Guest Post by Bob Tisdale
Pierre Gosselin of NoTrickZone reports on a paper that confirms the slowdown in global surface warming has not been occurring at the poles. See Pierre’s post German Experts: New Paper By Gleisner Shows 2013 Cowtan And Way Arctic Data Hole Paper Was A Lemon.
You’ll recall that Cowtan and Way (2013) Coverage bias in the HadCRUT4 temperature series and its impact on recent temperature trends were able to squeeze a few more drops of global warming trend from the data during the hiatus period by taking HADCRUT4 data and using a statistical method to infill the missing data at the poles, especially in the Arctic where polar amplification is more prevalent.
But a new paper, Geisner et al. (2015) Recent global warming hiatus dominated by low-latitude temperature trends in surface and troposphere data, undermines those Cowtan and Way efforts. The abstract reads (my boldface):
Over the last 15 years, global mean surface temperatures exhibit only weak trends. Recent studies have attempted to attribute this so called temperature hiatus to several causes, amongst them incomplete sampling of the rapidly warming Arctic region. We here examine zonal mean temperature trends in satellite-based tropospheric data sets (based on data from (Advanced) Microwave Sounding Unit and Global Navigation Satellite System Radio Occultation instruments) and in global surface temperatures (HadCRUT4). Omission of successively larger polar regions from the global mean temperature calculations, in both tropospheric and surface data sets, shows that data gaps at high latitudes cannot explain the observed differences between the hiatus and the prehiatus period. Instead, the dominating causes of the global temperature hiatus are found at low latitudes. The combined use of several independent data sets, representing completely different measurement techniques and sampling characteristics, strengthens the conclusions.
There’s nothing surprising about that. We reported the same thing a year ago in the post Cowtan and Way (2013) Adjustments Exaggerate Climate Model Failings at the Poles and Do Little to Explain the Hiatus. The following graph is Figure 2 from that post.
The WattsUpWithThat cross post is here, for those who want to run through the comments.
I ended that post with:
Those who promote the Cowtan and Way (2013) revisions to the HADCRUT4 data don’t understand where the hiatus is taking place and they don’t understand the model failings at simulating polar amplification—or—they are intentionally being misleading.