Sentences with phrase «estimating equilibrium sensitivity»

Not exact matches

The Hansen et al study (2004) on target atmospheric CO2 and climate sensitivity is quite clear on this topic: equilibrium responses would double the GCM - based estimates, with very little to be said about transient effects.

Where (equilibrium / effective) climate sensitivity (S) is the only parameter being estimated, and the estimation method works directly from the observed variables (e.g., by regression, as in Forster and Gregory, 2006, or mean estimation, as in Gregory et al, 2002) over the instrumental period, then the JP for S will be almost of the form 1 / S ^ 2.

Given that it doesn't matter much which forcing is changing, sensitivity can be assessed from any particular period in the past where the changes in forcing are known and the corresponding equilibrium temperature change can be estimated.

Inverse estimates of aerosol forcing from detection and attribution studies and studies estimating equilibrium climate sensitivity (see Section 9.6 and Table 9.3 for details on studies).

Given that it doesn't matter much which forcing is changing, sensitivity can be assessed from any particular period in the past where the changes in forcing are known and the corresponding equilibrium temperature change can be estimated.

You can not use equilibrium climate sensitivity to estimate the response to an 11 year periodic forcing — precisely because it is not in equilibirum!

captdallas2 @ 130 — To become more impressed by the estimate of about 3 K for Charney equilibrium climate sensitivity, read papers by Annan & Hargreaves.

Your attempt to estimate equilibrium climate sensitivity from the 20th C won't work because a) the forcings are not that well known (so the error in your estimate is large), b) the climate is not in equilibrium — you need to account for the uptake of heat in the ocean at least.

I didn't know that data since 1850 as summarized is essentially useless for estimating climate sensitivity given that the Earth's radiative heat exchange is not in equilibrium over that period.

Maybe the word «equilibrium» should be omitted from all climate sensitivity estimates, from the shortest term values (TCR) to the longest and most comprehensive (Earth System), since all the different forms of sensitivity estimation seem, in my view, to be looking at somewhat different phenomena and should not necessarily yield the same values.

Regarding ECS («equilibrium climate sensitivity»), I think there are difficulties estimating anything truly resembling a Charney - type ECS from data involving OHC uptake and forcing estimates, because these estimates are fraught with so many uncertainties, and because the values that are calculated, even if accurate, bear an uncertain relationship to how the climate would behave at equilibrium.

Hegerl et al (2006) for example used comparisons during the pre-industrial of EBM simulations and proxy temperature reconstructions based entirely or partially on tree - ring data to estimate the equilibrium 2xCO2 climate sensitivity, arguing for a substantially lower 5 % -95 % range of 1.5 — 6.2 C than found in several previous studies.

Even the conventional notion of ECS involving the short - term (Charney) feedbacks doesn't represent an equilibrium result, which is better represented by «Earth System Sensitivity» estimates.

Is there some simple intuitive explanation of how this pipeline warming is estimated with respect to an equilibrium climate sensitivity at a doubling of CO2 equivalent (thus including methane, ozone, aerosols, CFCs...)?

But 3,2 °C is the best estimate for equilibrium climate sensitivity (that is when the runs of models consider all the feedbacks).

The 2,1 - 4,4 °C range of IPCC 2007 (with 3 °C as best estimate) is equilibrium (long term) sensitivity.

In particular, equilibrium climate sensitivity (S), effective vertical deep ocean diffusivity (Kv) and total aerosol forcing (Faer) have been estimated in this way.

New, relevant, readily available, and influential science on a topic considered to be a «key factor» in the determination of the SCC — the distribution of the estimated value of the equilibrium climate sensitivity (ECS)-- was not included in the 2013 SCC update used in the final rulemaking.

In this work the equilibrium climate sensitivity (ECS) is estimated based on observed near - surface temperature change from the instrumental record, changes in ocean heat content and detailed RF time series.

(ppm) Year of Peak Emissions Percent Change in global emissions Global average temperature increase above pre-industrial at equilibrium, using «best estimate» climate sensitivity CO 2 concentration at stabilization (2010 = 388 ppm) CO 2 - eq.

This Nature Climate Change paper concluded, based purely on simulations by the GISS - E2 - R climate model, that estimates of the transient climate response (TCR) and equilibrium climate sensitivity (ECS) based on observations over the historical period (~ 1850 to recent times) were biased low.

To translate this into 2xCO2 temperature impact (equilibrium climate sensitivity) means that this would be around 0.6 deg C including all feedbacks, compared to the Myhre et al. estimate before feedbacks of around 1.0 degC and the IPCC mid-range estimate including all feedbacks of 3.2 degC.

I estimate dT increased from 1980 to 2010 by about 0.4 K. Given equilibrium climate sensitivity of 0.75 K / Wm2, the amount of forcing neutralised by said dT is; 0.4 * 0.75 = 0.3 W / m2.

If we assume the most likely climate sensitivity estimate is correct (3 °C for the equivalent of a doubling of atmospheric CO2), the equilibrium climate sensitivity parameter is 0.8.

An updated estimate of the equilibrium climate sensitivity distribution (ECS)-- a measure of CO2's temperature impact — reduces the 2020 estimate of SCC by more than 40 percent; and

[7] Each individual estimate of the SCC is the realization of a Monte Carlo simulation based on a draw from an equilibrium climate sensitivity distribution to model the impact of CO2 emissions on temperature.

Furthermore, Gillett et al.'s central estimate of the transient response, 1.3 °C, very closely matches the 1.2 °C and 1.5 °C alternative IPCC estimates of warming per 1,000 GtC after 1,000 y from the end of emissions, assuming a midrange equilibrium climate sensitivity of 3 °C to the doubling of preindustrial carbon levels (6).

Here we present a stricter approach, to improve intercomparison of palaeoclimate sensitivity estimates in a manner compatible with equilibrium projections for futureclimate change.

Assuming the same climate sensitivity, Lindzen's estimate of a 2.5 °C drop for a -30 W / m2 forcing would imply that currently doubling CO2 would warm the planet by only a third of a degree at equilibrium, which is well outside the bounds of IPCC estimates and even very low by most skeptical standards.

Many palaeoclimate studies have quantified pre-anthropogenic climate change to calculate climate sensitivity (equilibrium temperature change in response to radiative forcing change), but a lack of consistent methodologies produces awide range of estimates and hinders comparability of results.

It also states, «No best estimate for equilibrium climate sensitivity can now be given because of a lack of agreement on values across assessed lines of evidence and studies.»

The three successive IPCC reports (1991 [2], 1996, and 2001 [3]-RRB- concentrated therefore, in addition to estimates of equilibrium sensitivity, on estimates of climate change over the 21st century, based on several scenarios of CO2 increase over this time interval, and using up to 18 general circulation models (GCMs) in the fourth IPCC Assessment Report (AR4)[4].

Note 16 «No best estimate for equilibrium climate sensitivity can now be given because of a lack of agreement on values across assessed lines of evidence and studies.»

You compare estimates (2xCO2) «equilibrium climate sensitivity» with measurements of the mass of the moon.

And that says nothing about the fact that the Equilibrium Climate Sensitivity is supposed to reflect the rise in temperature following an increase in atmospheric CO2, but what is estimated is the rise in temperature PRECEEDING an increase in atmospheric CO2.

The solid evidence lies in the fact that estimates of the so - called Equilibrium Climate Sensitivity are less than the minimum set for it by the climatologists.

A.) If I wanted to get a rough estimate of the equilibrium warming response to a tripling of the preindustrial atmospheric concentration of CO2eq (so 3 x 280 CO2eq ppm), I would just take my best sensitivity - per - doubling estimate on the bottom bar and multiply it by 1.5?

Due to computational constraints, the equilibrium climate sensitivity in a climate model is usually estimated by running an atmospheric general circulation model coupled to a mixed - layer ocean model, because equilibrium climate sensitivity is largely determined by atmospheric processes.

Climate sensitivities estimated from recent observations will therefore be biased low in comparison with CO2 - only simulations owing to an accident of history: when the efficacies of the forcings in the recent historical record are properly taken into account, estimates of [Transient Climate Respons — TCR] and [Equilibrium Climate Sensitivity — ECS] must be revised upwards.

But, as we have discussed previously, the new, lower estimate of the equilibrium climate sensitivity is just one of several key variables to which the SCC is very sensitive.

The IPCC gets its 2 - 4.5 C climate sensitivity range from Table 8.2 of the AR4, which lists 19 climate model - derived equilibrium sensitivity estimates that have a mean of 3.2 C and a standard deviation of 0.7 C.

The Lewis and Curry paper said the best estimate for equilibrium climate sensitivity — the change in global mean surface temperature at equilibrium that is caused by a doubling of the atmospheric CO2 concentration — was 1.64 degrees.

«The likely range for equilibrium climate sensitivity was estimated in the TAR to be 1.5 °C to 4.5 °C.»

The concept of abrupt climate change does not figure into any estimate of equilibrium sensitivity that I am aware of.

As a result, the Cess climate sensitivity parameter should not be interpreted at its face value for estimates of model equilibrium climate sensitivity.

The fact that the estimates based on the instrumental period tend to peak low has probably more to do with the fact that the climate has not been in equilibrium during that entire instrumental period and so therefore converting the sensitivity computed into an equilibrium climate sensitivity (ECS), which is what is being discussed, requires some guesswork (and, dare I say it — modelling).

As for the LGM, equilibrium climate sensitivity estimates depend strongly on the temperature data used.

Along with the corrected value of F2xCO2 being higher than the one used in the paper, and the correct comparison being with the model's effective climate sensitivity of ~ 2.0 C, this results in a higher estimate of equilibrium efficacy from Historical total forcing.

Research by Schmittner et al. (2011) and Annan and Hargreaves (2012) found most likely equilibrium sensitivity values close to 2.5 °C based on LGM changes, whereas as noted above, Hansen et al. (2008) estimated 3 ± 1 °C sensitivity based on the LGM.

The paper's results show the best (median) estimates and «likely» (17 — 83 % probability) ranges for equilibrium / effective climate sensitivity (ECS) and transient climate response (TCR) given in the Lewis & Crok report to have been conservative.