Sentences with phrase «equilibrium climate sensitivity so»

We have no direct observations of equilibrium climate sensitivity so we have to rely on some form of theory or indirect observations from paleo, at least in part.

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?

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-.

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.

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.

Global temperature change is about half that in Antarctica, so this equilibrium global climate sensitivity is 1.5 C (Wm ^ -2) ^ -1, double the fast - feedback (Charney) sensitivity.

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»).

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.

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.

Depending on meridional heat transport, when freezing temperatures reach deep enough towards low - latitudes, the ice - albedo feedback can become so effective that climate sensitivity becomes infinite and even negative (implying unstable equilibrium for any «ice - line» (latitude marking the edge of ice) between the equator and some other latitude).

But so does the equilibrium climate sensitivity, only after the forcing ceases, e.g., we quite raising CO2 concentrations with our emissions.

Over very long time periods such that the carbon cycle is in equilibrium with the climate, one gets a sensitivity to global temperature of about 20 ppm CO2 / deg C, or 75 ppb CH4 / deg C. On shorter timescales, the sensitivity for CO2 must be less (since there is no time for the deep ocean to come into balance), and variations over the last 1000 years or so (which are less than 10 ppm), indicate that even if Moberg is correct, the maximum sensitivity is around 15 ppm CO2 / deg C. CH4 reacts faster, but even for short term excursions (such as the 8.2 kyr event) has a similar sensitivity.

So, turning to the relationship between Transient Climate Response (TCR) and Equilibrium Climate Sensitivity (ECS).

It is possible that effective climate sensitivity increases over time (ignoring, as for equilibrium sensitivity, ice sheet and other slow feedbacks), but there is currently no model - independent reason to think that it does so.

The figure of 1.7 C is actually for TCR (transient climate response)-- so it is still possible that ECS (equilibrium climate sensitivity) is as high as 2.5 C.

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.

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.

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).

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.

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.

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.

The methods of Black Box Model Identification applied to an energy balance model provide directly the so called «equilibrium sensitivities» with respect to three inputs: CO2; solar and volcanic activities; this is shown by Prof. de Larminat in his book «Climate Change: Identifications and projections «[77] where Identification techniques well known in industrial processes, are applied to 16 combinations of historical reconstructions of temperatures (Moberg, Loehle, Ljungqvist, Jones & Mann) and of solar activity proxies (Usoskin - Lean, Usoskin - timv, Be10 - Lean, Be10 - timv) for the last millennium, with some series going back to year 843.

No: that is the beauty of using top of atmosphere radiative balance data — it automatically reflects the flow of heat into the ocean, so thermal inertia of the oceans is irrelevant to the estimate of equilibrium climate sensitivity that it provides, unlike with virtally all other instrumental methods.

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.

A lower ratio would yield a higher climate sensitivity estimate — for a ratio of 0.6, the range would be 2.2 — 3.8 C. TCR involves an interval of about 70 years, and so it is unlikely that a response to doubled CO2 would exceed 70 percent of the equilibrium value in an interval that short.

In doing so, he arrived at an equilibrium climate sensitivity estimate of 1.99 °C with a 95 % confidence range of it being between 1.75 °C and 2.23 °C.

Re 416 Bernd Herd — in climate science, for global climate change, specifically a global (average surface) temperature change in response to a global (typically average net tropopause - level after stratospheric adjustment) radiative forcing (or other heat source — although on Earth those tend not to be so big), where the radiative forcing may be in units of W / m ^ 2, so that equilibrium climate sensitivity is in K * m ^ 2 / W (it is often expressed as K / doubling CO2 as doubling CO2 has a certain amount of radiative forcing for given conditions).

«Using a probabilistic setup of a reduced complexity model and an ensemble of an Earth System Model, we showed that unforced climate variability is important in the estimation of the climate sensitivity, in particular when estimating the most likely value, and more so for the equilibrium than for the transient response.

They do so in many coupled GCMs; in GISS - E2 - R the effective climate sensitivity relevant to Historical forcing is ~ 85 % of the equilibrium value.

The current energy imbalance (just a little less than 1 W / m2) implies that the planet would need to warm by ~ 1 x S / 3.7 ºC to restore an equilibrium, and using the standard climate sensitivity of 3ºC for a doubling of CO2, implies a committed warming of 0.8 ºC or so.