Intertropical convergence zone variability in the Neotropics during the Common Era

Area of Science:

• Paleoclimatology
• Neotropical Climate Dynamics
• Hydroclimate Variability

Background:

• Neotropical hydroclimate changes during the Little Ice Age have been linked to shifts in the Intertropical Convergence Zone (ITCZ).
• Previous research suggests various modes of ITCZ variability, necessitating further investigation.
• Understanding past ITCZ behavior is crucial for predicting future climate impacts in sensitive regions.

Purpose of the Study:

• To reconstruct ITCZ variability throughout the Common Era using paleoclimate proxy data.
• To test the hypothesis that ITCZ behavior is linked to global temperature fluctuations.
• To assess the implications of ITCZ shifts for arid and variable conditions at its margins.

Main Methods:

• Analysis of seasonally resolved stalagmite rainfall proxy data from southern Belize, near the ITCZ's northern limit.
• Integration of paleoclimate records from across the Neotropics and subtropics.
• Comparison of proxy data with climate model simulations of ITCZ behavior.

Main Results:

• Stalagmite data reveal a correlation between ITCZ position and global climate states during the Common Era.
• ITCZ expansion and weakening occurred during globally cold intervals.
• ITCZ contraction and intensification were observed during periods of global warmth.

Conclusions:

• The study supports models linking ITCZ dynamics to global temperature changes.
• Regions at the margins of the ITCZ are projected to experience increased aridity and climate variability.
• These hydroclimatic shifts may exacerbate existing social unrest and mass migration.