Earth’s history includes
many major ice ages,
-- 10 in the past
one million years,
and another 10 in the
one million years
before that.
Each major "glaciation"
lasts about 90,000 years,
followed by a 10,000-year
mild climate "interglacial".
We are currently in
a mild, warm climate
interglacial period,
called the Holocene.
Some scientists claim
the interglacial
we're now living in,
is the warmest period
of the past millennium.
“Unprecedented”
is often claimed.
Those are lies !
Glaciers began to form
over Antarctica at least
30 million years ago
and in the Northern
Hemisphere about
3 million years ago.
Today we are
actually experiencing
one of the
coldest climates
in the 4.5 billion year
history of our planet !
Antarctic ice cores,
over the past
800,000 years,
reflect cycles of
major glaciation,
followed by
interglacial periods,
in 100,000 year-cycles.
These "Milankovitch Cycles"
are very likely caused by the
eccentricity of Earth’s orbit,
and its axial tilt.
Milankovitch cycles are a set of
cyclic variations in characteristics
of the Earth's orbit around the Sun.
Each cycle has a different length,
so at some times their effects
reinforce each other,
and at other times
they (partially) cancel
each other.
There is strong evidence
that Milankovitch cycles
affect the occurrence
of glacial and interglacial
periods within an ice age.
That planetary geometry cycle
is much more likely
to cause a change
in temperature,
than a change in CO2.
We have high-quality
reconstructed temperature
records for the prior
four interglacials --
and all of them
were WARMER
than the current
interglacial !
The Russian
Vostok drilling station,
in East Antarctica,
provided a 420,000-year
history of Earth’s
near-surface
air temperature and
atmospheric CO2
concentration.
This record covers the current
interglacial period, and the prior
four interglacials.
The current interglacial
is the COLDEST
of the five most recent
interglacials !
The four interglacials
before the current
Holocene interglacial,
averaged +2° C. warmer,
in spite of CO2 levels
below 300 ppm, compared
with about 410 ppm today.
The only thing that's unusual
about today's air temperature,
is that it is so low (cool)
in spite of such a high
CO2 concentration.
Similar findings have been obtained
from the Dome Fuji ice core, located
about 1,500 km from the Vostok
ice core site.
That independent proxy
temperature record
reveals that the
past three interglacials
were much warmer,
by +4.5 to +6.0 degrees C.,
than the most recent
1,000 years.
Prior interglacial warmth,
+1 to +4 degrees C.
warmer than today,
was also found in a 550,000-year
sea surface temperature
dataset derived by
Herbert et al. (2001)
from marine sediment cores,
from the western coast
of North America,
from around 22°N latitude,
at the southern tip
of the Baja Peninsula,
to around 42°N latitude
off the coast of Oregon.
Herbert, T.D., Schuffert,
J.D., Andreasen,
D., Heusser, L., Lyle,
M., Mix, A., Ravelo, A.C.,
Stott, L.D., and Herguera, J.C.
2001.
"Collapse of the California Current
during glacial maxima
linked to climate change on land."
Science 293: 71– 76.
These climate proxy studies
ALL suggest that Earth’s
current temperature
does NOT reflect
unusual warmth !
The IPCC’s claim of a strong
human influence on today’s climate
is primarily based on their false claim
that Earth’s current temperature
is unusually warm !
Ice core studies also showed
Earth’s air temperature
rose 400 to 2,800 years
BEFORE any increase
in atmospheric CO2.
And increases in atmospheric CO2
did NOT trigger any of the major
global warmings that ended
the past three ice ages!
So carbon dioxide was NOT
the primary cause of the major
glacial-interglacial temperature
changes.
In fact, the CO2 content
of the air gradually ROSE
after the termination
of the last great ice age,
by approximately 25 ppm,
between 8,200 BC and 1,200 AD,
while global air temperature
DECLINED !
Interglacials also appear to have
a more stable climate,
than cooler glacial periods.
Antarctic ice core data
suggest the current
CO2 concentration
is 40% higher
than at any time
in the past 650,000 years.
And the current
methane concentration
is approximately
130% percent higher.
If the IPCC was correct
in attributing a huge
greenhouse warming effect
to these two greenhouse gases,
then Earth should now have
a MUCH WARMER temperature
than in the prior
interglacial periods.
But this did NOT happen !