Friday, August 3, 2012

New paper finds climate stabilized from 2000-2010 due to net negative feedbacks

A paper published this week in the Journal of Climate finds from observations that the global climate stabilized from 2000-2010 due to net negative feedbacks. The IPCC erroneously assumes net feedbacks are positive resulting in a 'runaway greenhouse effect'. The net negative feedback of -1.15 W/m2/K found by this paper is almost the same as the positive forcing alleged to occur from a doubling of CO2 levels [1.3 W/m2/K], which would take over 200 years to occur at the present rate.

Observations of climate feedbacks over 2000-2010 and comparisons to climate models

A. E. Dessler
Dept. of Atmospheric Sciences, Texas A&M University, College Station, TX 979-862-1427
Feedbacks in response to climate variations during the period 2000-2010 have been calculated using reanalysis meteorological fields and top-of-atmosphere flux measurements. Over this period, the climate was stabilized by a strongly negative temperature feedback (~ −3 W/m2/K); climate variations were also amplified by a strong positive water vapor feedback (~ +1.2 W/m2/K) and smaller positive albedo and cloud feedbacks (~ +0.3 and +0.5 W/m2/K, respectively). These observations are compared to two climate model ensembles, one dominated by internal variability (the control ensemble) and the other dominated by long-term global warming (the A1B ensemble). The control ensemble produces global average feedbacks that agree within uncertainties with the observations, as well as producing similar spatial patterns. The most significant discrepancy was in the spatial pattern for the total (shortwave + longwave) cloud feedback. Feedbacks calculated from the A1B ensemble show a stronger negative temperature feedback (due to a stronger lapse-rate feedback), but that is cancelled by a stronger positive water vapor feedback. The feedbacks in the A1B ensemble tend to be more smoothly distributed in space, which is consistent with the differences between ENSO climate variations and long-term global warming. The sum of all of the feedbacks, sometimes referred to as the thermal damping rate, is −1.15±0.88 W/m2/K in the observations, −0.60±0.37 W/m2/K in the control ensemble. Within the control ensemble, models that more accurately simulate ENSO tend to produce thermal damping rates closer to the observations. The A1B ensemble average thermal damping rate is −1.26±0.45 W/m2/K.


  1. Excuse me, but is this the same Andrew Dessler that has been telling us positive feedbacks dominate and that the globe is "virtually guaranteed" to warm by several degrees this century due to positive feedbacks from water vapor?

    Did he not also state that could only be avoided if some yet unknown negative feedback were discovered?

    I don't trust one thing this guy says anymore.

  2. Dessler compares observations with two kinds of differently fudged-up models and declares one of them better - fun thing is, that's just wiggle matching - both models are junk without predictive skill. (As we would have heard from any successful prediction, you can bet on that)

  3. site claiming lapse rate feedback at present is neutral, ~equally balanced between + and -