非表示:
キーワード:
-
要旨:
The Asian monsoon system is an important tipping element in Earth’s climate with a large impact on human
societies in the past and present. In light of the potentially
severe impacts of present and future anthropogenic climate
change on Asian hydrology, it is vital to understand
the forcing mechanisms of past climatic regime shifts in the
Asian monsoon domain. Here we use novel recurrence network
analysis techniques for detecting episodes with pronounced
non-linear changes in Holocene Asian monsoon
dynamics recorded in speleothems from caves distributed
throughout the major branches of the Asian monsoon system.
A newly developed multi-proxy methodology explicitly considers
dating uncertainties with the COPRA (COnstructing
Proxy Records from Age models) approach and allows for
detection of continental-scale regime shifts in the complexity
of monsoon dynamics. Several epochs are characterised
by non-linear regime shifts in Asian monsoon variability, including
the periods around 8.5–7.9, 5.7–5.0, 4.1–3.7, and
3.0–2.4 ka BP. The timing of these regime shifts is consistent
with known episodes of Holocene rapid climate change
(RCC) and high-latitude Bond events. Additionally, we observe
a previously rarely reported non-linear regime shift
around 7.3 ka BP, a timing that matches the typical 1.0–1.5 ky
return intervals of Bond events. A detailed review of previously
suggested links between Holocene climatic changes in
the Asian monsoon domain and the archaeological record indicates
that, in addition to previously considered longer-term
changes in mean monsoon intensity and other climatic parameters,
regime shifts in monsoon complexity might have
played an important role as drivers of migration, pronounced cultural changes, and the collapse of ancient human societies.
