One can dismiss Beenstock and Reingewertz because they are wading into an area
of statistical uncertainty, but any of us who are making inferences about temperature trends should realize we are all wading in the same waters.
What is the justification for adjusting past values, and is there any way to convey the increasing level
of statistical uncertainty in the USHCN values, like confidence intervals or error bars on charts?
As well, the statement «Whether we have the 1000 year trend right is far less certain» is in fact an admission of the lack of sufficient knowledge about the correctness of the application of the reconstruction procedure and really should not be interpreted as a scientific assessment
of statistical uncertainty.
Hardly within the limits
of statistical uncertainty.
At nearly a dozen other sites, the authors report, the chronological results are neither reliable nor valid as a result of significant statistical flaws in the analysis, the omission of ages from the models, and the disregard
of statistical uncertainty that accompanies all radiometric dates.
The usual health warnings were issued in the form
of statistical uncertainty estimates, but these invitations to prudence were given less attention than they deserved by most consumers of the numbers.
Such issues of robustness need to be taken into account in estimates
of statistical uncertainties.
The biggest problem, I believe, with the IPCC reports is the lack of discussion
of statistical uncertainties.
Not exact matches
Until, and once the
uncertainty is reduced, THEN we can get back to a cyclic economy with
statistical smoothing that offers better predictions
of our future.
there's really no room for the concept
of an independent entity possessed
of «will» in a worldview shaped by cause and effect; the only place for «will» to retreat to is the zone
of true randomness,
of complete
uncertainty, which means that truly free will as such must be completely inscrutible [sic]...
Statistical laws govern the decay
of a block
of uranium, but whether or not this atom
of uranium chooses to fission in this instant is a completely unpredictable event — fundamentally unpredictable, something which simply can not be known — which is equally good evidence for the proposition that it's God's (or the atom's) will whether it splits or remains whole, as for the proposition that it's random chance.
The new approach contrasts with previous ways scientists analyzed and came to conclusions about sea level rise because it is «the only proper one that aims to fully account for
uncertainty using
statistical methods,» noted Parnell, principal investigator
of the study conducted collaboratively with researchers at Tufts University, Rutgers University and Nanyang Technological University.
In her doctoral thesis, Henni Pulkkinen, Researcher at the Natural Resources Institute Finland (Luke), explored how the various sources
of uncertainty can be taken into account in fisheries stock assessment by using Bayesian
statistical models, which enable extensive combining
of information.
This is intended to take account
of some
of the
uncertainties inherent in data on whale populations, and requires only two kinds
of data: current estimates and their
statistical error; and historical details
of catches.
The journal Basic and Applied Social Psychology recently banned the use
of p - values and other
statistical methods to quantify
uncertainty from significance in research results
The U.S. Bureau
of the Census is locked in a high - stakes political battle with Congress over a plan to reduce
uncertainties in the year 2000 survey through
statistical techniques rather than direct head counts.
The criteria should be applied on the basis
of the available evidence on taxon numbers, trend and distribution, making due allowance for
statistical and other
uncertainties.
Carling Hay et al. provide a
statistical reassessment
of the tide gauge record which is subject to bias due to sparse and non-uniform geographic coverage and other
uncertainties and conclude that sea - level rose by about 1.2 millimetres per year from 1901 to 1990.
However, one
of the panel's reservations was that ``... a
statistical method used in the 1999 study was not the best and that some
uncertainties in the work «have been underestimated,»...» The panel concluded «Based on the analyses presented in the original papers by Mann et al. and this newer supporting evidence, the committee finds it plausible that the Northern Hemisphere was warmer during the last few decades
of the 20th century than during any comparable period over the preceding millennium.
We will continue to learn more about nutrition as science progresses, but we should have a better foundation than a handful
of unexplained
statistical correlations on which to act in the face
of uncertainty.
All
of the relationships have
statistical uncertainty.
Having said that, I do like the idea
of combining
statistical and structural
uncertainty into one measure.
(in general, whether for future projections or historical reconstructions or estimates
of climate sensitivity, I tend to be sympathetic to arguments
of more rather than less
uncertainty because I feel like in general, models and
statistical approaches are not exhaustive and it is «plausible» that additional factors could lead to either higher or lower estimates than seen with a single approach.
To convert that into a useful time - varying global mean needs a
statistical model, good understanding
of the data problems and enough redundancy to characterise the
uncertainties.
I believe that statisticians can contribute more to climate sciences in better description
of the
uncertainties, in addition to better calibration
of statistical models.
When I read the media PR on this, it looked like BEST claimed better
statistical methods, leading to lower estimates
of the
uncertainty in the temperature change - even at the decadal level.
Although some earlier work along similar lines had been done by other paleoclimate researchers (Ed Cook, Phil Jones, Keith Briffa, Ray Bradley, Malcolm Hughes, and Henry Diaz being just a few examples), before Mike, no one had seriously attempted to use all the available paleoclimate data together, to try to reconstruct the global patterns
of climate back in time before the start
of direct instrumental observations
of climate, or to estimate the underlying
statistical uncertainties in reconstructing past temperature changes.
These authors have shown that the «alternative» reconstruction promoted by McIntyre and McKitrick (which disagrees not only with the Mann et al reconstruction, but nearly a dozen independent reconstructions that agreee with the Mann et al reconstruction within
statistical uncertainties) is the result
of censoring
of key data from the original Mann et al (1998) dataset.
In fact, the nominal
statistical significance levels
of all statements are quite a bit stronger than we assess them couched in likelihood language, in order to account for remaining
uncertainties.
The pitfalls
of producing
statistical judgements are endless, however I just want to note that it is only right at the very, very end (within just a few years
of 1980) that the instrumental record or any
of the proxies, first emerge above any
of the possible projected lines that can be drawn through the
uncertainty envelope.
In other words, it is possible that the the climate system does exhibit some kind
of long - term chaos in some circumstances, but that the forcing is strong enough to wipe out any significant
uncertainty due to initial conditions — at least if one is content to forecast
statistical quantities such as, for example, decadal mean January temperatures in some suitably large region, or perhaps temperature variances or quartiles taken over a similar period.
Cox et al. provide a
statistical uncertainty range for a single study, ignoring structural
uncertainty and systematic biases resulting from their choice
of model and method.
The IPCC range, on the other hand, encompasses the overall
uncertainty across a very large number
of studies, using different methods all with their own potential biases and problems (e.g., resulting from biases in proxy data used as constraints on past temperature changes, etc.) There is a number
of single studies on climate sensitivity that have
statistical uncertainties as small as Cox et al., yet different best estimates — some higher than the classic 3 °C, some lower.
So: The study finds a fingerprint
of anthropogenic influences on large scale increase in precipitation extremes, with remaining
uncertainties — namely that there is still a possibility that the widespread increase in heavy precipitation could be due to an unusual event
of natural variability.The intensification
of extreme rainfall is expected with warming, and there is a clear physical mechanism for it, but it is never possible to completely separate a signal
of external forcing from climate variability — the separation will always be
statistical in nature.
I will argue that the
uncertainties make it necessary to look at many different methods for downscaling (regional climate models and
statistical downscaling) as well as the largest possible range
of (sensible) GCMs.
This work is complicated, involving lots
of statistical methods in extrapolating from scattered sites to a global picture, which means that there's abundant
uncertainty — and that there will be abundant interpretations.
I advise military evaluators to RIGOROUSLY assess the assumptions
of statistical models (not to be confused with physical processes) upon which climate scientists, solar scientists, etc. base estimates
of uncertainty.
Unfortunately it shows, in my judgment, a current tendency by this group
of scientists and their supporters to react by down grading some serious and basic
statistical errors and inabilities to place
uncertainty measures on results to a level
of «minor» flaws and to characterize the criticisms as personal attacks.
And I really wish people wouldn't talk about «
statistical uncertainty»
of models.
There is currently no consensus on the optimal way to divide computer resources among finer numerical grids, which allow for better simulations; greater numbers
of ensemble members, which allow for better
statistical estimates
of uncertainty; and inclusion
of a more complete set
of processes (e.g., carbon feedbacks, atmospheric chemistry interactions).
Our experiments suggest that both
statistical approaches should yield reliable reconstructions
of the true climate history within estimated
uncertainties, given estimates
of the signal and noise attributes
of actual proxy data networks.
Given the
statistical uncertainty in determining pre-1800s temperatures (see graph below) that requires greater than 50 %
of the warming be attributed to anthropogenic factors.
To me that is completely irrelevant, because it was already known that there are limits
of modeling performance that are stricter that those set by the
statistical uncertainties.
Instead, we find that «
uncertainty» is actually being used to express the
statistical PRECISION
of the computer modeling output sets with respect to each other, not with respect to the real world.
If we have inadequate sampling, and short time intervals, the
statistical uncertainties from random fluctuations and random measurement errors can be large, but would tend to cancel out as the number
of observations and length
of time increases.
As a «rule
of thumb», bias (Type B)
uncertainties may be similar to
statistical (Type A)
uncertainties.
It seems to me that the issue is not so much that the IPCC AR4 chapter 9 authors have made an error in determination
of the sensitivity in Fig 9.20, but rather that there is unacknowledged structural
uncertainty in their methods for determining climate sensitivity (both
statistical and physical / conceptual).
Improvements in seasonal forecasting practice arising from recent research include accurate initialization
of snow and frozen soil, accounting for observational
uncertainty in forecast verification, and sea - ice thickness initialization using
statistical predictors available in real time.
Data from the ERSSTv3b and COBE data sets were also used in place
of HadISST1 and gave similar results suggesting that the
uncertainties do not depend strongly on the
statistical assumptions made in creating HadISST1.
Thus tolerance for Risk is meaningless in such questions;
Uncertainty removes all sense
of Risk entirely, no cost / benefit formulation, no
statistical distribution containing a mean, no Risk preference can be expressed.
In his talk, «
Statistical Emulation
of Streamflow Projections: Application to CMIP3 and CMIP5 Climate Change Projections,» PCIC Lead
of Hydrological Impacts, Markus Schnorbus, explored whether the streamflow projections based on a 23 - member hydrological ensemble are representative
of the full range
of uncertainty in streamflow projections from all
of the models from the third phase
of the Coupled Model Intercomparison Project.