UPDATE Nov 25th: The animation disappeared for some reason. I’ve added it back into the post.
Apparently, one of the proudest achievements of the website SkepticalScience is their “Down the Up Escalator” gif animation. They prominently display it in their right sidebar. The intent of the animation is to show that global temperature anomalies can flatten or cool over decadal or shorter periods while warming over the long term. The first version was created using the Berkley Earth Surface Temperature (BEST) land surface air temperature dataset. That, of course, made SkepticalScience appear two-faced, because the papers associated with the BEST dataset had not yet appeared in any peer-reviewed scientific journals and SkepticalScience downplays any research efforts that haven’t been peer reviewed.
ONE OF THE TRENDS IN THE REVISED ESCALATOR IS MISREPRESENTED
In an effort to distract from their duplicity, SkepticalScience revised and reissued the animation (modified screen cap above), using the average of the GISS LOTI, HADCRUT4, and NCDC land surface air plus sea surface temperature anomaly datasets. If you were to click on the mini “Escalator” animation along the right-hand side of their main page, you’re brought to the updated GISS-, UK Met Office- and NCDC-based Escalator. SkepticalScience describes “The Escalator” animation as (my boldface):
Average of GISS, NCDC, and HadCRUT4 monthly global surface temperature anomalies from January 1970 through August 2012 (green) with linear trends applied to the timeframes Jan ’70 – Oct ’77, May ’77 – Dec ’85, Jan ’86 – June ’94, Nov ’94 – Dec ’00, Jan ’01 – Aug ’12.
You’ll note that they’re now calling it “The Escalator”—no longer calling it the “Down the Up Escalator”. Yet each of the steps in their escalator clearly shows a short-term trend that’s flat or cools slightly.
SkepticalScience misrepresented the trend of the “fourth step”. The time period they selected is November 1994 to December 2000. As it turns out, the only dataset that shows a flat trend during that period is the GISS Land-Ocean Temperature Index (LOTI). Both HADCRUT4 and NCDC have significant warming trends from November 1994 to December 2000 at about 0.08 to 0.09 deg C per decade. The average of the three datasets is approximately 0.06 deg C/decade, and that is a significant warming trend.
Actual Linear Trends During Fourth Step of Escalator
How significant is that 0.06 deg C per decade trend? It’s comparable to the trend in global surface temperatures since 1880.
GISS LOTI Global Surface Temperature Anomalies Since 1880
The following animation will give you an idea what “The Escalator” would look like if SkepticalScience had used the real linear trend for the fourth step. Depending on your browser, you may need to click on the following gif animation.
The Escalator With Actual Linear Trends
A COUPLE OF NOTES
As noted in my WUWT-TV presentation “The Natural Warming of the Global Oceans”, “The Escalator” is an exercise in cherry-picked start and end dates. Proponents of anthropogenic global warming will incorrectly cite “The Escalator” during my blog discussions of ENSO-related upward shifts in Atlantic-Indian-West Pacific (90S-90N, 80W-180) sea surface temperature anomalies. (In recent years, I typically present that dataset as the “Rest-of-the-World”, because I usually now start with the East Pacific data, which shows no warming over the entire 30-year term of the satellite era.) When the disciples of SkepticalScience link “The Escalator”, they are simply trying to distract from the process-caused shifts. Those natural processes were described in the WUWT-TV presentation and detailed with numerous datasets in my book Who Turned on the Heat?
Rest of the World Sea Surface Temperature Anomalies With Linear Trends
The above graph was presented in the post Does The Sea Surface Temperature Record Support The Hypothesis Of Anthropogenic Global Warming?
Proponents of anthropogenic global warming have another, related, inconsequential complaint about my research. They claim the decade-long time periods between the 1986/98/88, 1997/98 and 2009/10 El Niño events are too short for the trends to be significant. Curiously, when SkepticalScience is trying to make a point, they have no trouble presenting a series of decadal trends, and when SkepticalScience is trying to mislead their followers, they have no trouble misrepresenting the trend for a shorter 6-year period. Apparently, linear trends over periods as short as 6 years do have significance. Looks like another example of the double standards of the proponents of anthropogenic global warming.
In the next few days, I’ll present PBS’s sleight of hand about “The Escalator” when they presented it in their Frontline report Climate of Doubt. They were pretty blatant about it.