Guest Post from Allen McDonnell - "The Exundation of 1758"

 This article first appeared on Today in Alternate History. In this scenario, Allen W. McDonnell imagines the world mean sea level fell by a total of 400 feet two centuries earlier than in his guest post The Exundation of 1939.

In 1758, the world mean sea level fell by a total of 400 feet from where it had existed for the prior two millennia. This event, subsequently known as "the Exundation," would become the turning point of so-called Western Civilization.

THE WARNING
 

In his last days, Pope Benedict XIV personally warned about the vision he had received early in the month of February. In the normal course of events the Catholic nations tended to have most of their ships in port on Ash Wednesday so that the crews could more easily participate in the sacrament that marked the beginning of Lent. The pope warned the French, Portuguese and other predominantly Catholic countries like Poland via communication between himself and the heads of state of each power. Some took the warning to heart and ordered their navies and merchant fleet to be at sea at least at the horizon from any shore. Others like France had intended to ignore the warning but when they discovered the powerful Venetian fleet had set every movable ship out to sea, they scrambled to get their own ships to sea in order to be prepared for any sneak attack which might be in the offing.

Finally believing it was his Christian duty to warn all mankind, the pope issued a proclamation urging that all good Catholics and other Christians should have their ships at sea for the Lent because God was going to preform a miracle and that they would regret it deeply if their ships were in port. The Orthodox Czar of Russia openly scoffed at the proclamation and ordered all of his ships to make for port in defiance of the advice. The Lutheran powers of Northern Europe were torn, but when the French repented and sent their ships to sea, they followed to prevent a sneak attack bottling their ships up in port.

With Spain and Venice putting everything to sea, the other European powers almost unanimously decided that getting their fleets out to sea "just in case" was the wisest course of action. In Catholic Latin America, the Spanish and Portuguese colonies did not get the warning in time being so distant from Europe. This resulted in hundreds of merchant ships including the heavy Galleon designs still in use for cargo transport in the region and dozens of lighter faster naval vessels normally used for chasing down pirates and moving messages as quickly as possible all becoming stranded.

THE BEGINNING

In the North American British colonies, a fresh shipment of Redcoats had arrived late in 1757 and were preparing for the assault on Fort Louisbourg on Isle Royal which guarded the entrance to the Saint Lawrence River. These 1,500 men were mostly barracked on the troop ships which had ferried them across the Atlantic in the port of Halifax or for the officers and senior enlisted ranks quartered in civilian housing at the expense of the residents. No warning reached the colonists in North America for the same reason that it was lacking in Latin America. Over the great Ocean reaches, there was simply not time for even a fast courier ship to depart Europe and reach North America in the time between when the Pope issued his warning and the governments of France, the United Kingdom, and Spain reacted. It was later learned that a Spanish ship had been dispatched but ran aground on the Bahamas before reaching Saint Augustine in Spanish East Florida.

Much to the shock of the world at 6 PM in Jerusalem on February 8, 1758, the Great Exundation began. At first, nobody noticed because God is a loving Father, but at 7 PM world sea level had fallen five inches. By 6 AM the Mediterranean Sea level had fallen five feet. For the people who live inland, this could have been mistaken for the tide going out, but any experienced sailor in the Mediterranean knew that low tide was never more than a foot below mean sea level in the region because the small size of the water exchange at Gibraltar meant not that much water could move in and out of the basin in a tidal cycle. Exundation was even more obvious in Boston and Halifax where the ports routinely recorded tide levels and their records showed that as the regular tide went out sea levels on the edge of the harbor fell much further and faster than normal. Then when the tide came back in after twelve and a half hours, it peaked five feet below the expected value. If the Exundation continued for even a few days, ships in port would be stuck in the mud on rapidly drying land instead of floating in the sea. All the ships which had been at anchor were already firmly grounded by the time anyone realized action needed to be taken.

At London on the Thames river in the center of the ancient city, the change was even more obvious because the tidal range on the Thames was three times larger than that in North America. The low tide this far upstream from the North Sea had been three feet above mean sea level, and this had dropped to two feet below mean sea level while the highest tide expected that night had been 22 feet above mean sea level and had only risen to 17 feet. At this distance from the sea the river channel was nearly 60 feet deep to the bottom which was about 57 feet below mean sea level. The city of London was 115 feet above mean sea level the day before the Exundation began.

At 6 PM on Ash Wednesday in Jerusalem, world sea level had fallen ten feet from its previous average and it showed no sign of the Exundation stopping. Those captains who had been in port Ash Wednesday morning who still had vessels afloat had put to sea even if they were not really prepared for sailing wherever possible.

For the Russian navy, however, everyone had feared telling the Czar, but in Saint Petersburg he could see for himself it was too late for the Baltic fleet, the waters in the harbor were just too shallow at that end of the Gulf of Finland and the ships were all well stuck in the mud.

The Exundation continued hour by hour and day by day for forty nights and forty days. Finally at 6 PM on Palm Sunday, the Exundation ended as if it had never begun. World mean sea level had fallen a total of 400 feet from where it had existed for the prior two millennia. The parallels with the Great Flood of Noah were blatant and only a dedicated atheist could deny that they existed. An even greater parallel exists in that the inhabited coastal regions around the world find themselves in a steady drizzle of rain, gently rinsing everything for the entire 40 days but not slowing exundation in the slightest.

THE CONSEQUENCES EMERGE

London was now one more city in Continental Europe because the British Isles were now surrounded by land on all sides extending west of Ireland and north of Scotland even capturing the Shetland Islands. The Thames river now merged into the Rhine and the larger river meandered north on the east side of the hills which were once Dogger Bank halfway between the hills and the Jutland Peninsula until it reached the new Gulf of Skagerrak just south of Norway. The Baltic Sea had fallen greatly in level, with the passage between Copenhagen and Sweden now a dry valley leaving the city landlocked. However the remaining passage between the Baltic and the Skagerrak passed between the wider Jutland peninsula and the former island of Sjaelland now attached to Sweden from Copenhagen all the way to the new river valley that drained the shrunken Baltic. This left the nation of Denmark with much more land than before, but with a much longer border with Germany on the south and for the first time land connection with Sweden to the east and Great Britain to the west. Negotiation of the new borders was an immediate concern.

The Baltic and North seas had for all useful purposes ceased to exist and were now dry, and presumably valuable, land. As the sea level fall had been relatively gentle, in effect lowering the high tide on every cycle until the exposed shore had declined down 400 feet, the rainfall had rinsed the slight salt content of the new land away even as it was exposed.

Birds miraculously dropped seeds which had sprouted endless seeming acres of weeds and grasses on the newly exposed land and these were growing even as the many nations bickered over where the new borders should be drawn. Initially powers drew borders half way between themselves and whatever power occupied the dry land on the opposite side of the new dry seabed as a negotiation starting point.

This left the Denmark/Sweden border just east of the now landlocked Copenhagen in the valley which now sat where the sea passage had previously been. On the south this was effectively an extension of the old Germany/Denmark border using the same standards on both sides of the wider Jutland peninsula while in the west it was half way between old England and the same former peninsula which meant the enlarge Rhine now flowed through Denmark before the Thames merged into it to pass into old England. With the lower sea level the Thames had shrunken greatly in the area through London, no longer nearly 60 feet deep it was now closer to 20 in mid channel. There was just as much fresh water as before, but now the intrusion of sea water from below no longer buoyed it up to greater depth.

In Northwest America, an even greater change had taken place with the drying of the Bering Sea placing Alaska and Siberia in direct contact. On the Arctic side of Alaska the Chukchi Sea and Beaufort Sea were now dry land, albeit very cold dry land, and in New France (Canada) the Canadian Archipelago of arctic islands was now a peninsula bordering on the deep regions of the Arctic Ocean. The Baffin Passage and sea and much of Hudson's Bay had also drained away, leaving Greenland island now a peninsula of North America. Further south, the Saint Lawrence Estuary had shrunk and moved far east and passed just south of the British island colony of Newfoundland, which was now a peninsula jutting from the south east coast of New France (Labrador and Quebec).

The only ports in North America unaffected by the Exundation had been those on the Great Lakes, all of which were already well above sea level and isolated from the world's oceans by the Saint Lawrence river. Unfortunately these ports like Fort Ruoille on Lake Ontario and Montreal in the channel of the Saint Lawrence itself were under threat of attack by the Redcoats as the French and Indian war had been raging for several years by this time.

The great cities of the east coast now found themselves landlocked from dozens to hundreds of miles inland from the sea. Ships that had been under construction or in dry docks for major repairs were likewise now located dozens to hundreds of miles from the sea. Saint Augustine and Pensacola Florida were landlocked but the channel between Florida and the former Bahamas was still a sliver of water. The Gulf Coast of Florida was effectively now nearly 223 miles in average width where it had been 95 before exundation leaving the small port of Tampa and the administrative city of Pensacola far inland.

For every major nation outside of North America, the building of new ports on their new coastlines delayed shipping for many months. The war in North America disrupted this rebuilding effort because every port outside of the Great lakes had to be replaced but people were preoccupied with defensive works.

Philadelphia, where many ships had been built and repaired, scores of ships were now 400 feet above sea level and nearly a hundred miles as the crow flew from the newly formed coastline.

THE FUTURE BEGINS

The world was unable to quickly deal with the new crisis. Italy, for example, now has a massive new area of land because to the north half of the Adriatic Sea is now dry land creating a much longer border with Morlachia, Hungary. At the same time, Sicily is now attached by land, Sardinia has grown and merged with French Corsica, and the Barbary Pirates in Libya and Tunis are landlocked because the sea is hundreds of miles further north in the new dry land of North Africa. In the majority of the Balkans and eastern Mediterranean and Black Sea the Ottoman Empire was still the major power but things had changed a great deal. The Persian Gulf had drained down into a river mostly fed from the Tigris and Euphrates arising in Mesopotamia. The Sea of Azov had likewise drained to just the Don river valley, and the Crimean Peninsula was now merged into the greater north shoreline of the Black Sea. The rivers Dnieper and Danube were still major influx sources but the lower sea level meant the flow out through the Bosporus was much more rapid and harder to sail against.

The growing British Empire is badly mauled by the fact that much of the Royal Navy is now high and dry. The Straits of Gibraltar had been captured just 54 years earlier and had become a major naval fortification to make passage by enemies more difficult. Now the passage was narrower and far below the altitude of the existing fort making the guns there ineffective. To keep their influence, a new fort at the much lower level would need to be built and the heavy guns re-positioned, none of which would be quickly nor cheaply accomplished.

In addition to the changes in the Adriatic Sea the Aegean Sea that created the unique Greek culture on hundreds of islands is now dry land and the islands are mountains in that vast plain. In Central America, the land changes are just as remarkable. the Yucatan Peninsula of New Spain (Mexico) has doubled in size, Nicaragua has a new land area 30% larger than before and narrow Panama has grown nearly 50%. The relatively short trip across the isthmus to get to the Pacific is more than doubled and the fortified ports on each side are now high and dry with trapped ships inside the dry harbors.

On the bright side, a new archipelago has formed between Nicaragua and Jamaica, a scattering of islands that much resemble the Bahamas. Speaking of the Bahamas, much like Florida their area has effectively doubled, and, instead of dozens of islands separated by water, they are now a handful of much larger islands connecting groupings of the former scattered collection. Cuba has also expanded nearly 40% and only a narrow passage now separates it from the new Big Bahama island to its north east. Directly north a new island sits between Florida. Puerto Rico has grown to nearly double its former size and includes the Virgin islands now landlocked with it to the east and Mona island to the west leaving just a narrow passage between the expanded island and Hispaniola Island, which is the least changed gaining just a few percent of land around its steep coastlines. Most of the Caribbean islands have grown substantially, often merging into larger islands including several small islands together into larger landmasses. This is not a great cultural change until you approach northern South America where the islands of Trinidad and Tobago now find themselves part of the continent.

Further along the coast, Brazil and its northern neighbors outside of Venezuela gain modestly while to the south lightly explored Uruguay adds nearly 40% to its surface area while Argentina is massively expanded as well. This does present the difficulty of making Buenos Aries and Montevideo landlocked cities where yet again many ships are stranded in these fairly young colonial cities. This is the breadbasket of South America, and the expansion of the fertile prairies into what was the South Atlantic will eventually be of great benefit. Fortunately for the people of South America, very little that they import outside of slave labor is actually crucial to their economies. Between the great widening of Argentina to the east and the doubling in size of the disputed Falkland/Malvina Islands the British colony now finds itself physically attached to Argentina. However, little quickly changes because with so much of an increase in territory, the Spanish are much too busy to worry about the old claims in the short term. The not-yet-colonized islands of Tierra del Fuego are also greatly expanded, though other than increasing ranch land for the llama and sheep ranchers, this also has little immediate effect other than the closing of the Straits of Magellan.

The fertile Nile Delta has slumped outward into the new basin, and the river is cutting its way down through the accumulated silt to the new sea level, destroying the Egyptian breadbasket and washing away all the farmland for the last 50 miles of the Nile river valley. Ancient famine will be visited on Egypt once again, and this time the Muslim majority will be blaming the Christian minority because the Pope was the one who prophesied the warning.

For Africa, the greatest effects are in the northern coast as already discussed but a few notable exceptions do exist to the "not much changes" rule. The Canary, Madeira, and Azores islands off the north west coast generally find themselves gathered into much larger islands incorporating several or even many of the smaller pre-existing islands. In the furthest south, Africa gains a new fertile plain extending the continent as much as 80 miles from its old coastline and in the north east the Red Sea is shrunken with a narrow passage at the south end still connecting it to the Indian Ocean while in the north the entire Gulf of Suez is dry parched desert. Madagascar and the small island groups near it also benefit somewhat with the small island groups forming three larger islands much as took place off the opposite corner shore in the Atlantic.

Asia undergoes the greatest changes of all. Already the largest continent Asia now extends nearly 200 miles closer to the North Pole where Siberia has expanded northward. Along the east coast, massive new dry lands are formed south of Beringia incorporating Sakhalin and the four main Japanese islands in a long volcanic arc that attaches to South Korea and China at its southern extent. This turns the Sea of Japan into an inland sea with rivers winding out through the gaps on the north and south ends of Honshu. If the Exundation is permanent, this sea may become a new Black Sea with salty anoxic water in the lower basin covered by a brackish to nearly fresh surface layer fed by the rivers flowing down from Manchuria and the mountains surrounding the sea. The Yellow Sea and East China Sea are now broad expanses of freshly exundated land crossed by the ancient Chinese rivers. This land more than doubles the highly fertile Chinese lowlands which already support 300,000,000 rice farmers with their water-buffalo-drawn plows. Taiwan is an island no longer, now a mountainous plateau at the edge of this fertile territory and the Ryuku islands controlled by Japan further out to sea have gathered their clusters into new larger islands as has been seen with so many of the archipelago groups around the world.

While only the Japanese Honshu island is an island, these smaller groups remain detached from the Asian mainland. Further south the expansion of Asia has brought Hong Kong and Hainan islands into the continent and the draining of the Gulf of Tonkin, Gulf of Siam and the Java Sea have tripled the size of Indochina and merged the three main islands of the Dutch East Indies, Sumatra, Java and Borneo into Indochina. Even more surprising the additions to Borneo have captured the islands between that massive island and the Philippines forming all that formerly diverse territory into a massive new peninsula extending northeast from Borneo with the Sulu Sea a captive sea much in the guise of the Sea of Japan further north. A few of the eastern islands of the Dutch Indonesian colony escape incorporation into Asia like Celebes and Ceram, but the giant island of New Guinea is now incorporated into Australia , becoming the new northern end of the expanded island continent. In South Asia, the Bay of Bengal is slightly shrunken adding territory to Burma and the Indian subcontinent, which now incorporates the island of Ceylon as its southern tip. The Arabian Sea is slightly smaller and as already discussed the Persian Gulf is now a dusty desert plain between Arabia and Persia.

Australia is changed almost beyond recognition, now extending north past what used to be the island of New Guinea with the Gulf of Carpentaria and Arafua sea completely drained and the Timor Sea shrunken to leave a much narrower body of water between the continent and the island of Timor in the indies. In the south the coast goes further south greatly increasing the fertile region for European crops and Tasmania is no longer a lone island but now part of continental main mass.

New Zealand is no longer two large islands in the company of dozens of smaller ones; instead, it is one very large island extending slightly further north, east and west and considerably further south. The associated islands all progressed through the conglomeration effects with the two main Chatham islands becoming one larger island and the Auckland islands forming one larger island.

Across the broad Pacific, this same scenario is played out many times with small islands and nearby islets being gathered together by the Exundation effect to form one or more much larger islands. In Hawaii the famous Pearl Harbor is left high and dry and the island of Molokai is nearly doubled in size by the exposure of its western half known as the Penguin Bank to fishermen. As a general rule, however, the Hawaiian Island chain have very steep slopes below the water line so the total additional territory in general only extends outward a handful of miles. With the exception of Molokai, none of the islands is remarkably enlarged or gathered together with recognized islands to form a new larger island.

Last but not least, in the little-explored continent of Antarctica, every ice shelf floating on the edges of the continent become hard grounded ice sheets indistinguishable from the vast dome of ice covering the interior. Because the Exundation took place late in Antarctic summer and early fall, the loosely floating sea ice was at its minimum extent, but what remained was mostly grounded on the now exposed Antarctic continental shelf covering the freshly exposed mud in a meter of stranded sea ice. As a result as the fall progressed and winter set in fresh snow falling on the newly exposed shelf fell onto this freshwater ice and started easily accumulating in place.

Because the new land has been under a rainy drizzle for the entire Exundation, it is very wet and impassable on the night of Palm Sunday; however, March 19, 1758, dawns with bright sunshine and starts rapidly drying up the exundated land to more normal condition.

The UK was now also face to face with the fact that the Royal Navy was no longer a shield between itself and Continental Europe. From a point just east of Hurd's Canyon all the way to the Norwegian Sea curving around east and north from that point, the UK was now firmly attached to Europe by land. While the UK had some of the very largest territorial gains in Europe as a result, for the first time in its two millennia history was vulnerable to land armies. France immediately takes advantage of these new facts to attack Great Britain directly in what evolves into a new Fifty Years War.

On the spiritual front, the Catholic faith is strongly boosted, and many Protestant Christians and not a small number of non-Christians convert to Catholicism because they believe the Pope really is the conduit from God to Man on earth. This even leads to a large number of Muslims in the hardest hit areas converting, though it also hardens the resolve of the most devout Islamists that this is all the work of Shaitan to mislead the masses away from the True Faith in Allah. Most of the Judaeo-Christian-Islamist faithful learn the story of Noah's flood from early childhood, and the only thing that places special emphasis on the Papacy and Catholic division is the Pope's public warning to all Christians. This leaves more than enough wiggle room for the truly devout members of other sects within the overall belief in Jehovah/God/Allah of the Old Testament to remain within their own belief but for those doubters who want miraculous proof the Exundation is plainly what they were seeking on some level.

In Latin America, it sinks in to the Spanish and Portuguese colonists that they are effectively cut off from exporting mineral wealth, sugar and tobacco to markets in Europe. They also realize they will no longer have a steady supply of African slave laborers flowing into their lands. A struggle to adapt to a more self-sufficient culture ensues.

In North America, the opportunistic Baron Jeffery Amherst sees the Exundation as a clear miracle separating him from Great Britain. At first he carries through the grand strategy drawing on colonial population to increase his military strength and using his advantages and skill to overwhelm the French fortifications, effectively ending the war in 1761. By this time, small boats have been built in the new harbors of the east coast and have discovered that the United Kingdom and France are engaged in a vast war and both sides have completely forgotten their colonies in the face of total war between themselves. Amherst surprises the colonials by declaring himself King of America as the most senior official of the now-absent British government. To solidify his throne, he creates his own American nobility, giving titles of Marquis, Viscount, Earl, and Baron to leading citizens born in the colonies almost all of whom are from the wealthiest families. A few exceptional colonial officers like Baron George Washington of limited wealth but military prowess are added into the new nobility by virtue of their usefulness to the new Royal Family. With military skill and an American Parliament meeting in Philadelphia which he selected as his capital in imitation of London. The city is now far from the coast, but the Delaware River meanders down the 400 foot slope to the new sea shore and ensures fresh water will always be available to the city, and, with a lot of work, the ships trapped in dock can be moved to the river and gotten back out to the Atlantic to serve as the core of a new Navy.

Jeffery I is a dedicated expansionist, and one of his favorite methods of negotiating with First Peoples on the edge of his nation is to gift them with blankets carefully selected from the sick beds of persons infected with smallpox. After the disease sweeps through the settlements so treated, it is a simple matter for his standing army of ruthless redcoats to secure the new territory while the nobility has the area surveyed and distributed for development. At the same time, all the newly exposed continental shelf is quickly converted into pasture lands and agricultural developments because the fast-growing seeds dropped by the birds during the Exundation are no obstacle to the plow. Surveyors mark out areas reserved as woodlots and teams of foresters bring in the desired tree species, but it will be a decade or several decades before the newly planted trees are worth harvesting for any useful purpose. Plowing the newly defined fields is mostly a case of scouring the soil for field stones and then working the new land with an ox drawn plow for planting. The short sharp brutal war on New France delays these actions for two years, but by then the sod has completely stabilized the new lands and the area is ripe for development.

AUTHOR'S NOTE

After talking it over with Steve a few weeks ago, I have written up what I think may have happened if the proposed Exundation of the continental shelf had taken place 150 years after the founding of the Jamestown colony in Virginia. I hope you all enjoyed it. By this point, after the founding the English were in firm control of the coast from Spanish Florida all the way to the tip of Nova Scotia with Acadia in what is today New Brunswick being the only real exception and the French colonists there were few and far between. Climate-wise this is still "The Little Ice Age," and a modern resident of Philadelphia or Wilmington would be shocked by the cold winters and cooler summers compared to 2021. Benjamin Franklin is a successful inventor and printer in Philadelphia in his early 50's, and I see him being an early and eager convert to an independent American Monarchy. With all the wars erupting in Europe due to the Exundation, the colonial period is at the very least going to suffer a long interruption, and, in those places where the European colonists can stay in control and prosper, the old home countries will face stiff competition if they try and resume their empires once they have settled things in Europe. British North America is particularly well positioned for this breaking off of contact as the population is already undergoing rapid growth and an increasing majority of leading citizens are born Americans, not immigrants. Historically less than a century after this date the USA+Canada will have a population larger than Great Britain. In large part, this is because North America east of the Mississippi is about five times the size of the island of Great Britain, and European diseases have weakened and depopulated the natives to the point the newly born palefaces can move into these lightly populated frontiers and convert them into European-style landscapes with small farms and ranches interspersed with woodlots.