Via the IPCC's gold-standard temperature dataset, it has become undisputed fact that global warming isn't - experts and pundits alike are searching for the reasons why and how this gross prediction failure took place, with most concurring (even the NY Times) that climate models' sensitivity to a doubling of CO2 levels was severely exaggerated - go figure
(click on chart to enlarge - data sources)
Multiple outlets, including the NY Times, have recently written about new research that is finding climate models' programmed sensitivity to CO2 levels being pegged too high. Sample articles explaining the underlying problem with climate sensitivity research can be found here, here , here, here, and here.
The adjacent chart points to the serious problem with the original high sensitivity estimates from the IPCC and others. (The gold-standard HadCRUT global and CET temperature datasets are plotted.)
In the case of the IPCC, they published a flat-out fear-mongering sensitivity that in computer simulations would produce a temperature increase of +6.4°C (pink line) by 2100AD, if CO2 emissions were not stabilized. This incredibly high computer output was designed to scare policymakers and the mainstream media into action.
And, there are even higher published estimates of sensitivity, which will never happen in the real-world, but are touted as potential realistic threats (climate science gospel) to the gullible with deep pockets and a pennant for government intrusion. Case in point:
“...one of them stated quite openly in a meeting I attended a few years ago that he deliberately lied in these sort of elicitation exercises (i.e. exaggerating the probability of high sensitivity) in order to help motivate political action..." quote from climate modeler, AGW proponent James Annan
As a reminder, this description of a scientist's behavior comports with the incredible level of climate scientist fraud, deception and falsehoods revealed by the embarrassing publication of the Climategate emails. Venal, corrupt anti-science attitudes continue to run blatant and deep in the climate science community.
Back to the chart...in reality, CO2 emissions have not stabilized, they are growing in a 'business as usual' manner yet the impact on global temperatures has been minimal. As the chart depicts, over the last 15 years global warming is increasing at a 0.17°C per century rate, a sliver-fraction of the IPCC absurd sensitivity simulated outcome. Other straight red lines on the chart tell the same story - the IPCC's climate sensitivity produces temperature predictions out-of-touch with this real-world empirical observational evidence.
"But the point stands, that the IPCC’s sensitivity estimate cannot readily be reconciled with forcing estimates and observational data. All the recent literature that approaches the question from this angle comes up with similar answers. By failing to meet this problem head-on, the IPCC authors now find themselves in a bit of a pickle." quote from climate modeler, AGW proponent James Annan
The same story holds true for the chart's plot of Central England Temperatures (CET) (green curve and lines). Over the last 15-years, the CET century trend is a surprisingly minus 3.8°C. That is a significant cooling trend (in contrast, the last 15 years has the U.S. at a minus 0.94°C trend) that should not happen in a high sensitivity, tipping-point type of warming world.
Conclusions:
#1. There is no scientific consensus about the correct climate sensitivity to CO2 levels.
#2. A scientific consensus is building though regarding the IPCC and other climate model agencies having exaggerated the sensitivity in the past, and a need to lower the models' said sensitivity to better match reality.
#3. Past real-world global warming (see jagged red chart curve) is not dangerous, nor accelerating - instead, it is presently flat with an equal possibility of becoming a cooling trend, or resuming its non-alarming warming trend
#4. CO2 levels would appear to have a weak influence on both global and regional temperatures.
#5. The spectacular documented failure of climate agency computer models is likely due to the erroneous (i.e., overly high) sensitivity parameters,
#6. 100% of climate scientists would agree that the current empirical evidence does not support the proclaimed runaway, tipping point acceleration that was supposedly taking place. ;-)
Additional modern temperature and climate-model charts.