Sea level rise — even with low emissions — is fundamentally unpredictable using temporally
chaotic climate models.
Just because I want to do frontier research on
chaotic climate modeling doesn't mean I don't know anything about climate science, quite the opposite in fact.
Not exact matches
I am left with little alternative than to distrust any and all
models until more facts are in about this
chaotic climate of ours.
Hi, when I am discussing with
climate skeptics, they often refer to the third report of the IPCC (page 774): «In
climate research and
modelling, we should recognise that we are dealing with a coupled non-linear
chaotic system, and therefore that the long - term prediction of future
climate states is not possible.»
In
climate research and
modeling, we should recognize that we are dealing with a coupled non-linear
chaotic system, and therefore that the long - term prediction of future
climate states is not possible.
You say «That the
model simulations that you discuss in your weblog do not simulate rapid
climate transitions such as we document in our paper illustrates that the
models do not skillfully create
chaotic behavior over long time periods as clearly occurs in the real world.»
But, on the basis of studies of nonlinear
chaotic models with preferred states or «regimes», it has been argued, that the spatial patterns of the response to anthropogenic forcing may in fact project principally onto modes of natural
climate variability.
And I'm not aware of any
climate model that shows
chaotic behaviour on long time scales.
Eg the Lea et al 2002 paper I referenced above has the title «Sensitivity analysis of the
climate of a
chaotic ocean circulation
model».
That the
model simulations that you discuss in your weblog do not simulate rapid
climate transitions such as we document in our paper illustrates that the
models do not skillfully create
chaotic behavior over long time periods as clearly occurs in the real world.
So, while neither any
climate model nor any
climate data set I'm aware of show any signs of
chaotic behaviour of
climate (rather than weather), and the major
climate variations we know of can all be understood without needing to resort to chaos, I simply find no reason to believe there is chaos in
climate evolution.
Any state of the art
climate model (CGCM) under stationary forcing (plus annual cycle) will eventually demonstrate some sort of
chaotic behavior and / or will drift away from the realistic description of the actual atmosphere.
perhaps it's useful to think that
climate models are used to get an idea of the statistics of long - term weather conditions, but the weather itself remains
chaotic and will never be predictable beyond a week or so.
Samson wrote: when I am discussing with
climate skeptics, they often refer to the third report of the IPCC (page 774): «In
climate research and
modelling, we should recognise that we are dealing with a coupled non-linear
chaotic system, and therefore that the long - term prediction of future
climate states is not possible.»
In the case of
climate models, this is complicated by the fact that the time scales involved need to be long enough to average out the short - term noise, i.e. the
chaotic sequences of «weather» events.
When GCMs are used to
model atmospheric conditions and spatial grid size is reduced is there a scale at which
chaotic conditions prevail and make
modeling difficult in the same way that weather is harder to
model than
climate?
In particular, what are the implications for
climate modeling, and what do you tell a skeptic who pooh - poohs the
models because «it's
chaotic»?
So now you can say that
climate models have this «averaging over
chaotic behaviour» and weather
models don't?
Theoretician - climatologist on
climate calculation: We can
model our biosphere's
chaotic climate systems with enough confidence to know we are heading for a «big problem» if we don't mitigate CO2 emissions.
That the
climate is main unpredictable and that is behaviour is best
modelled as a
chaotic unpredictable system with small predictable perturbation.
The assertion by Tomas of the impossibility of analyzing
climate science due to
chaotic complexity is itself being torn to shreds by straightforward stochastic
models of the
climate such as manifested by the CSALT
model.
Using error - propagation the way it is done here shows precisely the same mistake that seems to appear in a lot of
climate models, a false assumption of linearity, starting from some conditions in a system that is physically strongly non-linear and numerically
chaotic.
Instead what is needed is an entirely different approach so far used by only a few researchers that does not attempt to build
models of coupled, non-linear
chaotic systems such as
climate.
Overcoming
chaotic behavior of
climate models.
Models are undoubtedly chaotic — it is the first thing that was understood about climate models way back in the 1
Models are undoubtedly
chaotic — it is the first thing that was understood about
climate models way back in the 1
models way back in the 1960's.
The actual
climate is incredibly complex and
chaotic, which makes it impossible for humans to predict
climate conditions, let alone «
model.»
So the
climate models are themselves temporal
chaotic dynamical systems.
-- such a
model would quickly depart from the unfolding
climate found on Earth because
chaotic systems defy prediction.
If you answered yes to the above question, then you don't believe that the Earth's
climate is completely and truely
chaotic and chaos in the Earth's
climate doesn't necessarily invalidate trends seen in global
climate models.
In addition we have the Tsonis network
model showing
chaotic linkages between
climate indices in the modern era.
Intuitively, the
models seem to be running hot because (a) their
climate response rate to doubling of CO2 is too high and (b) they do not adequately allow for negative feedbacks from clouds, among other influences which must remain beyond the realm of prediction due to their
chaotic nature.
They are basically worthless because they are trying to
model a coupled non-linear
chaotic system (
climate) which can not be usefully
modeled over even moderate periods of time.
Instead, we got a post by Tomas, who based on the comments by Jeff and the references in jstults» blog, seems rather ignorant on the research and literature in the field saying that «Hey,
climate is
chaotic and
climate scientists are doing it wrong», and insinuating therefore that all current
models aren't useful.
Regarding one other point you touched on, it's worth noting that
climate models do poorly with ENSO and other
chaotic variations, but well with long term temperature trends as a function of anthropogenic forcing.
If you were to produce a
chaotic model using the above, I would venture a prediction that the above former were the massive attractors about which we could make some decent predictions about the future but that the latter human produced CO2 inserted into our atmosphere would leave us with hopelessly inadequate and wrong predictions because CO2 contributed by man is not an attractor of any significance in the
chaotic Earth
climate system nor is CO2 produced by man a perturbation that would yield any predictive ability.
Actually supposing the
climate is somehow
chaotic one perhaps shouldn't expect a good fit from time - series
models driven by gaussian noise.
The problem in
climate science is that radiative theory is easier to
model than the
chaotic coupled fluid system that is our atmosphere and oceans.
The Tsonis et al paper in 2007 used a network
model to show
chaotic interactions of a few modes of
climate action.
In fact, it's my experience
modeling stochastic processes and noise (which are inherently
chaotic systems that can not be directly
modeled except as probability functions) that informs this next statement:
climate models can, and do,
model cloud formation.
If «[t] he inconvenient truth remains,» according to Philip Stott, that «
climate is the most complex, coupled, nonlinear,
chaotic system known,» then like flipping a coin, It will not matter if we devise a mathematical
model to combine the data of the last 100 flips with a dataset reflecting the 100 flips before that — even if you consider want to consider how many tails you got on the previous 1,000 flips — the odds for the next flip still will be 50 - 50.
This spread results because the
model equations provide a deterministic set of results that each can be different since the
climate is a
chaotic nonlinear system both in the
model, and even more so in the real world.
Yet the overriding difficulty in trying to
model the
climate is that it behaves as a
chaotic object.
The 2001 Intergovernmental Panel on
Climate Change (IPCC) Report that governments accept as certain predictions of future weather says, «In climate research and modeling, we should recognize that we are dealing with a coupled non-linear chaotic system, and therefore that the long - term prediction of future climate states is not possible.
Climate Change (IPCC) Report that governments accept as certain predictions of future weather says, «In
climate research and modeling, we should recognize that we are dealing with a coupled non-linear chaotic system, and therefore that the long - term prediction of future climate states is not possible.
climate research and
modeling, we should recognize that we are dealing with a coupled non-linear
chaotic system, and therefore that the long - term prediction of future
climate states is not possible.
climate states is not possible.»
Every measurement of key climatic variables has indicated that the «everything else being equal» lab experiments reflected in the
models is not realized in the dynamic and
chaotic climate.
There is a strong possibility that even perfect
climate models would be useless at predicting future
climate — if the
climate system were
chaotic.
... in
climate research and
modeling we should recognise that we are dealing with a complex non linear
chaotic signature and therefore that long - term prediction of future climatic states is not possible...
The first scientist who identified the
climate as a
chaotic system (still deterministic, but not predictable) was Edward Lorentz — also one of the first people to try
modeling it with computers.
My inital position was that
climate was too
chaotic to
model.
...
Models of our complex and
chaotic climate system simply don't make useful predictions after a few days» time.
Essentially,
climate models assume linear
climate relationships yet the real - world
climate is non-linear and
chaotic - defying intermediate and long - term predictive «expertise» with predictable regularity.