliest forms of our modern coastal bays (respectively, Galveston, Matagorda, San Antonio, Copano, and Corpus Christi Bays). The same presumably occurred at the mouths of the Brazos and Rio Grande Rivers, but the heavy sediment loads (clay, silt and sand) carried by these major rivers have since filled in whatever early bays were created by sea level rise.
After this time, sea level continued to rise until relatively recently, but at a slower rate. Many geologists have suggested that rising sea level was not gradual or continuous, but rather that it was intermittent, with periods of rise interrupted by intervals of stable sea level. By around 3,000 years ago (1,000 B.C.), sea level had reached its modern position and has since then been basically stable (though probably with some minor fluctuations). With sea level at a still stand, ongoing wave action and longshore drift deposited sand and shell hash parallel to the mainland, forming the modern chain of barrier islands (Padre, Mustang, San Jose, and Matagorda Islands along the middle and lower Texas coast and Galveston Island and Bolivar Peninsula along the upper Texas coast). For additional diagrams charting these environmental changes, see Changing Sea Level and the Evolution of the Modern Coastal Environment.
Archeological research on the upper and middle portions of the Texas coast has shown that prehistoric human occupation of the shoreline varied markedly in its intensity over that last 10,000 years, the geologic epoch known as the Holocene. Based on the information we have now, the first period of occupation by early people was between ca. 8,200 and 6,800 years ago, after which occupation was relatively sparse. Then there was a major period of shoreline occupation between 6,000 and 4,000 years ago. This was again broken by a one-thousand-year hiatus, during which evidence for occupation is very limited. Starting around 3,000 years ago, or ca. 1,000 B.C., there is again abundant evidence for major occupation, during which time fishing became an increasingly important part of the subsistence economy of the human inhabitants.
Based on some of the geological estimates of the pattern of sea level rise during the Holocene Epoch, it appears that the three major periods of human occupation and resource extraction along the bayshores corresponded with times of relatively stable sea level. This makes good sense from an ecological perspective, since when sea level was at a still stand, ongoing sedimentation of bay bottoms (as rivers dropped their sediment loads into the bays) created extensive shoreline shallows that supported extensive salt marshes and grass flats. Also, the shallow water had high rates of photosynthesis that, combined with the high plant biomass from the marshes and grass flats, produced the organic nutrients needed to sustain high aquatic biomass and a rich food chain comprised of salt-tolerant plant communities, crustaceans, mollusks and fish. These environments offered prehistoric hunting and gathering peoples a secure subsistence base, which resulted in their establishing camps along bayshores from which they could procure a rich harvest of shellfish and fish. Such encampments are in evidence today as the many archeological shell middens that dot the shores of the bays and lagoons of the Texas coast.
In contrast, when sea level was rising more or less rapidly (between 6800-6,000 B.P. and 4,000-3,000 B.P.), the extensive shoreline shallows became more deeply submerged, thus reducing photosynthesis and depressing overall biotic productivity, with the result that the bayshores became far less attractive to prehistoric people. Thus we see a marked reduction in archeological evidence for these periods along the bay shorelines.
Clearly, America’s first actual climate refugees weren’t welfare migrants, dependent on government assistance.
A Little Geology
While Isle de Jean Charles isn’t a barrier island, it has been disappearing since the 1930’s for pretty much the same reason as Louisiana’s barrier islands…
As the land disappears, an Indian tribe plans to abandon its ancestral Louisiana home
For at least 170 years, Isle de Jean Charles — a narrow ridge of land lying between Bayou Terrebonne and Bayou Pointe-aux-Chene in southeastern Louisiana’s Terrebonne Parish — has been home to members of the Biloxi-Chitimacha tribe, native people related to the Choctaw and part of a larger confederation of Muskogees.
But the tribe’s history is about to take a dramatic turn due to climate change.
Land loss has long been a problem facing Louisiana, which has seen 1,900 square miles of land vanish since the 1930s and which continues to lose as many as 40 square miles each year to the Gulf of Mexico. With every bit of land swallowed by the sea the loss rate speeds up, since the coastal wetlands and barrier islands act as storm buffers. If action is not taken to slow the current loss rate, the Louisiana shoreline is expected to move inland as much as 33 miles by the year 2040.
Factors behind Louisiana’s escalating loss of coastal land include natural subsidence as well as the construction of flood-protection levees, which block the natural deposition of land-building sediment. Meanwhile, the dredging of access canals by the state’s offshore oil industry lets in salt water that in turn kills marsh vegetation, further worsening erosion. At the same time, man-made global warming is increasing sea levels through thermal expansion of water and melting continental ice sheets.
Setting aside the obligatory reference to sea level rise for a moment, let’s look at the geology…
Louisiana Barrier Islands: A Vanishing Resource
USGS Fact Sheet
“The barrier islands of Louisiana are eroding at an extreme rate. In places up to 100 feet of shoreline are disappearing every year. Though it has long been assumed that this erosion was due to the area’s rapid rate of relative sea level rise, recent studies by the U.S. Geological Survey show that other coastal processes, such as the longshore redistribution of sediments, are responsible for this erosion.”
– Dr. Jeffrey H. List, U.S. Geological Survey
The environmental consequences of coastal erosion in Louisiana may be severe.
Louisiana’s barrier islands are eroding so quickly that according to some estimates they will disappear by the end of this century. Although there is little human habitation on these islands, their erosion may have a severe impact on the environment landward of the barriers. As the islands disintegrate, the vast system of sheltered wetlands along Louisiana’s delta plain are exposed to increasingly open Gulf conditions. Through the processes of increasing wave attack, salinity intrusion, storm surge, tidal range, and sediment transport, removal of the barrier islands may significantly accelerate deterioration of wetlands that have already experienced the greatest areal losses in the U.S. Because these wetlands are nurseries for many species of fish and shellfish, the loss of the barrier islands and the accelerated loss of the protected wetlands may have a profound impact in the billion dollar per year fishing industry supported by Louisiana’s fragile coastal environment.
U.S. Geological Survey (USGS) studies collect information critical for improved predictions of long-term erosion rates.
The USGS, in cooperation with Louisiana State University, documented the long-term historical record of bathymetric and shoreline change along the Louisiana coast. For example, historical data over the past 100 years indicate that the shoreline at Bayou Lafourche has eroded back about 3 kilometers. The pattern of long-term, large-scale bathymetric change is key information in determining the processes of barrier island evolution and in formulating predictions of future changes. USGS scientists have assembled bathymetric surveys from data from the 1880’s, the 1930’s, and the late 1980’s, and are in the process of assembling a similar survey in 1993 following the passage of Hurricane Andrew. This base of information will be used to evaluate the contribution of catastrophic events to the long-term evolution of this coastal area.
Recent USGS work indicates that rapid relative sea-level rise is not the primary cause of erosion of the barrier islands.
Until this USGS study was undertaken, environmental managers thought that the principal cause of barrier island erosion was rising sea level. Now, we know that both the longshore movement of sediment and the general absence of sand-sized sediment is the principal cause of the islands’ instability. The sediments underlying coastal Louisiana are made up mostly of silts and muds which do not contribute to the building of beaches, dunes, and spits—geomorphic features associated with healthy barrier islands. In addition, long-shore currents redistribute the available sand from headland areas to embayments, depriving shorelines of much needed sand.
“Recent USGS work indicates that rapid relative sea-level rise is not the primary cause of erosion of the barrier islands.”
All of the news reports about “Resettling the
First American ‘Climate Refugees’” exclusively blame AGW and rapid sea level rise for the plight of the Biloxi-Chitimacha-Choctaw people of Isle de Jean Charles, despite the fact that the real causes of their dilemma are Andrew Jackson and geology. Sea level rise in the vicinity of Isle de Jean Charles has been rather unspectacular…
So, let’s hope America’s first geology refugees find a nice, new home, free from geological and geophysical hazards… Maybe the $48 million in welfare can be issued in new $20 bills…