“Study: Antarctic Waters Released Ancient Carbon at End of Ice Age—A Warning for Today’s Climate”
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A growing body of scientific evidence suggests that the end
of the last Ice Age, around 12,000 years ago, triggered major shifts in
deep-ocean circulation around Antarctica—changes that unlocked massive stores
of ancient carbon sealed away in the ocean’s depths. As this carbon entered the
atmosphere, it contributed to the rapid warming that defined the early
Holocene. According to new research, the expansion of Antarctic Bottom Water
(AABW) played a central role by displacing long-isolated, carbon-rich
waters.
How Changing Antarctic Currents Released Long-Stored Carbon
A new paper published in Nature analyzed nine
sediment cores collected from the Southern Ocean, taken from depths between
2,200 and 5,000 meters across the Atlantic and Indian sectors. Researchers
measured the isotopic signature of neodymium, a trace metal used to
identify the origins of water masses, enabling them to reconstruct deep-ocean
circulation patterns over the past 32,000 years.
During the peak of the Ice Age, deep waters moved very
slowly, creating layers that prevented mixing and allowed carbon to accumulate
for millennia. As global temperatures began to rise roughly between 18,000
and 10,000 years ago, AABW expanded in two significant pulses. This
strengthened circulation disturbed the stagnant layers of the deep ocean,
pushing ancient carbon upward and eventually releasing it into the atmosphere.
The study suggests that these southern-hemisphere
circulation changes had a much larger role in Ice-Age carbon release than
previously recognized.
Implications for Today’s Rapidly Warming Climate
Modern observations show that the Southern Ocean has
temporarily been acting as a carbon sink because fresh surface water—from
melting ice sheets and increased precipitation—helps stabilize stratification
and keeps CO₂ trapped at depth. However, this balance may not hold.
If warming seas and intensifying winds break down that
layered structure, similar to what occurred at the end of the last Ice Age, the
deep ocean could once again release stored carbon into the atmosphere. Such a
shift would accelerate global warming and complicate efforts to manage Earth’s
carbon budget.
The new findings underscore how sensitive Antarctic-driven
circulation is—and how crucial it is to track polar changes as climate
pressures increase.
#ClimateScience #Antarctica #IceAgeResearch #CarbonCycle
#OceanCirculation #ClimateChange #HoloceneWarming #SouthernOcean #EarthScience
#GlobalWarming
