v3.0 has
a higher equilibrium sensitivity (2.7 vs 2.2) and transient sensitivity.
A GCM with relatively low transient response but relatively
high equilibrium sensitivity probably has large thermal inertia, therefore will take longer to equilibrate, and vice versa.
Not exact matches
The current crop of models studied by the IPCC range from an
equilibrium sensitivity of about 1.5 °C at the low end to about 5 °C at the
high end.
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.»
Chris Colose @ 39 — Thanks as always, but I am baffled by your The larger thermal inertia of the ocean is important, but the
higher sensitivity over land than in the ocean is also seen in
equilibrium simulations when the ocean has had time to «catch up,» so that argument doesn't hold as
equilibrium is approached.
Moreover, the timeframe over which the planet comes to
equilibrium increases with
higher climate
sensitivity.
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.
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.
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.
The current crop of models studied by the IPCC range from an
equilibrium sensitivity of about 1.5 °C at the low end to about 5 °C at the
high end.
This
sensitivity is often represented by the
equilibrium climate
sensitivity, but this quantity is poorly constrained with significant probabilities for
high values.
This lag is known as the difference between transient climate
sensitivity (TCS), which is immediate warming, and
equilibrium climate
sensitivity (ECS), which includes the lag time and can be much
higher.
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.
Equilibrium climate
sensitivity is likely in the range 1.5 °C to 4.5 °C (
high confidence), extremely unlikely less than 1 °C (
high confidence), and very unlikely greater than 6 °C (medium confidence)(Note 16).»
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.
Sensitivity in a complex dynamical system is
high at regions of shifts between
equilibrium states but not otherwise and the science of predicting shifts is in it's infancy.
The BEST team also found that the observed warming is consistent with an
equilibrium climate
sensitivity of 3.1 ± 0.3 °C for CO2 doubling, in line with the IPCC climate
sensitivity range, and demonstrates once again that contrary to the persistent claims of Richard Lindzen, the Earth has warmed as much as we expect given a relatively
high climate
sensitivity.
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.
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.
A proposition of this type is a premise to the IPCC's argument for the possibility of a catastrophically
high equilibrium climate
sensitivity (ECS) and this argument must be regarded as unproved in view of the falsity of this premise.
Imposing a flat prior on an observable property, such as the climate feedback or transient climate response, is equivalent to imposing a highly skewed prior on the
equilibrium climate
sensitivity, and therefore results in narrower posterior likelihood ranges on the climate
sensitivity that exclude very
high sensitivities.
Thus, a prior is a possibility for which the probability is
high of a low
equilibrium climate
sensitivity.
On the contrary, the authors stated that to show the robustness of the main conclusion of the paper — a relatively small
equilibrium climate
sensitivity — they deliberately adopted the regression model that gave the
highest climate
sensitivity.
Compared with our prior, theirs emphasizes the
higher values of
equilibrium climate
sensitivity.
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.
The temperature rise at
equilibrium (known, unsurprisingly, as the «
equilibrium» climate
sensitivity) is
higher than the transient climate
sensitivity (how much
higher is uncertain).
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.
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.
Then, you would have the global climate models that offer a
higher equilibrium climate
sensitivity and longer time constants.
[Short response: Mainstream view is that climate
sensitivity (
equilibrium warming for a doubling of CO2) is 1.5 to 4.5 C, though
higher estimates can not be discounted.
Equilibrium climate
sensitivity is likely in the range 1.5 °C to 4.5 °C (
high confidence), extremely unlikely less than 1 °C (
high confidence), and very unlikely greater than 6 °C (medium confidence).