Clouds are hard for models to get right and we know that different climate models don't agree on how hot it's going to get, in large part because they don't agree on what clouds will do in the future.
Not exact matches
There are about 30
climate models available today, and each has slightly
different physics, which means their forecasts
do not always match.
A combination of circumstances makes
model - based sensitivity estimates of distant times and
different climates hard to
do, but at least we are getting a good education about it.
Full - complexity Earth system
models (ESMs) produce spatial and temporal detail, but an ensemble of ESMs are computationally costly and
do not generate probability distributions; instead, they yield ranges of
different modeling groups» semi-independent «best estimates» of
climate responses.
Not coincidentally this corresponds to the state - of - the - art of
climate models around 1980 when the first comparisons of
different forcings started to be
done.
Do different climate models give
different results?
The IPCC
did a comparison of
different climate models.
I haven't seen anything that very strongly supports the IRIS idea, but I
do concur with one idea buried in the paper: that the parameterization of fractional cloud cover in GCM's is not based on very clear physical principles, and could operate in many
different ways — some of which, I think, could make
climate sensitivity considerably greater than the midrange
model of the current crop.
There are hundreds of factors that influence the
climate in
different ways, how
do you manage to cram all of these into the calculations within the
model to accurately (as far as possible) represent the
climate?
All in all the science of hurricanes
does appear to be much more fun and interesting than the average
climate change issue, as there is a debate, a «fight» between
different hypothesis, predictions compared to near - future observations, and all that
does not always get pre-eminence in the exchanges about
models.
As
climate models had now proven the existence of
climate change, the organization's next focus will be on a
different vantage point: «What
do we
do about it [and] how can we find solutions for the
climate we will be living with?»
PAGE09 and DICE2013 have
different models of the
climate - economics interface and
different assumptions about social values, but they agree on what low
climate sensitivity
does in relative terms to the social cost of carbon.
So, people
do care when you are opposed to their point of view, it seems, so it is quite useful to show that I work with some of the top UK
climate scientists (via Tyndall), that I am involve in
climate policy
modelling (and
climate modelling via CIAS), so I don't get any patronising comments by anonymous people who claim I should be quiet because they «read the science» while I must be a PR guy if I want to engage with people with a
different opinion to myself.
While I am no scientist, this reluctance to agree to what a null hypothesis should be for AGW / CAGW is to me no
different from the defense of
climate models by claiming they
do not need to be validated, or claims that peer review of the published literature
does not need to ensure the correctness of the article being published.
Due to the important role of ozone in driving temperature changes in the stratosphere as well as radiative forcing of surface
climate, several
different groups have provided databases characterizing the time - varying concentrations of this key gas that can be used to force global
climate change simulations (particularly for those
models that
do not calculate ozone from photochemical principles).
I am not sure how that can
done as physically plausible
models themselves are non-linear but very
different non-linear systems to that of
climate.
The ten or twelve IPCC
climate models all had very
different climate sensitivities — how, if they have
different climate sensitivities,
do they all nearly exactly
model past temperatures?
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.
Lovely little anecdotes, but if an ATC system crashes on a busy day, people's lives are at risk whereas if a
climate model crashes (due to a system or process error rather than a numerical error), it can be re-run — as long as the error doesn't cause
different results to occur, ie.
If the two methods
do lead to
different estimates of
climate sensitivity, I find it difficult to believe that the 1D
model is more appropriate than 3D to making claims about how much the real average temperature will rise due to a given influence.
I'm going to assume you aren't claiming that most
climate scientists don't understand that there are issues with the
models, that
different models give
different results, that as we move in time the
models are less likely to be accurate, and that the
models are just that
models and not complete realistic representations of
climate.
Italian flag analysis: 30 % Green, 50 % White, 20 % Red (JC Note: all
climate models produce this result in spite of
different sensitivities and using
different forcing data sets; the
models do not agree on the causes of the early 20th century warming and the mid-century cooling and
do not reproduce the mid-century cooling.)
The IPCC is straightforward in its introduction to attribution and doesn't claim anything other than that attribution needs some kind of
modelling (because we can't put the
climate in a bottle) and that this method relies on a number of
different tactics, including the consensus of what these tactics mean of the experts.
I
do recall that proposed physical causes for abrupt
climate change include orbital variations and combinations of feedbacks... and none of this negates the
different drivers /
modeling approaches for weather systems versus
climate.
If Mr. Rose really wants to improve his reporting and
do a general service of advancing a true understanding of the issue of anthropogenic
climate change, he needs to
do a comprehensive article about Earth's energy budget, and state quite clearly all the
different spheres (all layers of the atmosphere, hyrdosphere, crysosphere, and biosphere) in which the signal of anthropogenic warming is both
modeled as impacting and then talk about what is data is actually saying in terms of Earth's energy imbalance in all these spheres.
In a system such as the
climate, we can never include enough variables to describe the actual system on all relevant length scales (e.g. the butterfly effect — MICROSCOPIC perturbations grow exponentially in time to drive the system to completely
different states over macroscopic time) so the best that we can often
do is
model it as a complex nonlinear set of ordinary differential equations with stochastic noise terms — a generalized Langevin equation or generalized Master equation, as it were — and average behaviors over what one hopes is a spanning set of butterfly - wing perturbations to assess whether or not the resulting system trajectories fill the available phase space uniformly or perhaps are restricted or constrained in some way.
However he has
done nothing
different from what the
climate science community has
done except that they have encapsulated these approximations into complex
models.
Much of their seminal research has been exposed as academic fraud, based on cute little games like ignoring large periods of history that don't conform to their man - made
climate change
models, fudging temperature measurements, and changing the methodology for recording and estimating global temperatures at during
different historical periods.
Different vegetation
models driven with similar
climate projections also show Amazon dieback (82), but other global
climate models (83) project smaller reductions (or increases) of precipitation and, therefore,
do not produce dieback (84).
Sensitivity analysis shows that
different assumptions of
climate sensitivity, carbon cycle
model or scenario
do not substantially change the outcome.
You might as well use a ouija board as the basis of claims about the future
climate history as the ensemble average of
different computational physical
models that
do not differ by truly random variations and are subject to all sorts of omitted variable, selected variable, implementation, and initialization bias.
The Seasonal and
Climate Applications group of the Finnish Meteorological Institute is composed of internationally known experts who do research on the post-processing possibilities and usage of different scale weather and climate predictions
Climate Applications group of the Finnish Meteorological Institute is composed of internationally known experts who
do research on the post-processing possibilities and usage of
different scale weather and
climate predictions
climate predictions
models.
Comparing the
model temperature anomalies with observed temperature anomalies, particularly over relatively short periods, is complicated by the acknowledgement that
climate models do not simulate the timing of ENSO and other modes of natural internal variability; further the underlying trends might be
different.
For example, Stainforth et al. (2005) have shown that many
different combinations of uncertain
model sub-grid scale parameters can lead to good simulations of global mean surface temperature, but
do not lead to a robust result for the
model's
climate sensitivity.
In the latter case, the alternative relative SST measure in the lower panel
does not change very much over the 21st century, even with substantial Atlantic warming projections from
climate models, because, crucially, the warming projected for the tropical Atlantic in the
models is not very
different from that projected for the tropics as a whole.
Now I know the budgets / development environments are
different but that still doesn't relieve the burden of at least verification from any
climate model used to shape even 1 dollar of policy.