Sentences with phrase «own equilibrium climate»

Scientists call this responsiveness «equilibrium climate sensitivity» (ECS).

A leaked draft copy of the Intergovernmental Panel on Climate Change's fifth assessment report (AR5) surfaced earlier this summer and triggered a small tempest among climate bloggers, scientists and skeptics over revelations that a key metric, called the «Equilibrium Climate Sensitivity» (ECS), had been revised downward.

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?

Specifically, the draft report says that «equilibrium climate sensitivity» (ECS)-- eventual warming induced by a doubling of carbon dioxide in the atmosphere, which takes hundreds of years to occur — is «extremely likely» to be above 1 degree Celsius (1.8 degrees Fahrenheit), «likely» to be above 1.5 degrees Celsius (2.4 degrees Fahrenheit) and «very likely» to be below 6 degrees Celsius (10.8 Fahrenheit).

The transient and equilibrium climate response to rapid summertime sea ice loss in CCSM4.

We have often made the case here that equilibrium climate sensitivity is most likely to be around 0.75 + / - 0.25 C / (W / m2)(corresponding to about a 3 °C rise for a doubling of CO2).

Beyond equilibrium climate sensitivity -LSB-...] Newer metrics relating global warming directly to the total emitted CO2 show that in order to keep warming to within 2 °C, future CO2 emissions have to remain strongly limited, irrespective of climate sensitivity being at the high or low end.»

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»

Forecast temperature trends for time scales of a few decades or less are not very sensitive to the model's equilibrium climate sensitivity (reference provided).

The real «equilibrium climate sensitivity,» which is the amount of global warming to be expected for a doubling of atmospheric CO2, is likely to be about 1 °C, some three times smaller than most models assumed.

Blanchet, and M. Lazare, 1992: The Canadian Climate Centre second - generation general circulation model and its equilibrium climate.

Here's an interesting paper that is referenced in some of the listed publications: Meraner et al. 2013, Robust increase in equilibrium climate sensitivity under global warming, GRL https://hal.inria.fr/hal-01099395/document

There have been quite a number of papers published in recent years concerning «emergent constraints» on equilibrium climate sensitivity (ECS) in comprehensive global climate models (GCMs), of both the current (CMIP5) and previous (CMIP3) generations.

In Part 1 of this article the nature and validity of emergent constraints [1] on equilibrium climate sensitivity (ECS) in GCMs were discussed, drawing mainly on the analysis and assessment of 19 such constraints in Caldwell et al. (2018), [2] who concluded that only four of them were credible.

Yes, the discussion above is about equilibrium climate sensitivity and by picking 2100 (or 2011) we'll be measuring the transient climate sensitivity.

And further, in stating the year 2100 values, you are mixing up transient with equilibrium climate sensitivity.

[Response: Check out the transient vs. equilibrium climate discussion in our National Research Council report, «Climate Stabilization Targets» (free from the NAS web site.

In Part 1 of this article the nature and validity of emergent constraints [i] on equilibrium climate sensitivity (ECS) in GCMs were discussed, drawing mainly on the analysis and assessment of 19 such constraints in Caldwell et al (2018; henceforth Caldwell), [ii] who concluded that only four of them were credible.

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.

Then on page 9.5 we read «There is very high confidence that the primary factor contributing to the spread in equilibrium climate sensitivity continues to be the cloud feedback.

Virtually all equilibrium climate models simulate a strong decrease in the area of sea ice [18].

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).

First let's define the «equilibrium climate sensitivity» as the «equilibrium change in global mean surface temperature following a doubling of the atmospheric (equivalent) CO2 concentration.

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

Elevated trace GHG concentrations contributed an estimated positive forcing of approximately 1.7 — 2.3 W m - 2 (Table S5) in addition to that of CO2 and produced equilibrium climate system responses resulting in widespread significant warming, especially in the high latitudes (Figs. 3 and 4).

Geoff any forcing is positive feedback and there are many of those loops at work now working against climate homeostasis and the more from equilibrium climate becomes more additional + ve loops just join the fray.

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

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.

To get an idea of why this is, we can start with the simplest 1D energy balance equilibrium climate model:

Setting both aside and just considering equilibrium climate, there can still be hysteresis.

It gets tricky now because the equilibrium climate sensitivity requires a timescale to be defined — barring large hysteresis, it isn't so large going out many millions of years (weathering feedback); there will be a time scale of maximum sensitivity.

The notion that the response to Pinatubo can determine equilibrium climate sensitivity is rather odd, and is not supported by evidence.

Nevertheless, climate sensitivity is part of the puzzle, and it particularly matters if you are interested in stabilisation scenarios, since it indicates what a particular equilibrium CO2 level will mean for equilibrium climate.

You can estimate how close to equilibrium the climate must be over such a time period assuming for instance that all the energy imbalance goes to melting ice: an imbalance of say 0.1 W / m2 would over 2000 years melts / grows approx 18m of ice.

At equilibrium, T» is constant and equal to Teq», so G * Teq» = For», thus Teq» = For» / G, so that equilibrium climate sensitivity = 1 / G (perhaps G could be called the climate «insensitivity»).

The true equilibrium climate sensitivity for the climate models used in this demonstration is in the range 2.1 — 4.4, and the transient climate sensitivity is 1.2 — 2.6 (IPCC AR5, Table 8.2).

Annan said equilibrium climate sensitivity is unlikely to be higher than 4.5 °C — there are few if any mainstream climate scientists who would disagree with this.

Nonetheless, there is a tendency for similar equilibrium climate sensitivity ECS, especially using a Charney ECS defined as equilibrium global time average surface temperature change per unit tropopause - level forcing with stratospheric adjustment, for different types of forcings (CO2, CH4, solar) if the forcings are not too idiosyncratic.

DDS 1: «The claim of reduced uncertainty for equilibrium climate sensitivity is premature» This is what many climate skeptics have been saying for years and they have been called deniers for their efforts.

The forcing and feedback (including the vertical temperature profile feedback) will be different in complimentary ways to result in the same magnitude of shift in equilibrium climate.

Equilibrium climate sensitivity describes how much the planet will warm if carbon dioxide levels were to double, and the Earth goes on to cope and stabilize to the new atmosphere.

That forcing is just under 4W / m ^ 2, so put differently, equilibrium climate sensitivity is the equilibrium expected surface warming for a radiative forcing of 1W / m ^ 2, divided by 4.

In the approximation of zero non-radiative vertical heat fluxes above the tropopause, net upward LW flux = net downward SW flux (equal to all solar heating below) at each vertical level (in the global time average for an equilibrium climate state) at and above the tropopause (for global averaging, the «vertical levels» can just be closed surfaces around the globe that everywhere lie above or at the tropopause; the flux would then be through those surfaces, which wouldn't be precisely horizontal but generally approximately horizontal).

If there is significant solar heating below the tropopause level then there must be a significant net LW flux up through the tropopause (assuming relatively small convective or kinetic energy transfer through that level), so increasing GHG optical thickness can never saturate the tropopause level forcing at all LW wavelengths (by bringing net LW flux at tropopause to zero) in an equilibrium climate.

If it is correct, then the term Equilibrium Climate Sensitivity would surely be a misnomer, in that no predictable equilibrium is achieved.

(There are equilibrium climates between the points where the runaway starts and where it ends, but they are unstable equilibria, and the equilibrium coverage of snow / ice increases with forcing that would cause warming.)

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.

Heat capacity that is «used» over a longer period of time (penetration of temperature change through the depths of the ocean and up to regions of upwelling) would leave a more persistent residual imbalance, but the effect would only just stall the full change to equilibrium climate, not change the long term equilibrium sensitivity.)

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.