Comment On “AMS2010: Data Gaps And Errors May Have Masked Warming” By Olive Heffernan At The Weblog Climate Feedback

There is a post on the Nature website Climate Feedback by Olive Heffernan titled

AMS2010: Data gaps and errors may have masked warming

This is a remarkable post in that it fails to properly assess all of the data sources for climate system heat changes. Excerpts from the post read

“New analyses provide preliminary evidence that temperature data from the UK Met office may under-estimate recent warming. That’s the conclusion of a talk given here today by Chris Folland of the Met Office Hadley Centre. Folland says that there is a very good chance that there has been more warming over land and over the ocean in the past decade than suggested by conventional data sets, but he says that the issues with land and ocean data are entirely unrelated.’

“For land, the problem of underestimating warming stems from data gaps in the average monthly temperature data set of the Met Office Hadley Centre, known as HadCruT3. Temperatures over the past decade were recently re-analyzed using a european climate model by Adrian Simmons of the European Centre for Medium-Range Weather Forecasts in Reading, UK and colleagues, and are soon to be published in the Journal of Geophysical Research [subscription]. Simmons and colleagues compared air temperature and humidity data collected over the past decade by the Hadley Centre with re-analyzed data for the same period. Average warming over land was larger for the fully sampled re-analyzed data than for the HadCRUT3 temperature data. The difference between the data sets is particularly notable for northeast Canada, Greenland and nothern parts of Asia, areas which are warming particularly rapidly.”

If the land surface temperatures were actually warmer than have been sampled, this results in even more divergence between the surface temperature and lower tropospheric temperature trends which we quantified in

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.

Chris Folland also ignored the unresolved issues and systematic biases that we identified in our 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.

The Heffernan weblog post further writes

“For the ocean data, it’s a different issue. John Kennedy of the Met Office and colleagues previously reported in Nature [subscription] that changes in the methods used to collect sea surface temperature (SST) data at the end of World War II caused problems in comparing pre- and post-war data. Now they have a new analysis (yet to be published) suggesting that smaller changes in data collection methods since the end of the war could also be significant.

Over the past 20 years, the primary source of SST data has changed from ships to ocean buoys. Because ships warm the water during data collection, there has been a drop in recorded SSTs since bouys,which are more accurate, became the main data source. So what could appear to be a relative cooling trend in SSTs over the past decade may actually just due to changes in errors in the data. Scientists are confident that the buoy data are more accurate because they compare favourably with reliable satellite data.”

The upper ocean heat data shows no appreciable warming in the upper ocean since at least 2005 (and perhaps since 2003) as I discussed in my paper

Pielke Sr., R.A., 2008: A broader view of the role of humans in the climate system. Physics Today, 61, Vol. 11, 54-55.

The satellite monitored surface temperatures similarly show a lack of warming over this time period; the current global sea surface temperature trends can be viewed at the GISS website (see) where for the period 2003 to 2009 on the annual average, there is a even negative trend in this time period for some latitude bands (see) [see also the land and ocean temperature changes figure in the section “Annual Mean Temperature Change for Land and Ocean in where a divergence between the land and ocean data trens in the last 10 years is quite distinct].

While, whether the trends are positive or negative from 2003 to 2009 does not refute a longer time global warming (which could, of course, recommence), statements by Chris Folland and John Kennedy that can be easily shown to conflict with even a cursory examination of the data, will result in a dismissal of their conclusions by objective climate scientists.

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