Central Italy Was 3-4°C Warmer Than Today About 10,000 to 12,000 Years Ago

In a new study, scientists use the new “ostracod-clumped isotope thermometer” to reconstruct a much warmer Late Pleistocene/Early Holocene Mediterranean climate.

Today’s average summer and winter temperatures are 22°C (21.4°C) and 8°C, respectively, at Central Italy’s Lake Trasimeno.

Around 11,000-12,000 years ago, when CO2 hovered in the 220-230 ppm range, summer temperatures averaged 25°C, sometimes rising to 27°C. This is at least 3°C warmer than today.

As CO2 concentrations rose into the Early Holocene (9,000 to 10,000 years ago), the ostacod-clumped isotope thermometer indicates summer temperatures at this location dipped to 23°C (22.5 to 23.2°C).

During this same period winter temperatures averaged 12°C (11.8°C), which is “4°C warmer than today.”

Image Source: Marchegiano et al., 2024