Two recently published studies confirm that the climate thousands of years ago was as warm or warmer than today’s – a fact disputed by some believers in the narrative of largely human-caused global warming. That was an era when CO2 levels were much lower than now, long before industrialization and SUVs.
One study demonstrates that the period known as the Roman Warming was the warmest in the last 2,000 years. The other study provides evidence that it was just as warm up to 6,000 years ago. Both studies reinforce the occurrence of an even warmer period immediately following the end of the last ice age 11,000 years ago, known as the Holocene Thermal Maximum.
The first study, undertaken by a group of Italian and Spanish researchers, reconstructed sea surface temperatures in the Mediterranean Sea over the past 5,300 years. Because temperature measurement using scientific thermometers goes back only to the 18th century, temperatures for earlier periods must be reconstructed from proxy data using indirect sources such as tree rings, ice cores, leaf fossils or boreholes.
This particular study utilized fossilized amoeba skeletons found in seabed sediments. The ratio of magnesium to calcium in the skeletons is a measure of the seawater temperature at the time the sediment was deposited; a timeline can be established by radiocarbon dating. The researchers focused on the central part of the Mediterranean Sea, specifically the Sicily Channel as indicated by the red arrow in the figure below. The samples came from a depth of 475 meters (1,550 feet).
Analysis of the data found that ancient sea surface temperatures in the Sicily Channel ranged from 16.4 degrees Celsius (61.5 degrees Fahrenheit) to 22.7 degrees Celsius (72.9 degrees Fahrenheit) over the period from 3300 BCE to July 2014. This is illustrated in the next figure, in which the dark blue dashed line represents the Sicily Channel raw temperature data and the thick dark blue solid line shows smoothed values. The other lines are Mediterranean temperatures reconstructed by other research groups.
With the exception of the Aegean data, the results all show distinct warming during the Roman period from 0 CE to 500 CE, when temperatures were about 2 degrees Celsius (3.6 degrees Fahrenheit) higher than the average for Sicily and western Mediterranean regions in later centuries, and much higher than present-day Sicilian temperatures. The high temperatures in the Aegean Sea result from its land-locked nature. During the 500 years of the Roman Warming, the Roman Empire flourished and reached its zenith. Subsequent cooling, seen in the figure above, led to the Empire’s collapse prior to the Medieval Warm Period, say the researchers.
The second study was conducted by archaeologists in Norway, who discovered a treasure trove of arrows, arrowheads, clothing and other artifacts, unearthed by receding ice in a mountainous region of the country. Because the artifacts would have been deposited when no ice covered the ground, and are only being exposed now due to global warming, temperatures must have been at least as high as today during the many periods when the artifacts were cast aside.
The last ice age hasn’t ended. The Quarternary began 2.5 million years ago, and is still going on. The Holocene is an interglacial that began almost 12,000 years ago, and now appears to be ending. All of human existence has occurred during an ice age, and all of human history has occurred during an interglacial in that ice age.
Just a general “tongue-in-cheek” comment regarding extrapolating from local data points:
According to the rules of climate science any local data can be used to in-fill for areas with no data…..
Example 1 Thermometer at Nuuk Airport in-filling for quite large parts of Greenland.
Ex 2: A thermometer in (or near) some random city in-filling for the surrounding country-side.
And yeah: A certain commenter with name starting with L got my goat.
The evidence keeps mounting up.
I’ve been seeing more studies recently going against the established narrative. Preparing for something, perhaps?
The Early Antique Little Ice Age started from around 350 AD, and that’s when the Western Roman Empire began its decline. What the first study confirms, is that the Mediterranean is warmer during grand solar minima, and that climate scientists have a habit of rewriting history to suit their back to front ideas.
Their labeling of the Late Early Antique Little Ice Age (LALIA) is also specious, the 700’s saw strong warming, and the late 700’s were the warmest part of the MWP for Northern European Summers (Esper et al, 2014). The positive NAO regime in the 700’s also drove a much colder North Atlantic and Greenland.
corr.. ‘Late Antique Little Ice Age’
It looks like Roman Empire collapse was caused (economically) by mud covering of many major seaports. A mud apocalypse? Greco-Roman civilization had economy based around large cities that had access to the sea. Anything else else, like regions in the mountains, was supplementary for the economy, rather than critical.
Today many of these former seaports are covered by mud, and the actual sea is kilometers away. Byzantium avoided collapse due to the manageable level of mud in its seaports.
Examples: Ephesus was silted around 3-rd centaury. Ostia (Rome’s seaport) was transformed to residential city, after the seashore moved out. The famous passage at Thermopylae which was narrow in ancient times is a wide plain now.
https://en.wikipedia.org/wiki/Deforestation_during_the_Roman_period
“Flooding/harbors and ports
Erosion accelerated up to twentyfold in the 3rd century, creating unusable marshlands, which spread diseases such as malaria. Flooding from runoff disrupted water supply to natural springs and rivers, but also increased siltation to coastal areas and harbours at river deltas. Rains washed away the unprotected earth and greatly altered coastlines, in some cases, pushing them many miles farther out to sea as in the case around the mouths of the Po River.[16] The washing away of topsoil and deposits of silt and gravel meant that harbors and ports needed to be moved, causing further burden upon the economy. Even in the city of Rome, floods covered the lower parts of the city and backed up the sewers. The first such flood was noted in 241 BC; records indicate increased flooding of the river from that time onward.[17] “