Temperature variations during the past 20 ka at Huguangyan Maar Lake in
tropical China and dynamic link
Abstract
Discrepancies exist in global temperature evolution from the Last
Glacial Maximum to the present between model simulations and proxy
reconstruction. This debate is critical for understanding and evaluating
current global warming on a longer timescale. Here we report a branched
GDGTs-based temperature reconstruction from the sediments of Huguangyan
Maar Lake in southeast China and validate it using historical
documentary evidence and instrumental data. The reconstructed mean
annual air temperature (MAAT) indicates distinct changes during the last
deglaciation (Oldest Dryas, Bølling-Allerød, Younger Dryas). During the
Holocene, temperatures gradually increased from the end of the Younger
Dryas to ~7.0 ka BP, followed by a decrease in recent
decades. However, our terrestrial temperature record differs from model
simulations and proxy sea surface temperature records of the Holocene.
We conclude that ice volume or ice sheet is the most prominent forcing
that controlled the regional temperature evolution from the Last Glacial
Maximum to the beginning of the middle Holocene; while the temperature
variations during the middle and late Holocene were mainly regulated by
several possible factors, such as oceanic and atmospheric circulation,
and external drivers (solar and volcanic activity).