After the fiasco with his 'iostatic' paper, Anthony Watts, science illiterate extraordinaire, must be feeling a tad sensitive. That may be why he thought to post an article supposedly about climate sensitivity. Click here for an archived copy.
I say 'supposedly' because the author seems to be putting all the different types of sensitivity into one basket. I'm no expert so perhaps others will chip in.
There are many ways to represent climate sensitivity. There is Charney sensitivity, equilibrium climate sensitivity (long term), transient climate response (very short term), earth system sensitivity - exceedingly long term. So it can all get confusing and makes it difficult to compare different estimates if you aren't careful to check just what is being discussed. Climate sensitivity types are discussed in realclimate.org here. For example:
We need to start with some definitions. Sensitivity is defined as the global mean surface temperature anomaly response to a doubling of CO2 with other boundary conditions staying the same. However, depending on what the boundary conditions include, you can get very different numbers. The standard definition (sometimes called the Charney sensitivity), assumes the land surface, ice sheets and atmospheric composition (chemistry and aerosols) stay the same. Hansen’s long term sensitivity (which might be better described as the Earth System sensitivity) allows all of these to vary and feed back on the temperature response. Indeed, one can imagine a whole range of different sensitivities that could be clearly defined by successively including additional feedbacks. The reason why the Earth System sensitivity might be more appropriate is because that determines the eventual consequences of any particular CO2 stabilization scenario.There are more recent articles on the topic at realclimate, for example here and here. Dana Nuccitelli wrote a good article on climate sensitivity in the UK Guardian recently, too.
What the WUWT article is claiming, surprise surprise, is that sensitivity is overstated. The author, Barry Brill, has cherry picked a number of papers from among the many that discuss the subject, and makes ridiculous claims, such as:
These new papers devastate the IPCC orthodoxy that current and future global temperatures are mostly driven by greenhouse gas emissions, and will reach dangerous levels later this century. On the other hand, all older papers are blindsided by their apparent failure to take account of the recent data (standstill).Devastate IPCC orthodoxy? Nothing but wishful thinking on the part of a science denier. What about these equally ridiculous claims:
- It is quite conceivable that natural variability (including natural forcing) has historically dwarfed anthropogenic effects and will persistently do so in future.
- ...warming may not resume until mid-century. (I hope someone will tell Barry that warming hasn't stopped!)
- 2013 is ushering in a long-delayed revolution in climate science. A new paradigm is demanded which recognizes that AGW is but one non-determinative component in a ‘non-linear chaotic system’.
- The draft SPM apparently fails to mention that 30-year warming trends have declined each year since peaking in 2003. Or that the latest 10-year period (2003-12) is the coolest decade since satellite records began in 1979.
From the WUWT comments
There are some classic denierisms in the WUWT comments, too. (Archived here.) Here is a sample.
August 31, 2013 at 7:20 pm
Lets not be naive, it is likely reviewers and editors actually held papers until after the March 15 deadline just so they would NOT be included. This is not paranoia, see Judith Curry’s blog for actual suppression of anti-AGW papers that have excellent science
Philip Bradley refers to the more than 830 IPCC authors reporting the work of thousands of scientists as a "small clique" - conspiracy ideation plus - and says:
August 31, 2013 at 8:00 pm
I’d question whether the ‘normal science’ of anthropogenic GHG warming was ever real. IMO it was merely the view of a small clique that captured the IPCC and all the rest of the AGW apparatus, and the large revenue streams that ensued, enabled them to control the narrative and subvert opposing views.
RockyRoad decides name-calling is the answer to science he doesn't like and says:
August 31, 2013 at 9:20 pm
These folks are “Deceitful Anthropogenic Genocidal Warmistas”. More personal and accurate than my previous “Catastrophic Anthropogenic Genocidal Warmista” expansion of the old acronym CAGW.