Sentences with phrase «based equilibrium climate»

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

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.

The «equilibrium» sensitivity of the global surface temperature to solar irradiance variations, which is calculated simply by dividing the absolute temperature on the earth's surface (288K) by the solar constant (1365Wm - 2), is based on the assumption that the climate response is linear in the whole temperature band starting at the zero point.

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»

They conclude, based on study of CMIP5 model output, that equilibrium climate sensitivity (ECS) is not a fixed quantity — as temperatures increase, the response is nonlinear, with a smaller effective ECS in the first decades of the experiments, increasing over time.

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.

ECS is a bogus concept, based on the late Cenozoic cooling following the closing of Tethys and the isthmus of Panama, the world keeps getting colder and colder, so we have not reached the bottom yet, indicating that there is no equilibrium, just a pathway to the next bumper that bounces the climate the other way.

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.

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 biasClimate 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 biasclimate 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 biasclimate response (TCR) and equilibrium climate sensitivity (ECS) based on observations over the historical period (~ 1850 to recent times) were biasclimate sensitivity (ECS) based on observations over the historical period (~ 1850 to recent times) were biased low.

The notion of the Earth as a collection of systems in fragile equilibrium on which society is closely dependent, for instance, forms the basis of a great deal of policy as well as research into «climate impacts».

[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.

When I rephrased my question and gave some background to my reason for asking it, you went way outside your area of expertise and turned to stating your opinions (based on you ideological beliefs) about how much your tool says the planet will warm by 2100 (4.4 C you said based on 3.2 C equilibrium climate sensitivity).

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].

[¶]... Basing our assessment on a combination of several independent lines of evidence, as summarised in Box 10.2 Figures 1 and 2, including observed climate change and the strength of known feedbacks simulated in GCMs, we conclude that the global mean equilibrium warming for doubling CO2, or «equilibrium climate sensitivity», is likely to lie in the range 2 °C to 4.5 °C, with a most likely value of about 3 °C.

In contrast to climate models, which are biogeophysically - based systems models that incorporate time - delayed feedbacks and non-linear dynamics, the economic and demographic models that underpin the Intergovernmental Panel on Climate Change (IPCC) are price - based equilibrium climate models, which are biogeophysically - based systems models that incorporate time - delayed feedbacks and non-linear dynamics, the economic and demographic models that underpin the Intergovernmental Panel on Climate Change (IPCC) are price - based equilibrium Climate Change (IPCC) are price - based equilibrium models.

I asked you yesterday whether you were aware that two of the climate sensitivity PDFs in Figure 9.20 of the IPCC AR4 WG1 report were not in fact based on a uniform prior in equilibrium climate sensitivity (ECS or S), despite it being stated in Table 9.3 that they were so based.

Equilibrium climate sensitivity is likely to be in the range 2 °C to 4.5 °C with a most likely value of about 3 °C, based upon multiple observational and modelling constraints.

Equilibrium climate sensitivity is likely between 1.5 K to 4.5 K, with that range to likely increase to 2K to 4.5 K now that the errors in the energy - budget - model - based approaches (used by Lewis, Curry, and others) have been identified.

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).

manacker / max You write «Past predictions of 2xCO2 climate sensitivity at equilibrium (ECS) have been made based on model simulations, rather than on analyses of real - time data».

Past predictions of 2xCO2 climate sensitivity at equilibrium (ECS) have been made based on model simulations, rather than on analyses of real - time data.

Show me the empirical data, based on real - time physical observations or reproducible experimentation (NOT climate model runs), which support the premise that GH warming requires decades or even centuries to reach «equilibrium».

For an equilibrium climate, global mean outgoing longwave radiation (OLR) necessarily balances the incoming absorbed solar radiation (ASR), but with redistributions of energy within the climate system to enable this to happen on a global basis.

«The Earth's climate system is highly nonlinear: inputs and outputs are not proportional, change is often episodic and abrupt, rather than slow and gradual, and multiple equilibria are the norm... there is a relatively poor understanding of the different types of nonlinearities, how they manifest under various conditions, and whether they reflect a climate system driven by astronomical forcings, by internal feedbacks, or by a combination of both... [We] suggest a robust alternative to prediction that is based on using integrated assessments within the framework of vulnerability studies... It is imperative that the Earth's climate system research community embraces this nonlinear paradigm if we are to move forward in the assessment of the human influence on climate.»

Our calculated global warming as a function of CO2 amount is based on equilibrium climate sensitivity 3 °C for doubled CO2.

The 95 percent confidence range in this study was between about 1 and 7 °C equilibrium sensitivity, so very low and very high climate sensitivities could not be ruled out, but are relatively unlikely, based on the historical record.

Nearly all of the equations in physics are approximations, and those used in climate science that I have seen to date are all based on some simplifications (equilibrium, for example; or ignoring the fact that 22 % if incoming TOA radiation is absorbed in the upper atmosphere.)

Therefore, estimating equilibrium climate sensitivity based on measurements of a climate that's out of equilibrium requires making some significant assumptions, for example that feedbacks will remain constant over time.

But, nevertheless, Lewis and Curry have generated a very robust observation - based estimate of the equilibrium climate sensitivity.

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.

Similarly, the climate scenarios were based on 2xCO2 equilibrium GCM projections from three models, where the radiative forcing of climate was interpreted as the combined concentrations of CO2 (555 ppm) and other greenhouse gases (contributing about 15 % of the change in forcing) equivalent to a doubling of CO2, assumed to occur in about 2060.

Energy budget estimates of equilibrium climate sensitivity (ECS) and transient climate response (TCR) are derived based on the best estimates and uncertainty ranges for forcing provided in the IPCC Fifth Assessment Scientific Report (AR5).

On a global basis, the Julia implementation of FUND3.9 give the following impacts per GDP by component assuming a 3 °C equilibrium climate sensitivity (ECS);

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.

Spencer and Braswell freely admit that using their simple model is just the first step in a complicated diagnosis, but also point out that the results from simple models provide insight that should help guide the development of more complex models, and ultimately could help unravel some of the mystery as to why full climate models produce high estimates of the earth's equilibrium climate sensitivity, while estimates based in real - world observations are much lower.

The TSD purports to rely on IPCC work as a basis for a supposed «sensitivity» of climate to increasing atmospheric C02, but fails to mention that the most recent IPCC report completely undermines any basis for determining climate sensitivity with the following statement: «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.»

Recently there have been some studies and comments by a few climate scientists that based on the slowed global surface warming over the past decade, estimates of the Earth's overall equilibrium climate sensitivity (the total amount of global surface warming in response to the increased greenhouse effect from a doubling of atmospheric CO2, including amplifying and dampening feedbacks) may be a bit too high.

They conclude, based on study of CMIP5 model output, that equilibrium climate sensitivity (ECS) is not a fixed quantity — as temperatures increase, the response is nonlinear, with a smaller effective ECS in the first decades of the experiments, increasing over time.

Estimates based on recent observations can only be of effective, not equilibrium, climate sensitivity, since the climate system has not reached equilibrium.

Nic Lewis in the post at BishopHill does a very nice empirically based sensitivity analysis following the general methodology of the Gregory et al (2002) heat balance change derived value of the equilibrium climate sensitivity, determining a value of ECS of 1.6 - 1.7 C.

If there is good reason to suppose that the paradigm is failing or about to fail, as there is with the current climate paradigm based on GCM models and a perturbed equilibrium model of response to changes in pCO2 or other greenhouse gases, then it becomes incumbent on corporate management to assure that plausible alternatives are investigated to the best of their judgment and ability, including financial.

When zero - intercept regressions are used for estimation, the transient efficacy of Historical iRF is then 1.02, and the equilibrium efficacy is also 1.02 (1.09 with ΔQ divided by 0.86), based on an effective climate sensitivity of 2.0 °C for the model.

Bernard, A.L., and M. Vielle, 2003: Measuring the welfare cost of climate change policies: A comparative assessment based on the computable general - equilibrium Model GEMINI - E3.

Hot off the press, in yesterday's Journal of Climate, Nic Lewis and Judith Curry have re-calculated the equilibrium climate sensitivity (ECS) based upon the historical uptake of heat into the ocean and human emissions of greenhouse gases and aeClimate, Nic Lewis and Judith Curry have re-calculated the equilibrium climate sensitivity (ECS) based upon the historical uptake of heat into the ocean and human emissions of greenhouse gases and aeclimate sensitivity (ECS) based upon the historical uptake of heat into the ocean and human emissions of greenhouse gases and aerosols.

In short the PETM seems to contradict the AGW point of equilibrium climate sensitivity based on a new level of forcing through CO2 increase..