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Rising Seas

Rising Seas: Past, Present, Future

Vivien Gornitz
Copyright Date: 2013
Pages: 360
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  • Book Info
    Rising Seas
    Book Description:

    The Earth's climate is already warming due to increased concentrations of human-produced greenhouse gases in the atmosphere, and the specter of rising sea level is one of global warming's most far-reaching threats. Sea level will keep rising long after greenhouse gas emissions have ceased, because of the delay in penetration of surface warming to the ocean depths and because of the slow dissipation of excess atmospheric carbon dioxide. Adopting a long perspective that interprets sea level changes both underway and expected in the near future, Vivien Gornitz completes a highly relevant and necessary study of an unprecedented age in Earth's history.

    Gornitz consults past climate archives to help better anticipate future developments and prepare for them more effectively. She focuses on several understudied historical events, including the Paleocene-Eocene Thermal Anomaly, the Messinian salinity crisis, the rapid filling of the Black Sea (which may have inspired the story of Noah's flood), and the Storrega submarine slide, an incident possibly connected to a sea level occurrence roughly 8,000 years old. By examining dramatic variations in past sea level and climate, Gornitz concretizes the potential consequences of rapid, human-induced warming. She builds historical precedent for coastal hazards associated with a higher ocean level, such as increased damage from storm surge flooding, even if storm characteristics remain unchanged. Citing the examples of Rotterdam, London, New York City, and other forward-looking urban centers that are effectively preparing for higher sea level, Gornitz also delineates the difficult economic and political choices of curbing carbon emissions while underscoring, through past geological analysis, the urgent need to do so.

    eISBN: 978-0-231-51920-5
    Subjects: Aquatic Sciences, Physics, Environmental Science

Table of Contents

  1. Front Matter
    (pp. i-iv)
  2. Table of Contents
    (pp. v-viii)
  3. Preface
    (pp. ix-xii)
    Vivien Gornitz
  4. Acknowledgments
    (pp. xiii-xvi)
  5. 1 The Ever-Changing Ocean
    (pp. 1-28)

    In the seemingly limitless extent of the ocean, the ancient sages envisioned a state of primeval formlessness out of which all life emerged. While the ancients had no concrete evidence for their intuitive insights, we now know from the geological record of sedimentary rocks that oceans have existed on Earth for at least 3.8 billion years, possibly more. Life has been present on Earth for almost as long. The first living cells most probably did originate in the ocean, although it has been debated whether this occurred in a shallow tidal pool or in the deep ocean at hydrothermal vents....

  6. 2 The Causes and Detection of Sea Level Change
    (pp. 29-60)

    An eroded cliff—the Orangeburg scarp—traverses much of the southeastern U.S. Atlantic Coastal Plain from North Carolina into Florida. The escarpment, a relict of ancient barrier islands and other shoreline features, formed at a time of much higher sea level, during the balmy mid- Pliocene epoch 3.5–3.0 million years ago.¹ Today, the base of the Orangeburg scarp stands about 85 meters (280 feet) above sea level, near where it crosses the North Carolina–South Carolina state line. When corrected for long-term regional uplift, mid-Pliocene sea level stood approximately 35 meters (115 feet) higher.² Other estimates vary between 10...

  7. 3 Piercing the Veil of Time: Sea Levels After the Dinosaurs
    (pp. 61-86)

    The world of the late Cretaceous period (80–65 million years ago) looked vastly different from the world of today. The Atlantic Ocean, which had begun to open up 180 million years ago, was still much narrower than now. A vast seaway covered much of the interior of North America. India hadn’t yet collided with Asia and the Tethys Sea separated Africa from Eurasia. The atmosphere held larger quantities of carbon dioxide, and sea level, by some estimates, was as much as 170 meters (560 feet) higher.¹ The world’s climate was still comfortably warm, although not quite the hothouse it...

  8. 4 When the Mammoths Roamed: Sea Levels During the Ice Ages
    (pp. 87-115)

    As recently as 20,000 years ago, continental-scale ice sheets blanketed most of Canada, the northern United States, and northern Europe. The future sites of New York City, Stockholm, Moscow, and other northern cities lay deeply buried under ice. The climate was bitter cold and dry. A polar desert and open tundra covered northern Europe beyond the ice sheet; permafrost extended south into central France. Southern Europe was mostly sparsely vegetated grassland or semiarid grassy shrubland.¹ Vast herds of large mammals, many of them now extinct, roamed the cold, windy, dusty, arid tundra steppes beyond the ice sheets. Our Paleolithic forebears...

  9. 5 The Great Ice Meltdown and Rising Seas
    (pp. 116-141)

    At the peak of the last ice age, the thick ice sheets that blanketed North America, northern Europe, and adjacent Russia, and the tall mountain ranges stored enough water to lower sea level by at least 120 meters (394 feet) relative to the present. Before the great flood, a land bridge connected Alaska and Siberia across the Bering Strait and a now-drowned subcontinent encompassed the seas between Malaysia, Indonesia, and Borneo. One could walk from China to Japan and across the English Channel! Continental shelves lay exposed to sunlight. Since the end of the last ice age, the invading seas...

  10. 6 The Modern Speedup of Sea Level Rise
    (pp. 142-165)

    The village of Gletsch in south-central Switzerland was once a way station on the old post coach route, which opened in 1866, over the Furka and St. Gotthard Passes across the Alps into Italy. A 19th-century topographic map hanging in the historic Hotel du Rhone lobby depicts the tongue of the glacier several hundred yards from the hotel. The proximity of the glacier to the hotel also appears on old drawings and postcards dating from about 1860 to 1870 (fig. 6.1). The Rhone Glacier, together with many other alpine glaciers, had advanced during the Little Ice Age, a cold period...

  11. 7 Sea Level Rise on a Warming Planet
    (pp. 166-187)

    In late April 2009, huge chunks of ice broke off a shelf on the western Antarctic Peninsula in Antarctica. Within days some 700 square kilometers (270 square miles) of ice had dropped off the Wilkins Ice Shelf, adding to the 330 square kilometers (127 square miles) of ice that crumbled within a week earlier that month, and 400 square kilometers (160 square miles) from the previous year (see fig. 6.2). Since the 1990s, the Wilkins Ice Shelf has lost 40 percent of its ice in a series of dramatic disintegrations, joining a growing list of ice shelves on the Antarctic...

  12. 8 Shorelines at Risk
    (pp. 188-220)

    Chesapeake Bay, the largest estuary in the United States, harbors extensive salt marshes, abundant waterfowl, and bountiful sea life. Its productive waters have furnished livelihoods for many generations of fishermen, and it also offers ample recreational opportunities today. The advancing sea began to inundate the Chesapeake Bay 9,000–8,000 years ago, drowning the ancestral Susquehanna River valley. As the submergence slowed, between 7,000 and 6,000 years ago, the estuary gradually assumed its modern shape. Few people realize that the sea is rising faster in Chesapeake Bay than elsewhere along the U.S. East Coast today. Seawater there is creeping upward at...

  13. 9 Coping with the Rising Waters
    (pp. 221-247)

    Loud, piercing siren blasts signal approaching “exceptionally high water” (acqua alta, in Italian) when the tide reaches or exceeds 140 centimeters (55 inches) above the 1897 reference datum. Movable raised plank walkways are rapidly installed across the plazas, shopkeepers and hotel owners place sandbags across their doorways, and people don hip-high boots (fig. 9.1). The high tide rises above the canals and sweeps across the Piazza San Marco and down the narrow streets and alleys of this historic, art-filled city. A tide of 140 centimeters or more submerges more than half the city. The most recent such event (at the...

  14. 10 Charting a Future Course
    (pp. 248-276)

    Over the eons, the ever-changing seas have danced to the daily rhythm of the tides, churned angrily in the midst of typhoons, and shape-shifted their basins to the languorous drift of tectonic plates. Time and again, the oceans have ebbed and swelled as the ice successively expanded and then slowly released its frigid grip across polar landmasses. What have we gleaned from the journey across the ages? This chapter explores the implications for the road ahead.

    Records of sea level change grow dimmer as time recedes into the past. Nonetheless, different strands of geological evidence point to a high sea...

  15. APPENDIX. Geologic Time Scale
    (pp. 277-278)
  16. Notes
    (pp. 279-300)
    (pp. 301-308)
  18. Bibliography
    (pp. 309-330)
  19. Index
    (pp. 331-344)