Elements,
Год журнала:
2025,
Номер
21(2), С. 98 - 104
Опубликована: Апрель 1, 2025
The
atmospheric
partial
pressure
of
CO2
(pCO2)
is
the
key
driver
climate
variability.
Boron
isotopic
compositions
(δ11B)
marine
calcium
carbonates
reveal
pCO2
geologic
past
because
boron
isotope
incorporation
sensitive
to
seawater
pH,
which
closely
reflects
pCO2.
Biocarbonate
δ11B
values
record
environmental
pH
through
a
metabolic
prism
(so
called
“vital
effects”),
sometimes
complicating
interpretations.
However,
biocarbonate
isotopes,
coupled
with
concentrations
(B/Ca),
can
also
processes
calcification.
Here,
we
review
link
between
and
effective
recorded
by
organisms
via
biomineralisation
summarise
reconstructions
from
isotopes
for
Cenozoic
(≈70
Ma
modern
times),
arguably
most
significant
contribution
this
proxy
system
date.
The
Phanerozoic
climate
has
been
interrupted
by
two
long
"icehouse"
intervals,
including
the
current
icehouse
of
last
~34
million
years.
While
these
cool
intervals
correspond
to
lower
atmospheric
CO2,
it
is
unclear
why
CO2
levels
fell,
with
hypotheses
suggesting
changes
in
degassing
rates
or
modification
silicate
weathering
through
changing
continental
lithology
paleogeography.
Here,
we
construct
an
Earth
System
Model
that
integrates
proposed
cooling
mechanisms
detail.
model
can
reproduce
broad
geologic
record
ice
cap
expansion,
allowing
us
infer
primary
drivers
long-term
change.
Our
results
indicate
recent
climates
required
a
combination
different
acting
simultaneously
and
were
not
driven
single
known
process,
potentially
explaining
icehouses
have
rarer
than
greenhouses
over
history.
Geophysical Research Letters,
Год журнала:
2025,
Номер
52(7)
Опубликована: Апрель 1, 2025
Abstract
During
the
early‐to‐middle
Miocene,
global
mean
surface
temperature
(GMST)
was
approximately
8°C
warmer
than
preindustrial,
with
a
greater
increase
in
polar
regions
tropics.
However,
existing
Miocene
simulations
underestimate
this
warmth,
particularly
northern
high
latitudes.
To
address
discrepancy,
we
investigate
potential
role
of
cloud
phase.
Using
Community
Earth
System
Model,
conduct
paleoclimate
sensitivity
study
focused
on
modifying
ice
nucleation
and
phase
partitioning
schemes.
These
modifications
GMST,
strong
rise
latitudes
muted
increases
are
driven
by
enhanced
longwave
forcing,
resulting
from
increased
amounts
water
content,
amplified
vapor
lapse
rate
feedbacks
Arctic.
Our
highlights
that
improved
parameterizations
processes
enhance
models'
capability
to
simulate
high‐latitude
warmth
potentially
other
warm
climates.
Elements,
Год журнала:
2025,
Номер
21(2), С. 98 - 104
Опубликована: Апрель 1, 2025
The
atmospheric
partial
pressure
of
CO2
(pCO2)
is
the
key
driver
climate
variability.
Boron
isotopic
compositions
(δ11B)
marine
calcium
carbonates
reveal
pCO2
geologic
past
because
boron
isotope
incorporation
sensitive
to
seawater
pH,
which
closely
reflects
pCO2.
Biocarbonate
δ11B
values
record
environmental
pH
through
a
metabolic
prism
(so
called
“vital
effects”),
sometimes
complicating
interpretations.
However,
biocarbonate
isotopes,
coupled
with
concentrations
(B/Ca),
can
also
processes
calcification.
Here,
we
review
link
between
and
effective
recorded
by
organisms
via
biomineralisation
summarise
reconstructions
from
isotopes
for
Cenozoic
(≈70
Ma
modern
times),
arguably
most
significant
contribution
this
proxy
system
date.
