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Suricat, here's hot from the press an excellent presentation by Richard Lindzen which indicates extremely strong empirical evidence that climate sensitivity is very low approx 0.5 deg C.
Er, I concur with a caveat.
To me the sensitivity of a system is its ability to respond to inputs, but we also need to know whether the system's response is negative, or positive, to the input applied. Knowing that Dr Lindzen excels in the hydrosphere field, I assume that his findings are related to this (the hydrosphere). In which case, I'd say that climate sensitivity is very highly negative to increasing temps on a macro scale, but very highly positive to increasing temps on a radiative scale. Thus, it's a very sensitive thermostat that is set to warm radiatively, but is outweighed by its macro latent transport and cloud generating (insolation reflecting) properties.
However, the negative response is negated where water from the surface is unavailable (either by evaporation, or transpiration) from a region downwind (from "prevailing" winds) as precipitation.
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The only conclusion that I can draw from it is that there is a strong negative feedback mechanism that responds to anthropic warming.
Yes. Latent transport and cloud reflection of insolation. However, the anthropogenic summation is inconsequential to my belief.
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Whether it's Lindzen's iris effect or increased organic material in the atmosphere increasing cloud cover doesn't matter as the effect of the phenomenon has been clearly measured. I think the piece of work by Lindzen will go down in the annals as a real tipping point in the AGW debate.
Well I'd rate this as a parallel to the Miskolczi revelation. Hovever, the "Iris Effect" only explains the 'rationale' behind certain types of cloud that radiate into outer space, and "increased organic material" in the atmosphere doesn't affect the 'relative humidity' (RH) factor at near surface altitudes where climate materialises.
OK, so Dr Lindzen supports latent transport, but I'm unsure of his support to 'cloud condensation nuclei' (CCN) based on the available CCN naturally occurring within the atmosphere. No mater the level of solar wind, the CCN are already there.
A more rational explanation for cloud cover can be found in the Clausius-Clapeyron relationship for pressure and temperature. No mater the level of CCN forcing a possible pricipitation, temperature and pressure of surface water and atmosphere dictates the rate of evaporation. Thus, abundant CCN can only force precipitation and a reduction in altitude of the tropopause, but if the troposphere is "de-watered" of water vapour (WV) to sufficient degree the "radiative" element of feedback is also reduced (reducing the positive temp feedback of the "thermostat").
IOW, I consider that WV is responsible for most of the "greenhouse effect" (GHE) that we enjoy, but it's also responsible for the negative side of GHE when WV over-saturates the troposphere.
It's a job to determine which side of the "thermostat" is most persistent!
Perhaps we are coming to a new Ice Age? This is the most likely outcome from historical record.
Best regards, suricat.