Comments On The Poor Post “Lessons from Past Predictions: Hansen 1981” By Dana1981 At The Skeptical Science

There is a post on Skeptical Science by dana1981 [another person who will not list their real name but does have a description of themselves here] titled

Lessons from Past Predictions: Hansen 1981

who concludes that the Hansen 1981 predictions are corresponding quite well with observations. He presents the figure below

Hansen 1981 projections vs observations

Using, the “eyecrometer” view, it is clear that the models and observations are in very good agreement.

However, dana1981 fails to take the next step and to compare with the other predictions made by Jim Hansen’s model (GISS) to see if they are in disagreement with the real world. The first disagreement is presented in the post

Comment On Ocean Heat Content “World Ocean Heat Content And Thermosteric Sea Level Change (0-2000), 1955-2010″ By Levitus Et Al 2012

where [highlight added]

Thus either using the 1955 to 2010 time period, or the shorter time period from 1990 to 2010 in the Levitus et al 2012 paper, the diagnosed magnitudes of ocean warming and global warming are significantly less than claimed by Jim Hansen in 2005. This discrepancy is even large if we use the NOAA’s Pacific Marine Environmental Laboratory data.

Dana1981 should comment on this discrepancy between real world observations and the Hansen et al model predictions.  This omission on his part, which I presume he will claim  is because he is focusing just on the surface temperature trends, is inappropriate, as Jim Hansen’s predicted surface temperature trends are a result of his model’s radiative imbalance.  Moreover, Levitus et al 2012 reported that

One third of the observed warming occurs in the 700-2000 m layer of the ocean

This warming would not be available to increase the surface temperatures. If the surface temperature trends agree between the GISS model but the radiative imbalance does not and some of the heat is sequestered deep into the ocean,  than  dana1981 cannot correctly conclude that the surface temperature trend values are robust. He would now have to claim that the Levitus et al analysis is in error.

Dana1981, in his post, also has a section titled “Christy’s Poor Critique” based on the post on my weblog titled

John Christy’s Comment On “If You Want To Roll The Climate Dice, You Should Know The Odds”

Dana1981 writes

Of course Hansen et al. did not model atmospheric temperature changes, they modeled surface temperature changes, so this is not an apples-to-apples comparison.

Actually, Hansen et al must have modeled atmospheric temperature changes! They may not have presented  them in their 1981 paper, but they certainly are in the model. Indeed, the observations show a growing divergence in time between the surface and lower tropospheric temperatures, as we report in the papers

Klotzbach, P.J., R.A. Pielke Sr., R.A. Pielke Jr.,  J.R. Christy, and R.T. McNider, 2009: An alternative explanation for differential temperature trends at the  surface and in the lower troposphere. J. Geophys. Res., 114, D21102, doi:10.1029/2009JD011841.

Klotzbach, P.J., R.A. Pielke Sr., R.A. Pielke Jr.,  J.R. Christy, and R.T. McNider, 2010: Correction to: “An alternative explanation for differential temperature trends at the  surface and in the lower troposphere. J. Geophys. Res., 114, D21102, doi:10.1029/2009JD011841″, J. Geophys. Res.,  115, D1, doi:10.1029/2009JD013655.

The “eyecometer” view of the lower tropospheric analysis, reproduced below from RSS MSU, shows a flat trend since about 2001,

which clearly conflicts with the Hansen et al al surface trend in recent years. I present the RSS data (rather than the also excellent Christy and colleagues data) since dana1981 has not claimed this analysis is bad.

This time period might still be too short to satisfy Grant Foster or dana1981, but, if they are going to claim that the Hansen et al prediction is accurate, they also need to statistically compare the behavior of the lower tropospheric temperatures and ocean heat content between the model and observations.

Indeed, we did compare surface and lower tropospheric trends in the Klotzbach et al 2010 paper where we obtained the data from Gavin Schmidt’s site at, where we found amplification factors of 1.1 over land and 1.6 over ocean. Thus, the surface and lower tropospheric temperature trend data are closely linked.

Thus this data is available for dana1981 to compare between the models and the observations.

Dana1981 continues his poor analysis when he writes

“Christy believes the discrepancy is due to a bias in the surface temperature record, but on the contrary, the surface temperature record’s accuracy has been confirmed time and time again (i.e. Peterson et al. 2003, Menne et al. 2010, Fall et al. 2011 [which includes Anthony Watts as a co-author!], Muller et al. 2011 [the BEST project], etc.).  There are good reasons to believe the discrepancy is primarily due to problems in the atmospheric temperature record…”

Actually, Fall et al 2011 showed that there are significant problems with the surface temperature data with respect to siting. As we report in Fall et al 2011

Temperature trend estimates vary according to site classification, with poor siting leading to an overestimate of minimum temperature trends and an underestimate of maximum temperature trends, resulting in particular in a substantial difference in estimates of the diurnal temperature range trends. The opposite‐signed differences of maximum and minimum temperature trends are similar in magnitude, so that the overall mean temperature trends are nearly identical across site classifications.

Dana1981 also ignores the other issues with the surface temperature data that we reported on in the paper

Pielke Sr., R.A., C. Davey, D. Niyogi, S. Fall, J. Steinweg-Woods, K. Hubbard, X. Lin, M. Cai, Y.-K. Lim, H. Li, J. Nielsen-Gammon, K. Gallo, R. Hale, R. Mahmood, S. Foster, R.T. McNider, and P. Blanken, 2007: Unresolved issues with the assessment of multi-decadal global land surface temperature trends. J. Geophys. Res., 112, D24S08, doi:10.1029/2006JD008229.

Dana1981 correctly refuted my analysis of the sea ice trend. But now he has followed up with a poor, incomplete analysis. Lets see if he will now admit that he also needs to eat some crow. :-)  Dana1981’s post Lessons from Past Predictions: Hansen 1981, rather than John Christy’s, is a “Poor Critique”.

Comments Off on Comments On The Poor Post “Lessons from Past Predictions: Hansen 1981” By Dana1981 At The Skeptical Science

Filed under Climate Science Misconceptions, Climate Science Reporting, Uncategorized

Comments are closed.