International researchers have found proof that the Mediterranean Sea was 3.6 degrees Fahrenheit (2 degrees Celsius) hotter during the time of the Ro
International researchers have found proof that the Mediterranean Sea was 3.6 degrees Fahrenheit (2 degrees Celsius) hotter during the time of the Roman Empire , from 1 to 500 AD, the warmest it has been over the past two millennia. The researchers claim that their investigation can show the relationship between climate change and important social and cultural changes, including the rise and fall of empires.
A multidisciplinary team of Spanish and Italians researchers were part of a project for “the Intergovernmental Panel on Climate Change (IPCC) to assess the impact of historically warmer conditions between 2.7°F and 3.6°F (1.5°C to 2°C),” reports the Daily Mail . It is very challenging to retrieve information about past temperatures of the sea.
According to the Daily Mail , the experts believe that “the study of the fossil archives remains the only valid tool to reconstruct past environmental and climatic changes as far back as 2,000 years ago.” Due to the fact that it is enclosed, the Mediterranean Sea is more likely to be impacted by global climate change. “The sea occupies a ‘transitional zone’, combining the arid zone of the subtropical high and humid north-westerly air flows,” explains the Daily Mail .
The research team retrieved planktonic organisms from the sea floor off the coast of Sicily. The map shows the location of the sample (red triangle) and the location of marine records used for comparison (red circles). ( Margaritelli, G. et. al. / Scientific Reports )
Planktonic Organisms Hold Information About Past Sea Water Temperatures
The team recorded ratios of magnesium to calcite in planktonic singled cell organisms, called foraminifera Globigerinoides ruber, and this provided much-needed data. In 2014 the RV CNR-Urania research vessel was able to retrieve a skeletonized Globigerinoide ruber from the sea floor in the Sicily Channel, at a depth of 1500 feet (490 m). Professor Isabel Cacho, of the University of Barcelona, is quoted by Mirage News as saying that a chemical analysis of the “carbonated skeleton allows us to reconstruct the evolution of the temperature of the surface water mass over time.” This is because the organism only lives in warm marine habitats.
The data suggested that between 2000 and 1500 years ago the Mediterranean Sea temperatures were warmer than at any time since. It is believed that the sea was warmer because of increased solar activity. It was almost certainly not a result of global warming caused by greenhouse gases, such as carbon emissions. “For the first time, we can state the Roman period was the warmest period of the last 2,000 years, and these conditions lasted for 500 years,” explains Cacho in Mirage News . The study was correlated with data from other samples taken from other locations in the Mediterranean Sea, which confirmed their hypothesis.
The data collected from the Sicily Channel was compared to data from other locations in the Mediterranean Sea, and superimposed on a graph showing the main historic periods discussed in the study. ( Margaritelli, G. et. al. / Scientific Reports )
Cooling Sea Water Linked to Fall of Roman Republic
The Mediterranean was cool and humid until 100 BC, in what is known as the sub-Atlantic phase. The sea began to cool markedly after 50 BC. This has been linked to the eruption of Mount Okmok, off the coast of Alaska, that threw ash into the atmosphere leading to the cooling of the earth.
This cooling may be linked to the collapse of the Roman Republic and the rise of the new imperial system in Rome. Augustus established the Roman Empire in 27 BC, after his victory at Actium. This was to endure for 500 years, during which time the Roman Empire dominated the Mediterranean world. The team wrote in Scientific Reports that “this climate phase corresponds to the so-called ‘Roman Climatic Optimum’,” characterized by mild and wet weather.
During his reign as emperor of the Roman Empire, from 27 BC until his death in 14 AD, Augustus increased the size of the empire substantially. ( Abraham de Bruyn / CC0 )
Warm Mediterranean Sea Temperatures Associated With Golden Age of Rome
The researchers believe that the Roman Climatic Optimum phase coincides with “the development of the expansion of the Roman Empire ,” explains Mirage News . The warm period has also been associated with the Golden Age of Rome, both culturally and economically.
Evidence for the warming of the Mediterranean during this period is also supported by separate studies from the Atlantic. The warm period may have helped to boost the Empire’s agricultural production , which was critical for the prosperity and stability of pre-industrial societies and even increased their military capabilities.
After the fall of the western Roman Empire, “a general cooling trend developed in the region with several minor oscillations in temperature,” clarifies the Daily Mail . This could have contributed to the decline of classical civilization after 500 AD. In Scientific Reports , the researchers write that the cooling was “also associated with socio-cultural changes in the central Mediterranean region.” The climate became drier and this meant that agriculture was not as productive and could not sustain cities in particular.
Destruction, by the English painter Thomas Cole, was painted to show the fall of the Roman Empire. ( Public domain )
Can Climate Change Cause the Rise and Fall of Empires?
Combined with other research studies, this study has helped to demonstrate a potential link between climate change and the rise and fall of empires and civilizations . Quoted in the Daily Mail , those involved in the study explain that their work “offers ‘critical information’ to identify past interactions between climate changes and evolution of human societies and ‘their adaptive strategies’.” Moreover, their work can also help to understand the history of other empires that once thrived in the Mediterranean region, and the effects of changes in climatic temperatures.
Top image: Mediterranean Sea. Credit: Sergii Figurnyi / Adobe Stock
By Ed Whelan