Also in some datasets the ocean warming in the top 700 meters is rather small, with
very small uncertainties (Levitus GRL 2012), pushing the sensitivity down further.
Not exact matches
Already the
uncertainties in measurements using the best of these clocks are
smaller than those in measurements using the
very best cesium standards.
Despite the various
uncertainties in what we know about P1 and P2 so far, and regardless of their surface reflectivities, these bodies are clearly
very small compared to both Pluto (2284 km diameter) and Charon (1192 km diameter).
When faced with durable
uncertainty on many fronts — in the modeling of the atmosphere, in data delineating past climate changes, and more — pushing ever harder to boost clarity may be scientifically important but is not likely to be
very relevant outside a
small circle of theorists.
The IPCC range, on the other hand, encompasses the overall
uncertainty across a
very large number of studies, using different methods all with their own potential biases and problems (e.g., resulting from biases in proxy data used as constraints on past temperature changes, etc.) There is a number of single studies on climate sensitivity that have statistical
uncertainties as
small as Cox et al., yet different best estimates — some higher than the classic 3 °C, some lower.
However, posterior CDF points using a uniform prior don't provide
very good matching, particularly for
small values of the CDF (corresponding to the lower bound of two - sided
uncertainty ranges).
How do you reconcile
very large
uncertainty re climate science in general with apparently
very limited
uncertainty re ECS and impacts (you seem
very sure both are
small)?
Almost all the
uncertainty in fact arose from the statistical fitting of the regression line, with only a
small contribution from
uncertainties in radiative forcing measurements, and
very little from errors in the temperature data.
BUT as Willis has pointed out these are
very very small actual changes in temperature with unknown
uncertainties (but no doubt larger than they admit).
A
small uncertainty in the initial conditions leads to a
very large range of possible solutions.
So April and May 2010 are based on a
very small subset of temperature readings and huge parts of the earth are not covered for those month, hence the huge
uncertainty.
My nominal ECS range is
very close to yours, though slightly
smaller and with similar
uncertainty bounds.
Yes, I deliberately glossed over the state / path - dependence issue and «real» stochasticity, this can indeed lead to a
small uncertainty in the equilibrium achieved in a given experiment, but this
uncertainty is
very small indeed in model world, and I am sure that most scientists think it to be
small in the real world too - so long as we are only talking about moderate differences in climate state, compatible with the present day climate.