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Friday, April 3, 2020

Future global warming estimates from the latest computer games (CMIP6) have no constraints

Several climate models 
of the latest Sixth Coupled 
Model Inter-comparison 
Project ( CMIP6 ) 
predict much stronger 
global warming,
inconsistent with past 
assessments ( CMIP5 ). 

You would think future 
warming predictions 
would be constrained 
by the measured 
global warming
in the past.

Think again -- 
climate computer
games have
no constraints.


The Intergovernmental 
Panel on Climate Change 
              ( IPCC ) 
Assessment Reports, 
and national climate
scenarios, rely heavily 
on results of multiple 
climate model 
simulations, 
collected in model 
inter-comparisons. 

Climate model 
inter-comparisons 
have always featured 
diverging 
model projections, 
for the question of
how much global
warming to expect 
for a doubling 
of the global 
atmospheric CO2 
concentration. 

The multi-model average 
may be biased high, or low, 
when many models 
are biased the same way, 
or when near-duplicate 
models are included.

The long-term 
warming range
of the Coupled Model 
Inter-comparison Project 
Phase 5 (CMIP5) models 
was interpreted in the
IPCC Fifth Assessment 
Report ( AR5 ).

Phase 6 ( CMIP6 ) 
of the Coupled Model 
Inter-comparison Project 
will be the basis for the 
upcoming Sixth  IPCC
Assessment Report (AR6).

The first models submitted 
to the archive suggest 
that CMIP6 will span 
a wider range of warming
responses to CO2 
than CMIP5. 

Several new CMIP6 models 
have equilibrium climate 
sensitivity (ECS) 
values higher 
than the 
CMIP5 models
( they are predicting 
even more warming )

One third 
of CMIP6 models 
submitted to date
 ( 10 of 29 models ) 
exceed the range 
of +1.5° to +4.5°C
for ECS 
assessed 
as likely 
(17% to 83% range) 
in the prior
IPCC AR5 
report. 

Higher climate sensitivity 
(to CO2) values mean 
future climate projections 
from these models 
will show stronger future 
global average warming
than the global warming 
previously reported
in AR5.

A more near-term 
    ( transient ) 
global warming 
that arises 
after 70 years
of a 1% per year
increase in 
atmospheric CO2 
concentration, 
is referred to as the
transient climate
response ( TCR ). 

Climate models 
have consistently 
overestimated 
the future 
global warming 
by 2x to 3x.

Models, of course, 
predict whatever 
their owners want 
predicted.

An honest modeler 
would want his or her 
climate model to predict 
LESS warming for CMIP6, 
so the new prediction
would be more accurate, 
when compared with 
actual measurements.

Apparently the
climate modelers 
don't really care 
about accurate 
predictions, 
and they
have not cared 
since the 1960s !

Every climate modeler 
on a government payroll, 
or taking a government grant, 
has been hired to predict 
a coming climate crisis.

And they do what 
they are paid to do !