Sustained North Atlantic warming drove anomalously intense MIS 11c interglacial

Area of Science:

• Paleoclimatology
• Climate Science
• Geochronology

Background:

• Marine Isotope Stage (MIS) 11c interglacial and its glacial termination exhibit a strong climate response to weak insolation forcing.
• Radiometric age control has been lacking, hindering the assessment of the insolation-climate relationship during this period.

Purpose of the Study:

• To present new radiometric age control for the MIS 11c period.
• To assess the insolation-climate relationship during MIS 11c.
• To compare paleoclimate records from Italy and the North Atlantic region.

Main Methods:

• Uranium-thorium (²³⁰Th) dating of speleothems from northern Italy.
• Comparison with existing paleoclimate records from the North Atlantic region.

Main Results:

• Interglacial conditions began in subtropical to middle latitudes at 423.1 ± 1.3 thousand years before present (kyr BP) during a weak insolation maximum.
• Northern high latitudes remained glaciated, with sea level approximately 40 meters below present.
• Peak interglacial conditions, with sea level 6-13 meters above present, were reached globally 14.5 ± 2.8 kyr after the subtropical onset, despite weak insolation forcing.

Conclusions:

• The intense climate response during MIS 11c is attributed to a prolonged (~15 kyr) episode of significant poleward heat flux transport.
• This finding provides critical insights into the complex interplay between insolation forcing and Earth's climate system during interglacial periods.