Roman Fish Tanks and Global Sea Level Rise

Like a lot of people who studied geology and paleoclimatology in the 1970-80's, I was taught that sea level had been rising since the end of the Pleistocene and the melting of the glaciers that covered so much of the land mass of the Northern Hemisphere. On field trips to the eastern shores of North America I saw abundant evidence of how sea level had risen over the last 15-12,000 years in the form of submerged human settlements and previously subaerially exposed geological features.

While nothing has been discovered to refute this model of what might be called "natural" or non-anthropogenic rise in sea level, there appears to be evidence that up to 2000 years ago, the rate at which sea level rose was much slower. In other words, at 2000 years BP (Before Present) sea level began to rise faster. It is presumed that the increase in the rate of sea level rise is a function of an increase it the growth of human populations and the resultant increase in deforestation and output of carbon dioxide from the burning of wood and coal, coupled with an increase in methane and other greenhouse gases associated with human activity.

Ok, so why am I writing about changes in sea level in a blog that is putatively devoted to the subject of food and cooking? Well, it turns out that some of the evidence for the acceleration of the rise in sea level over the last 2000 years comes from an examination of the fish tanks that ancient Romans used to impound fish destined for the dinner table.

For a more complete explanation of the nexus of rising sea level, Roman fish cookery, deforestation, and anthropogenic out-gassing you can read this or watch the video or do both.