The global climate models
do NOT capture the
significant global warming
from 1910 to 1940
( back tested ),
the cooling from
1940 to the late 1970s
( back tested ),
and the relatively flat
temperature trend
from 1998 through 2018.
That's a very low
"batting average"
for 108 years !
The key conclusion of the
IPCC's Fifth Assessment Report:
It's "extremely likely"
"more than half" of the
warming since the
mid- 20th century
( assumed to mean 1950 )
has been caused by humans,
and climate model simulations
indicate all of the warming
has been caused by humans.
The above claim is
complete nonsense:
It is a logical fallacy
called an 'argument
from authority',
and "extremely likely"
is NOT a scientific term.
The IPCC statement
can be corrected
ONLY IF
"extremely likely"
is replaced with
"possible",
and the part about climate
models is tossed in the
garbage, where it belongs.
Natural causes
of climate change
could have been
responsible for 100%
of the mild warming
since 1975
-- no one knows --
and merely asserting
that you do know,
does not create 'truth'.
If the warming since 1950
was caused by humans,
then what caused the
warming from 1910–1940 ?
The period from 1910–1940
is claimed to be about 40%
of the warming since 1900,
but is associated with only 10%
of the CO2 increase since 1900 !
And the mid-century period
of slight global cooling,
from 1940 to 1975,
has never been
satisfactorily explained.
In addition to those
unexplained variations
in 20th century
temperatures,
there's evidence
the global climate
has been warming
for the past 300 years.
Historical data are sparse
for the 1800's,
but the Berkeley Earth
Surface Temperature Project
assembled the available
temperature data, over land,
since1750.
The Berkeley Earth analysis
shows a warming trend back
to 1800, with a lot of variability
around the turn of the 19th century.
Central England real time
temperatures show warming
since the 1690s.
Paleoclimate reconstructions of
Northern Hemisphere climate,
such as from tree rings
and boreholes, indicate
overall warming for
the past 300 to 400 years.
What could be the cause
300 to 400 years
of global warming ?
Maybe the sun and the oceans ?
There's no reason
to blame humans
for the warming
from the late 1600s
through at least 1975
-- that can't be explained
by carbon dioxide,
and is only
partly explained
by volcanic eruptions
blocking sunlight.
The warming trend
in the average
climate model's
simulations of the
future climate,
is quadruple
the actual
warming rate
since 1940.
Climate alarmists
like to pretend
the global cooling
from 1940 to 1975,
which happened
while a lot of CO2
was being added
to the atmosphere,
never happened.
In a decade, I expect
climate alarmists will have
"adjusted away" most,
or all, of that cooling period,
just as they have been
gradually "adjusting away"
the very warm 1930s,
with many "adjustments"
over the past two decades.
Forget about a logical 1940
starting point for now,
for examining the effect
of man made CO2 from
fossil fuel burning.
Let's cherry pick 2000
as a starting point,
to make the climate models
look better: The GCMs are
still warming much too fast !
On average, models predicted
warming at a rate twice as fast
as the measured temperature
increase since 2000 !
Climate model projections
of global temperature change
at the end of the 21st century
are driving loud calls for
CO2 emissions reductions.
That's the ONLY reason
climate models matter !
For climate model projections.
RCP8.5 is an extreme
CO2 emissions scenario.
With the ridiculous
RCP8.5 scenario,
the CMIP5 climate model
group projects continued
warming that will surpass
the (nonsense)
"dangerous threshold"
of +2 degrees C. warming
( since 1750 ), by the year 2040.
Climate models have always
been running much too hot,
and the actual climate sensitivity
to carbon dioxide is, at worst,
below the lower end of the
large range provided by the IPCC.
The combination
of climate models
that grossly overestimate
global warming,
with the RCP8.5 guess,
that grossly overestimates
CO2 emissions ( a return
to a coal powered world
in the future ), adds up to
the following conclusion
about climate computer games,
stated in scientific terminology:
The computer games
are a steaming pile
of farm animal digestive
waste products,
being abused
by leftist politicians
to scare people,
with the goal of increasing
their power to tell you
how to live your life !