C, which is at the high end of the IPCC estimates. Earth system sensitivity by an amount that depends on the time scale considered. By contrast, simpler climate change 2007 the physical science basis pdf-balance models may have climate sensitivity as an explicit parameter.
However the term “equilibrium” is widely used. C, and is very unlikely to be less than 1. Values substantially higher than 4. Other estimates of climate sensitivity are discussed later on. The transient response is lower than the equilibrium sensitivity because the deep ocean, which takes many centuries after a perturbation to reach a new steady state, continues to serve as a sink for heat from the upper ocean. This “may vary with forcing history and climate state”. These extra feedbacks make the ESS larger than the ECS — possibly twice as large — but also mean that it may well not apply to current conditions.
C, which corresponds to a value of λ of 0. In 2001 the IPCC adopted the revised value of 3. C, plus or minus 1. According to Manabe, Charney chose 0.
C as a not-unreasonable margin of error, subtracted it from Manabe’s number, and added it to Hansen’s. Thus was born the 1. The differences in model results are relatively small and may be accounted for by differences in model characteristics and simplifying assumptions. Charney report’s original range of uncertainty: “At that time, this range was on very shaky ground.
Since then, many vastly improved models have been developed by a number of climate research centers around the world. Current state-of-the-art climate models span a range of 2. C, with a “best guess in the light of current knowledge” of 2. This used models with strongly simplified representations of the ocean dynamics. As noted above, the IPCC TAR retained the likely range 1.
For fundamental physical reasons, as well as data limitations, the IPCC states a climate sensitivity higher than 4. The TAR uses the word “likely” in a qualitative sense to describe the likelihood of the 1. Equilibrium climate sensitivity is likely in the range 1. Neglecting other forcings and considering the temperature increase to be an equilibrium increase would lead to a sensitivity of about 1. All numbers are approximate and quite uncertain.
C, while the change in solar forcing is 7. C for climate sensitivity determined by this approach. C “cannot be reconciled with paleoclimatic and geologic evidence, and hence should be assigned near-zero probability. C, with a 54 percent likelihood that it lies outside the IPCC range. The exact range depends on which factors are most important during the instrumental period: “At present, the most likely scenario is one that includes anthropogenic sulfate aerosol forcing but not solar variation.
Although the value of the climate sensitivity in that case is most uncertain, there is a 70 percent chance that it exceeds the maximum IPCC value. This is not good news,” said Schlesinger. C by estimating the change in Earth’s radiation budget and comparing it to the global warming observed over the 20th century. 6 different time scales, ranging from the 11-yr solar cycle to the climate variations over geological time scales.
He found a typical sensitivity of 0. Note Shaviv quotes a radiative forcing equivalent of 3. C best estimate, and 6. C maximum—is, given various uncertainties, consistent with sensitivities of current climate models and with other determinations.