| on Apr 8, 2008, 03:06 PM E.S.T.
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As Climate Science offers, we are open to the presentation of
announcement of papers and of viewpoints by individuals
actively involved in the climate science and climate policy community
who want to widely distribute their views and analyses on climate
science. Today, Climate Science presents a guest weblog by Christopher
Monckton on the issue of radiative feedback. Christopher Monckton has
been an outspoken commentator on climate policy issues, however, his
guest weblog on Climate Science concerns a science issue; namely what
is the magnitude of the radiative feedback as reported by the IPCC?
Climate Science has weblogged on this subject in
Climate
Metric Reality Check #1 - The Sum Of Climate Forcings and Feedbacks Is
Less Than The 2007 IPCC Best Estimate Of Human Climate Forcing Of
Global Warming
Other climate scientists are encouraged to submit guest weblogs
which support or seek to refute the analysis presented below.
Ultimately, each contribution of this type needs to be submitted to
peer reviewed scientific journals which is the most appropriate
aribitrator of science.
Guest Weblog Christopher Monckton
In the IPCC’s methodology, climate sensitivity ΔTλ to radiative forcing is the product of three factors:
1. Tropopausal radiative forcing ΔF
ΔF ≈ 5.35 ln(C/C0) ==> ΔF2x ≈ 5.35 ln 2 W m-2, (1)
where (C/C0) is a proportionate increase in CO2 concentration and, specifically, ΔF2x ≈ 3.708 W m-2 is the radiative forcing at CO2
doubling. For simplicity, no significant error will arise here if it is
assumed that all other anthropogenic forcings are slightly
net-negative, so that ΔF2x ≈ 5 ln 2 ≈ 3.466 W m-2.
2. The no-feedbacks climate sensitivity parameter κ
κ = ΔTκ / ΔF = ΔTλ / (ΔF + bΔTλ) °K W-1 m2, (2)
where ΔTκ is the temperature response to forcings only, without feedbacks; ΔTλ is the temperature change in response to forcings plus feedbacks; and b is the sum in W m-2 °K-1 of all unamplified temperature feedbacks. The key parameter κ is not mentioned in IPCC (2007), and no error-bars are given. The value κ ≈ 0.313 °K W-1 m2 implicit in IPCC (2007) is the reciprocal of the “radiative cooling response” -
“Under these simplifying assumptions the amplification [f] of the global warming from a feedback parameter [b] (in W m-2 °C-1) with no other feedbacks operating is 1 / (1 + [bκ -1]), where [κ -1] is the ‘uniform temperature’ radiative cooling response (of value approximately -3.2 W m-2 °C-1; Bony et al., 2006). If n independent feedbacks operate, [b] is replaced by (λ1 + λ 2+ … λ n).” (IPCC, 2007: ch.8, footnote) Read rest...
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