Sentences with phrase «equilibrium climate sensitivity from»

[17] Cox, P. M., C. Huntingford, and M. S. Williamson, 2018: Emergent constraint on equilibrium climate sensitivity from global temperature variability.

Loehle estimated the equilibrium climate sensitivity from his transient calculation based on the average transient: equilibrium ratio projected by the collection of climate models used in the IPCC's most recent Assessment Report.

My first thought on reading the FG paper was, how well could they derive equilibrium climate sensitivity from such a short time period (15 years)?

In the Working Group 1: The Physical Science Basis Report of AR4 («AR4: WG1»), various studies deriving estimates of equilibrium climate sensitivity from observational data are cited, and a comparison of the results of many of these studies is shown in Figure 9.20, reproduced below.

«Climate sensitivity estimates are greatly impacted by such variability especially when the observed record is used to try to place limits on equilibrium climate sensitivity [Otto et al., 2013], and simply using the ORAS - 4 estimates of OHC changes in the 2000s instead of those used by Otto... changes their computed equilibrium climate sensitivity from 2.0 °C to 2.5 °C, for instance.

My comments here relate specifically to determination of equilibrium climate sensitivity from climate models.

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.

Not exact matches

Does it mean that transient climate response (as expressed by ice sheet or see - ice melting among other events) to GHGs is not so far from equilibrium climate sensitivity?

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.

From the article: «The most likely value of equilibrium climate sensitivity based on the energy budget of the most recent decade is 2.0 °C, with a 5 — 95 % confidence interval of 1.2 — 3.9 °C»

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).

Using the middle of the range of climate sensitivities of 3 oC of warming at equilibrium per doubling of [CO2], a rise of [CO2] from 280 - 310 ppm should give 0.44 oC at equilibrium.

A few things are unequivocal, perhaps (doubling from the present concentration of CO2 will take 140 years [give or take]; the idea that the changes in climate since 1880 have been in the aggregate beneficial; it takes more energy to vaporize a kg of water than to raise its temperature by 1K; ignoring the energy cost of water and latent heat transport [in the hydrologic cycle] leads to equilibrium calculations overestimating the climate sensitivity), but most are propositions that I think need more research, but can't be refuted on present evidence.

So the marked early 20th century warming was likely a mixture of recovery from volcanic forcing and accumulated (but masked) greenhouse forcing [the 1880 - 1940 [CO2] rise from ~ 290 — ~ 309 ppm was quite significant (equivalent to nearly 0.3 oC at equilibrium with a mid-range climate sensitivity)-RSB-.

The 100 % anthropogenic attribution from climate models is derived from climate models that have an average equilibrium climate sensitivity (ECS) around 3C.

We climatologists describe this in terms of the climate sensitivity, the warming that results in equilibrium from a doubling of CO2.

Aslo, regarding climate sensitivity a very key thing to remember, especially if sensitivity turns out to be on the high side, is that the «final» equilibrium temperature (Alexi's concerns about there being such a thing aside) calculated from climate sensitivity does not take into account carbon cycle feedbacks OR ice sheet changes.

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.

In this case the CO2 concentration is instantaneously quadrupled and kept constant for 150 years of simulation, and both equilibrium climate sensitivity and RF are diagnosed from a linear fit of perturbations in global mean surface temperature to the instantaneous radiative imbalance at the TOA.

What could hypothetically happen if a very large change in GHG amount / type is made, is that the forcing could increase beyond a point where it becomes saturated at the tropopause level at all wavelengths — what can happen then is that the equilibrium climate sensitivity to the nearly zero forcing from additional GHGs may approach infinity, because in equilibrium the tropopause has to shift upward enough to reach a level where there can be some net LW flux up through it.

Cox et al.'s calculations of the equilibrium climate sensitivity used a key metric which was derived from the Hasselmann model and assumed a constant C:.

Note that «equilibrium» in this thread — up through response 162 — was in terms of climate sensitivity, answering the question about where the «extra heat» comes from.

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.

Scientists often talk about it in terms of the equilibrium climate sensitivity (ECS), which is the long - term temperature increase that we expect from a permanent doubling of atmospheric CO2.

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.

[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).

From the forcing and the Climate Sensitivity Factor, the temperature impact of CO2 at equilibrium is easilly calculated.

Climate sensitivity is normally taken to mean the temperature increase (after equilibrium is attained) which would result from a doubling of CO2.

And the gut feeling by IPCC is everything from a walk in the park to catastrophe: «The equilibrium climate sensitivity quantifies the response of the climate system to constant radiative forcing on multi - century time scales.

[Equilibrium] climate sensitivity is defined as the increase in global mean surface temperature (GMST), once the ocean has reached equilibrium, resulting from a doubling of the equivalent atmospheric CO2 concentration, being the concentration of CO2 that would cause the same radiative forcing as the given mixture of CO2 and other forcing Equilibrium] climate sensitivity is defined as the increase in global mean surface temperature (GMST), once the ocean has reached equilibrium, resulting from a doubling of the equivalent atmospheric CO2 concentration, being the concentration of CO2 that would cause the same radiative forcing as the given mixture of CO2 and other forcing equilibrium, resulting from a doubling of the equivalent atmospheric CO2 concentration, being the concentration of CO2 that would cause the same radiative forcing as the given mixture of CO2 and other forcing components.

The net result is that the planet self controls, reducing CO2 climate sensitivity for purely radiative equilibrium from ~ 0.85 K to near zero.

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.

Our DOE Comment focuses entirely on the new science concerning the equilibrium climate sensitivity, that is, how much the earth's average surface temperature will increase from a doubling of the atmospheric carbon dioxide content.

«The Coupled Model Intercomparison Project Phase 5 (CMIP5) model spread in equilibrium climate sensitivity ranges from 2.1 °C to 4.7 °C and is very similar to the assessment in the AR4.

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.

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.

Third, our calculations are for a single fast - feedback equilibrium climate sensitivity, 3 °C for doubled CO2, which we infer from paleoclimate data.

The equilibrium climate sensitivity will be about 50 % greater than this due to the ocean acting as a heat sink, so the ECS will be about 3C, in line with the mean estimate from the models.

With the Greenland ice sheet melting like butter now and not 100 years from now as IPCC originally expected, the Equilibrium Climate Sensitivity measure and its inherent assumption that ice sheet and tundra response will be slow, seems to be shaping up as too conservative.

I agree that reduction in snow or ice cover resulting from warming constitutes a likely slow positive feedback, but its magnitude may be quite small, at least for the modest changes in surface temperature that can be expected to arise if sensitivity is in fact fairly low, so the Forster / Gregory 06 results may nevertheless be a close approximation to a measurement of equilibrium climate sensitivity.

In contrast, a probability density function over the equilibrium climate sensitivity conveys no information to a maker of public policy regarding the outcomes from his / her policy decisions.

Various paleoclimate - based equilibrium climate sensitivity estimates from a range of geologic time periods.

It follows from the above proof that the problem of determination of the prior and posterior probability density functions belonging to the equilibrium climate sensitivity lacks a solution.

''... had the IPCC FAR correctly projected the changes in atmospheric GHG from 1990 to 2011, their «best estimate» model with a 2.5 °C equilibrium climate sensitivity would have projected the ensuing global warming very accurately»

Because this is a fascinating subject, and equilibrium climate sensitivity (ECS) is contentious, I thought I'd summarize my impressions from the discussion so far.

«Results imply that global and regional warming rates depend sensitively on regional ocean processes setting the [ocean heat uptake] pattern, and that equilibrium climate sensitivity can not be reliably estimated from transient observations.»

And, if we accept the IPCC 2xCO2 climate sensitivity of 3.2 °C, this naturally occurring trend will limit the amount of theoretical equilibrium GH warming we can expect from today to 2100 at somewhere between 0.6 ° -1.5 °C.

The statement which was made regarding atmospheric cooling, is from NASA, and not Columbia University: «To quantify climate change, researchers need to know the Transient Climate Response (TCR) and Equilibrium Climate Sensitivity (ECS) ofclimate change, researchers need to know the Transient Climate Response (TCR) and Equilibrium Climate Sensitivity (ECS) ofClimate Response (TCR) and Equilibrium Climate Sensitivity (ECS) ofClimate Sensitivity (ECS) of Earth.