Sentences with phrase «what estimates of sensitivity»

I would be interested in what estimates of sensitivity result from using one or another of these approaches.

Not exact matches

Olson, R., et al. «What is the effect of unresolved internal climate variability on climate sensitivity estimates?.»

In this commentary, I will discuss the question «If somebody were to discover that climate variations in the past were stronger than previously thought, what would be the implications for estimates of climate sensitivity?»

«note that what is done with these estimates of climate sensitivity for LGM climate is to use the state of the climate already in place at the LGM — including the ice albedo.»

So, what's the current best estimate of the ocean temperature sensitivity?

I'm increasingly thinking that what we really need is an estimate of the sensitivity of the system to an injection of carbon dioxide including the feedback from the carbon cycle etc..

collectively explore reasonable bounds on estimates of climate sensitivities (TCR, ECS), i.e., what we might call extreme sensitivities in the sense that they are «more than likely» not to be exceeded.

Recommendation: The Secretary of Education should publish more detailed Income Driven Repayment plan cost information — beyond what is regularly provided through the President's budget — including items such as total estimated costs, sensitivity analysis results, key limitations, and expected forgiveness amounts.

On sensitivity positive and negative feedbacks: Since the temps are pushing the upper bounds of the estimated ranges, one could say reasonably that what we don't know has more in common with the speed of the feedbacks, not the question of CO2 sensitivity as you infer.

Gavin's explanation of sensitivity above is the first clear explanation I've ever seen, making the point about what is — and is not — included in the many attempts to come up with a sensitivity estimate.

[Response: I looked into what you could change in the model that would have done better (there is no such thing as a RIGHT / WRONG distinction — only gradations of skill), and I estimated that a model with a sensitivity of ~ 3 deg C / 2xCO2 give the observed forcings would have had higher skill.

Just to follow - up on John Finn's question (# 10), if one puts in a rough value for the emissivity of the earth (whatever that might be), so one is no longer assuming it is a perfect blackbody, then does the resulting estimate for climate sensitivity correspond to what one would expect in the absence of any feedback effects?

Would it not be more appropriate to rerun the models over the same time span that Hansen ran them, using current best estimates of parameters (such as sensitivity to CO2 doubling) and see what those predict?

One earlier comment tangentially alluded to this, but there are a lot of gaps that need to be filled in to say what such a result might mean for attempts at estimating climate sensitivity.

In this commentary, I will discuss the question «If somebody were to discover that climate variations in the past were stronger than previously thought, what would be the implications for estimates of climate sensitivity?»

What's new is that several recent papers have offered best estimates for climate sensitivity that are below four degrees Fahrenheit, rather than the previous best estimate of just above five degrees, and they have also suggested that the highest estimates are pretty implausible.

In fact, Cane et al (1997) argue that the tendency toward increased SST gradient is precisely what is seen if one uses a robust trend analysis to decrease sensitivity of the trend analysis to outliers such as the very large 1982/1983 El Nino event (this event, and the equally large 1997/1998 El Nino event, greatly influence the estimate of a weakening trend of the Walker circulation in Vecchi et al).

What is obvious is that including the data of the past few years pushes the estimates of climate sensitivity downward, because there was little warming over the past decade despite a larger greenhouse gas forcing.

What I still miss is, for climate sensitivity at 2xCO2 (540 ppm) we're discussing here, how you «jump» from a best estimate of 3 °C to 6 °C.

At the risk of repetition, let me reword what I believe is a major part of Jim Cripwell's source of skepticism regarding a significant «sensitivity» estimate.

Of course people are trying to poke holes in the «consensus» position, although I'm not sure what the consensus is since estimates of climate sensitivity have a very wide rangOf course people are trying to poke holes in the «consensus» position, although I'm not sure what the consensus is since estimates of climate sensitivity have a very wide rangof climate sensitivity have a very wide range.

Using models that don't do what you need to say sensitivity is even higher than models estimate, so that warmunists can ignore all the observational effective sensitivity estimates, smacks of illogical desperation.

What would happen if an unbiased assessment of climate sensitivity were 1.5 - 3.0 degK with a best estimate of 2.0 degK?

I have concentrated on the Bayesian inference involved in such studies, since they seem to me in many cases to use inappropriate prior distributions that heavily fatten the upper tail of the estimated PDF for S. I may write a future post concerning that issue, but in this post I want to deal with more basic statistical issues arising in what is, probably, the most important of the Bayesian studies whose PDFs for climate sensitivity were featured in AR4.

What Willis seems to do is fit to the known temperature anomalies using the now «known» changes in forcing and hence gets an estimate for lambda and then uses this to get a climate sensitivity in K. However, climate sensitivity is defined according to the change in forcing due to a doubling of CO2.

Dickey estimate a sensitivity of -0.6 to -0.7 C / millisec and that's close to what I get in the multi-regression fit.

If you know of anyone who has used the 3D model described in the paper I linked above (or a more complex one) to estimate this climate sensitivity parameter, please just share the link so I can see what they do and how they derive it.

As an attempt at that reasonable discussion, to what extent are the marginally lower estimates for sensitivity cancelled out by evidence of more severe impacts from a given level of warming?

It appears that the Hansen Scenario B performed fairly well, with an overestimated trend consistent with its estimate of climate sensitivity at what is now considered to be toward the high end of the likely range (although of course, Hansen continues to estimate climate sensitivity at higher levels than most other observers).

Now tell us all cousin IT, why use the RCP8.5 and what exactly is your informed estimate of «sensitivity»?

Based on the principles of radiative physics and reasonable estimates of feedbacks and climate sensitivity, I would say that any current oscillations beyond those we already know can't be strong so strong that they leave little or no room for what anthropogenic emissions are contributing to the temperature trend.

First, instead of using an ensemble of models to calculate the 66th percentile of runs that result in 1.5 C warming, they use a range of possible climate sensitivity values that ends up providing a more conservative estimate of what it would take to exceed 1.5 C.

What we have seen is also clear evidence for significant natural variability, which makes it difficult to estimate accurately the strength of AGW (or the climate sensitivity or transient climate response).

Although below the model ECS of 2.3 C, that is very close to the GISS - E2 - R effective climate sensitivity of ~ 2 C, which is what this method would estimate if the forcing were purely from CO2.

If you want a precise estimate of the change in sensitivity from what you would consider a «trusted source», you are own your own.

What he writes now is very well in line of the reasoning he presented in the 2009 paper with Hargreaves: On the generation and interpretation of probabilistic estimates of climate sensitivity.

I again used the variance in our estimate of climate sensitivity as an indicator of uncertainty — if you are unclear about what that means, refresh your memory here.

What we have seen is not in contradiction with the scientific understanding that's represented in the IPCC reports, but it does certainly give some support for the lower estimates for the strength of the trend or equivalently for the transient climate sensitivity.

Sensitivity equals dT / dF is only valid for an absolute temperature and absolute forcing over a small range of change and since the current «state of the artistry» «surface temperature average» requires using anomaly from very cold locations with very little energy per degree of anomaly, what «surface» is averaged impacts the estimate of «sensitivSensitivity equals dT / dF is only valid for an absolute temperature and absolute forcing over a small range of change and since the current «state of the artistry» «surface temperature average» requires using anomaly from very cold locations with very little energy per degree of anomaly, what «surface» is averaged impacts the estimate of «sensitivitysensitivity».

So, if we can never measure the climate sensitivity, we will always will be left with hypothetical and theoretical estimates of what this value might be.

I also want to try to get sensitivity analyses done so I can understand what are the most significant factors for estimating net costs and benefits of advocated mitigation policies.

That a robust behaviour in models of apparent (effective) climate sensitivity being lower in the early years after a forcing is imposed than subsequently, rather than remaining constant, requires multiplying estimates of climate sensitivity by a further factor of ~ 1.25 in order to convert what they actually estimate (effective climate sensitivity) to ECS.

James I very largely agree with what you say, but may I respond on some of your comments relating to my recent energy - balance based climate sensitivity estimate?

The absolute truth will not be known for a century, if ever, but we may get some good indications if the coming decades see stabilization of temperatures despite what seems inevitable CO2 increases, which will argue for a much lower level of CO2 sensitivity than estimated by the official climate Team.

I have written extensively on the shortcomings of the Administration's determination of the SCC (for example, http://www.cato.org/publications/commentary/obamas-social-cost-carbon-odds-science) and the folks at the Heritage Foundation just yesterday released a report looking at what would happen in DICE model if recent estimates of the equilibrium climate sensitivity were used in place of the (outdated) ones used by the Administration.

What this means: ECS — «equilibrium climate sensitivity» — is an estimate of how much the world will warm every time carbon dioxide levels double.

«The «current method» (or «definition», if you wish) of estimating climate sensitivity is by taking the ratio of what we estimate is (or in the case of centuries past, was) the equilibrium temperature response and divide it by what we think is (or in the case of centuries past, was) the net climate forcing.»

collectively explore reasonable bounds on estimates of climate sensitivities (TCR, ECS), i.e., what we might call extreme sensitivities in the sense that they are «more than likely» not to be exceeded.

It gives a TCR range of 1.0C - 2.5 C and a transient response to cumulative CO2 emissions of 0.8C - 2.5 C. Again, no best estimates, so they really don't know what climate sensitivity might actually be; could be low, could be high.

What this paper attempts to do is point the way to a simple, physically sound approach to reducing uncertainty and establishing estimates of climate sensitivity that are focused and testable.