SkepticalScience recently produced a YouTube video which claimed to show that the rate of global warming has not slowed in recent years. See their post here, which states:
This replicates the result of a study by Foster and Rahmstorf (2011) under slightly different assumptions.
I later produced a video that explained one of the flaws in their approach. Basically, I’ve illustrated and discussed why they cannot use linear regression analyses to remove the effects of El Niño and La Niña events.
Now blogger Clyde informs WattsUpWithThat that SkepticalScience is saying they will be removing their video because it does “…not represent a consensus in the peer-reviewed results…” See the SkepticalScience post Has the rate of surface warming changed? 16 years revisited. (Thanks, Clyde.)
In the recent SkepticalScience post they note:
The video was based on an approach pioneered by Lean and Rind (2008) and Foster and Rahmstorf (2011), by determining the contribution of known influences on global temperature to best explain those temperatures. However this approach can give misleading results if significant influences on temperature are missing from the analysis, or if wrong influences are included.
They’ve also overlooked the other factor that I’ve been arguing for years: that El Niño and La Niña events are integral parts of the surface temperature record and that ENSO indices do not represent the impacts of El Niño and La Niña events on global temperatures—that there are ENSO residuals. This was briefly mentioned in the closing remarks of Trenberth et al (2002):
Although it is possible to use regression to eliminate the linear portion of the global mean temperature signal associated with ENSO, the processes that contribute regionally to the global mean differ considerably, and the linear approach likely leaves an ENSO residual.
Those ENSO residuals are blatantly obvious in the sea surface temperature anomalies of the Atlantic, Indian and West Pacific Oceans, and they present themselves as upward shifts in the sea surface temperature anomalies there. I’ve been presenting those shifts for years using satellite-era sea surface temperature data. Refer to the above video and my illustrated essay “The Manmade Global Warming Challenge” [42MB].
SkepticalScience has also conveniently overlooked Compo and Sardeshmukh (2010) “Removing ENSO-Related Variations from the Climate Record”
, which. I’ve noted in the past that Compo and Sardeshmukh (2010) is a step in the right direction. Compo and Sardeshmukh (2010) state (my boldface):
An important question in assessing twentieth-century climate is to what extent have ENSO-related variations contributed to the observed trends. Isolating such contributions is challenging for several reasons, including ambiguities arising from how ENSO is defined. In particular, defining ENSO in terms of a single index and ENSO-related variations in terms of regressions on that index, as done in many previous studies, can lead to wrong conclusions. This paper argues that ENSO is best viewed not as a number but as an evolving dynamical process for this purpose.
That aside, SkepticalScience goes on to discuss the factors that they believe are important, but that they have not considered in their video, and just as importantly, that are not considered by Foster and Rahmstorf or similar papers.
SkepticalScience begins their conclusion (my boldface):
Where does this leave us? In order to reliably interpret surface temperature variations we need a good idea of all the causal factors, including El Niño, solar irradiance, volcanic eruptions, observational biases, changes in ocean circulation and possible long term oscillations. Fitting the surface temperature record is attractive because surface temperatures are easy to understand, and the calculations are easily reproducible by non-specialists. However it may be that the surface temperature record is simply too complex to analyse in this way.
I will agree with the author of the SkepticalScience post. The surface temperature record is too complex to analyze in that way. The sea surface temperature and ocean heat content data must be broken down into subsets to show the natural causes of the warming.
The more direct measure of global warming provided by measuring the energy content of the climate system avoids many of these problems, although the observational record is shorter and less complete (e.g. Church et al 2011).
SkepticalScience fails to consider that there are natural explanations for the increase in Ocean Heat Content as well. Refer again to my essay “The Manmade Global Warming Challenge”.
The final paragraph of the SkepticalScience post reads:
There will undoubtably be new developments in the measurement and attribution of short term trends over the coming months, and we will report new results as they are released. The ’16 years’ video still contains useful material for showing how natural influences impact global temperatures and so we aim to produce a new version in future. However the conclusions of the current video do not represent a consensus in the peer-reviewed results, and thus we will be withdrawing the current version.
I, on the other hand, will not be withdrawing my video.
SkepticalScience have clearly stated why they believe papers like by Lean and Rind (2008) and Foster and Rahmstorf (2011) are flawed. Will SkepticalScience be correcting all of their past posts that reference those papers, and the numerous other papers with similar results, in an effort to reflect their change in opinion? If they don’t, their readers will be even more confused.
This recent SkepticalScience post also appears to have established a precedent. Does their misleading escalator “represent a consensus in the peer-reviewed results”? Nope. Will SkepticalScience be withdrawing it?
It appears that SkepticalScience is just a confused as the climate science community about the recent slowdown in the rate of warming. But it’s very obvious what caused it. There hasn’t been a El Niño event since the one in 1997/98 that was strong enough to release a sufficient amount of naturally created warm water from below the surface of the tropical Pacific to raise global surface temperatures more than a few hundredths of a degree.
There’s one thing for sure: When an alarmist now attempts to use Foster and Rahmstorf (2011) or any similar paper in an upcoming discussion about global warming, a skeptic can now link to the recent SkepticalScience post that argues against the methods used. And to make it easy for you, here’s the address: