The geological record
shows temperatures
and CO2 levels
in the atmosphere
have never
been stable,
making the
IPCC’s assumption
that they would be
stable in the future,
if there had been
no human emissions,
impossible to believe.
Rough estimates
of CO2 concentrations
in the atmosphere and
local surface temperatures,
in the distant past,
are extrapolated
from proxy data.
Examples of proxies
include
pollen analysis,
tree ring records,
speleothems,
characteristics of corals
and various data
derived from
marine sediments
and ice cores.
The best proxy data
come from
oxygen and hydrogen
isotopes in ice,
and CO2 in air bubbles
preserved in ice cores,
obtained by drilling
in Antarctica
and Greenland.
Reconstructions of
past climate conditions
are not actually data.
They rely on limited data
fed into computer models
and subject to interpretation
by scientists.
Proxy data
reveal temperatures
varied considerably
over the past
600 million years.
Earth’s orbital changes,
known as Milankovitch cycles
are the accepted explanation
for these broad changes
in temperatures.
Temperature and CO2
are lower today
than they have been
during most of the era
of modern life on Earth.
For more than
2.5 million years
(the Pleistocene Epoch)
the world was
in a cold period
with long glaciations
(“ice ages”)
interrupted by
relatively brief
warm periods
of typically
10,000 to 15,000 years.
On this time scale,
temperature and CO2
are without correlation.
We have been
in the current
Holocene Epoch
interglacial warm period
for about 11,500 years.
Within the Holocene,
there is strong
physical evidence
for periods of both
global warming
and global cooling,
though much less
extreme cycles
extreme cycles
than the Milankovitch
glaciation cycles.
Most of the “warm periods”,
or “climate optimums”,
are thought to have been
at least as warm
as Earth’s current climate.
Oxygen isotope data,
from the GISP2
Greenland ice cores ,
show the prominent
Medieval Warm Period (MWP)
occurring around 900–1300 A.D.
The Vikings took advantage
of the warmer climate
to colonize Greenland.
Virtually all species
of plant and animal life
in the world today arose,
evolved, and flourished
during periods
when atmospheric
CO2 levels
were much higher
than they are today.
Today’s species
will thrive
if CO2 levels rise
to several times
their current levels.
The geological record
also shows CO2 levels
are not stable.
Today’s CO2 level
is “unprecedented”
only because
CO2 is lower than
at most other points
in the geological record.
CO2 concentrations
in the atmosphere
typically rose
several hundred years
after temperatures rose,
indicating the
temperature increase
was not caused
by the CO2 rise.
The Vostok Antarctica
ice core is 3,310 meters long
and represents
422,766 years
of snow accumulation.
There is a persistent tendency
for CO2 to lag temperature
by at least hundreds of years,
up to several thousand years.
CO2 levels in the past
obviously played
a negligible role
in determining
the temperature.
During warmer
inter-glacial periods,
oceans absorb less CO2
or 'outgas' more of it
into the air.
Plant life
absorbs more CO2
from the air
during warm periods,
than during cold periods.
The rise in CO2 levels
since the beginning
of the Industrial Age
could have many causes:
(1)
Human CO2 emissions
from burning fossil fuels,
(2)
Changes to land use, and
(3)
Oceans outgassing CO2
in response to
natural cyclical warming.
During the present Pleistocene
Ice Age, CO2 had dropped
to dangerously low levels,
for plants to grow and survive.
Adding CO2 to the air was,
inadvertently, the best thing
humans have every done
to improve the ecology
on our planet !