Sentences with phrase «about natural variability in»
Within the limits of available data they address intriguing questions about the natural variability in the Arctic.
https://judithcurry.com/ Not exact matches
Some experiments were considered quirky by 19th century standards, but the work provided data supporting Darwin's notions about trait variability in a population and how natural selection drives changes in populations over time.
See also the comment of Wielicki and Chen at the NASA page and the next page about natural variability and the performance of the models in the tropics.
About natural variability and sensitivity for man - made GHGs, here I disagree with Raypierre in another (large) comment...
In addition you must of course factor in what we know about the current natural variabilitIn addition you must of course factor in what we know about the current natural variabilitin what we know about the current natural variability.
Thus, given natural variability, 20 years is only enough time to start tell apart (in a statistical significant fashion) trends that are at least disparate by about 0.15 ºC / decade.
The interest in these records is for what they can tell us about natural variability, spatial patterns of change, responses to solar or volcanic forcing, teleconnections etc. — it's all interesting and useful, but it is nothing like as important as the outside interest shown in these studies might suggest.
This analysis will reveal new insights about model biases, their causes, and about the role of natural variability in long - term change.It is possible that this analysis will change the predicted timing of the «ice free summers» but large uncertainties will likely remain.
While it has gotten about one degree warmer since 1900, there is no clear evidence that current climate is anywhere outside of natural variability, and mankind is, at this time, successfully living in climate extremes ranging from the far North to the Equator where climate differences are much more than 3C.
In so far as M&M are trying to distort the climate data over the last 1000 years to show that the so - called «Medieval Warm Period» replicates or exceeds the current warming — and so natural variability could possibly account for that warming — I thought it worthwhile to put out some information about Medieval climate.
[Response: Since I spend about half the time of my day job looking at natural variability in the pre-anthropogenic period, I have no idea why you think that I don't understand its value — try reading some of my papers: Schmidt et al (2004) for instance.
About natural variability and sensitivity for man - made GHGs, here I disagree with Raypierre in another (large) comment...
Question: before talking about simulating climate CHANGE, how long does the climate science community expect it to take before GCM's can reproduce the real world climate PRIOR to human induced CO2 perturbation in terms of: — «equilibrium point», i.e. without artificial flux adjustment to avoid climatic drift, — «natural variability», in terms of, for instance, the Hurst coefficient at different locations on the planet?
In many cases, it is now often possible to make and defend quantitative statements about the extent to which human - induced climate change (or another causal factor, such as a specific mode of natural variability) has influenced either the magnitude or the probability of occurrence of specific types of events or event classes.»
See also the comment of Wielicki and Chen at the NASA page and the next page about natural variability and the performance of the models in the tropics.
In reality we've seen about 0.5 — 0.6 °C of warming above mid-20th Century temperature, so perhaps at the 5σ level or 99.9 % confidence that the warming is due to external forcing (principally CO2) rather than natural variability.
My colleagues and I were using what we call proxy records, like corals and tree rings, and ice cores to try and extend the climate record back in time so that we could learn more about natural climate variability.
AIUI Hansen addresses that in the paper when he talks about the range of unforced natural variability — it's illustrated in Fig. 7.
The disagreement arises from different assessments of the value and importance of particular classes of evidence as well as disagreement about the appropriate logical framework for linking and assessing the evidence — my reasoning is weighted heavily in favor of observational evidence and understanding of natural internal variability of the climate system, whereas the IPCC's reasoning is weighted heavily in favor of climate model simulations and external forcing of climate change.
There is also a natural variability of the climate system (about a zero reference point) that produces El Nino and La Nina effects arising from changes in ocean circulation patterns that can make the global temperature increase or decrease, over and above the global warming due to CO2.
Right now the consensus view is that it is too early to say if global warming has already brought about a detectable change in the number and nature of tropical storms — the changes seen so far are still within the bounds of natural variability.
The U.S. military seems interested in climate variations / change on timescales from seasonal to scales out to about 30 years, a period over which natural climate variability could very well swamp anthropogenically forced climate change.
In my earlier posting, I tried to make the distinction that global climate change (all that is changing in the climate system) can be separated into: (1) the global warming component that is driven primarily by the increase in greenhouse gases, and (2) the natural (externally unforced) variability of the climate system consisting of temperature fluctuations about an equilibrium reference point, which therefore do not contribute to the long - term trenIn my earlier posting, I tried to make the distinction that global climate change (all that is changing in the climate system) can be separated into: (1) the global warming component that is driven primarily by the increase in greenhouse gases, and (2) the natural (externally unforced) variability of the climate system consisting of temperature fluctuations about an equilibrium reference point, which therefore do not contribute to the long - term trenin the climate system) can be separated into: (1) the global warming component that is driven primarily by the increase in greenhouse gases, and (2) the natural (externally unforced) variability of the climate system consisting of temperature fluctuations about an equilibrium reference point, which therefore do not contribute to the long - term trenin greenhouse gases, and (2) the natural (externally unforced) variability of the climate system consisting of temperature fluctuations about an equilibrium reference point, which therefore do not contribute to the long - term trend.
Data over 140 years is insufficient to make over broad claims about natural variability and it would require a leap of imagination to use this data in and of itself to draw conclusions about cause and effect.
However there is considerable uncertainty and disagreement about the most consequential issues: whether the warming has been dominated by human causes versus natural variability, how much the planet will warm in the 21st century, and whether warming is «dangerous».
Paleo evidence have indeed shown quite strong spikes in temperature anomolies which gets back to the most important point of your paper with Judith: the extent of natural internal variability needs to be disentangled from anthropogenic and other forcings before we can make any conclusions about the future course of climate.
The governing assumption in the vast majority of GCM / climate studies is that natural variability is a) small, b) integrates to zero over time and therefore its un interesting when it comes to answering the questions we care about: How much warming will human forcing cause.
Well, maybe there's an element of natural variability in the global climate that doesn't care about your SUV any more than it did back in the medieval warm period.
In 1990, two years after NASA scientist James E. Hansen issued his now famous warning about climate change during a congressional hearing, Lindzen started taking a publicly contrarian stance when he challenged then - senator Gore by suggesting in the Bulletin of the American Meteorological Society that the case for human - induced global warming was overstated and that natural climate variability could explain things just as easilIn 1990, two years after NASA scientist James E. Hansen issued his now famous warning about climate change during a congressional hearing, Lindzen started taking a publicly contrarian stance when he challenged then - senator Gore by suggesting in the Bulletin of the American Meteorological Society that the case for human - induced global warming was overstated and that natural climate variability could explain things just as easilin the Bulletin of the American Meteorological Society that the case for human - induced global warming was overstated and that natural climate variability could explain things just as easily.
Your comment about natural variability being such a «wild card» sound much more to belong in the white than in the red box though, so maybe I'm interpreting the flag numbers different than you?
I would like to see a switch in climate science funding into, if you like, measuring natural variability, or at least not assuming anything about human activity.
If you selectively read only the literature about the role of natural variability in climate, then your personal knowledge will lead to a flag with a large green portion (which seems to be where most of the commenters at WUWT are).
Until about 1850, there was some natural variability, as can be seen in coralline sponges (following the changes in the upper ocean layer) and ice cores (for the atmosphere).
I'd be especially interested in hearing what you believe an increased role of natural variability in the 20th century record implies about climate sensitivity as well as the behavior of the anthropogenic signal «beneath» it.
Regarding the 20th C warming, you put 28 % in natural variability based on the statement by the IPCC, but the statement says nothing about natural variability.
««Climate model simulations that consider only natural solar variability and volcanic aerosols since 1750 — omitting observed increases in greenhouse gases — are able to fit the observations of global temperatures only up until about 1950.»
You have not cited a third possibility (out of the infinite range of possibilities), no climate change associated with CO2 (due to, for example, cloud cover providing negative feedback), with current increase due to natural variability; or how about possibility four, that increase in CO2 concentrations are caused by the temperature rise, which is in turn caused by (for example) increased solar activity resulting in increased biomass activity etc. etc..
However, there is not compelling evidence that anthropogenic CO2 was sufficient to influence Earth's temperatures prior to 1950, i.e. «Climate model simulations that consider only natural solar variability and volcanic aerosols since 1750 — omitting observed increases in greenhouse gases — are able to fit the observations of global temperatures only up until about 1950.»
The disagreement was always about the scope and depth of natural variability, on the point where data adjustments become statistical manipulations, on gaps and uncertainties in data, on the proper use and limitations of climate models and on chaos in climate and models.
Yes and the real point about the inaccuracy of the GCMs is that natural + unconsidered variability in the outcome is so great and of such long time scale as to overstep the human time frame.
Meanwhile in the 1st Assessment Report, the authors were unsure whether the reported global warming was due to human activity, or simply due to natural variability, i.e., they felt it was «about as likely as not» to be man - made global warming, which is roughly equivalent to a score of 5.
If you can look past that one sentence, there's a lot in there about the global effects of natural variability, uncertainties in the surface data and so on.
Now you have talked about 4 years weather data having a meaning (0.25 degree climb in GAT) whereas we all know that natural variability on a seasonal basis at least in Australia can be around 10 degrees C and on a daily basis something around the same as well.
«Causes of differences in model and satellite tropospheric warming rates» «Comparing tropospheric warming in climate models and satellite data» «Robust comparison of climate models with observations using blended land air and ocean sea surface temperatures» «Coverage bias in the HadCRUT4 temperature series and its impact on recent temperature trends» «Reconciling warming trends» «Natural variability, radiative forcing and climate response in the recent hiatus reconciled» «Reconciling controversies about the «global warming hiatus»»
@PD: we all know that natural variability on a seasonal basis at least in Australia can be around 10 degrees C... My feeling is that) 0.25 degrees C is too small amount to be concerned about given the spread of natural variability.
Presumably Jim in the good old days we didn't have to worry about natural variability because temps were going up nicely and we were getting the result we wanted.
Irrespective of what one thinks about aerosol forcing, it would be hard to argue that the rate of net forcing increase and / or over-all radiative imbalance has actually dropped markedly in recent years, so any change in net heat uptake can only be reasonably attributed to a bit of natural variability or observational uncertainty.
Natural variability in the N.H. during last 130 years accounts for about 0.75 C, which is half of 1.5 C that is attributed to the GHG by the BEST report.
I don't consider myself to be an expert by any means but in the few years I have been taking an interest in the subject of climate change I have tried to educate myself as much as possible about the various scientific arguments surrounding the subject, and one thing that has constantly been impressed upon my mind is that when there is a long term trend caused by increasing GHG levels there will periods when it is masked (or accentuated) by short term natural variability.
However, there remains uncertainty in the rate of sea ice loss, with the models that most accurately project historical sea ice trends currently suggesting nearly ice - free conditions sometime between 2021 and 2043 (median 2035).12 Uncertainty across all models stems from a combination of large differences in projections among different climate models, natural climate variability, and uncertainty about future rates of fossil fuel emissions.