The Great Flood(s) - Real Possibilities of Sea Level Rise?

When dealing with the issue of sea-level rise, why not start with the story of Noah's Ark. Whether a believer or not, as science and theology now both claim to provide a potential answer.

Of course we all know the biblical tale of Noah's Ark, God's condemnation and punishment on his flawed people came by the means of a great flood. Noah received a message from God telling him to build a great Ark in order to save a select few people and all the animals in their gender pairs so being able to start life afresh once the waters subsided.

Now scientific discovery has provided an alternative for the tale, as in 1999 a survey of the Black Sea continental shelf off the north central Turkish seaport of Sinop using sonar, remotely operated vehicles, and a series of dredge lowerings located, inspected and sampled an exposed paleoshoreline (past shoreline) at a depth of 155 m. In these depths Ballard et.al discovered evidence of a people who perished in a great flood of the Black Sea. Radiocarbon dating of mollusk shells collected from this ancient beach revealed that the marine flooding of the Black Sea took place between 7460 and 6820 years before present, changing it from a lacustrine (lake) to marine (sea) environment. Evidence for the people there comes ancient mud and wooden house had collapsed, and they found tools of highly polished stone, together with fragments of ceramics.

The geological evidence suggests the rising Mediterranean sea pushed a channel through what is now the Bosphorus, also known as the Istanbul Straits, and then seawater poured in at about 200 times the volume of Niagara Falls. The Black Sea would have widened at the rate of a mile a day, submerging the original shoreline under hundreds of feet of salty water. In total nearly 100,000 square miles were inundated. 

Ballard does not claim to have found the landscape of Noah but what he does know is that there has been a major flood and that people were living here when it happened. The jump to Noah comes from the timeframe and location leading some to believe this to be the source of the biblical tale, e.g. Noah's Ark came to rest in Turkey.

Regional map of the Black Sea and the surrounding landmass, including the location of mountainous terrain and locator map. The 155 m contour is shown as well as the 1999 study area (Ballard et. al. 2000).

So now onto modern day and again to use the classic symbol with flooding today, one has to look at Bangladesh.  Bangladesh is very prone to flooding due to its location at the confluence of the Ganges, Brahmaputra and Meghna (GBM) rivers and because of the hydro-meteorological and topographical characteristics of the basins in which it is situated, i.e 60% of the sea level is 6m below or more below sea level (USAID, 1988)! On average, annual floods inundate 20.5 per cent area of the country and this can reach as high as about 70 per cent during an extreme flood event. The societal exposure to such risks is further enhanced by Bangladesh’s very high population and population density. These floods cause serious damage to the economy of Bangladesh, a country with a low per capita income. Global warming caused by the enhanced greenhouse effect is likely to have significant effects on the hydrology and water resources of the GBM basins and might ultimately lead to more serious floods in Bangladesh (Mirza, 2002).

References

Ballard, R.D., Coleman, D.F. and Rosenburg, G. (2000) Further evidence of abrupt Holocene drowning of the Black Sea shelf. Marine Geology, Volume 173, Issues 1–4, 15 March 2001, Page 143.

Mirza, M.M.Q (2002) Global warming and changes in the probability of occurrence of floods in Bangladesh and implications. Global Environmental Change, volume 12, issue 2, pages 127-138.

USAID, 1988. OFDA Annual Report. Office of the US Disaster Assistance Agency for International Development, Washington DC, pp. 110–122.