Dr. Judith Curry speaks out on climate science’s fatal flaw – the failure to explore and understand uncertainty

Guest essay by Larry Hamlin

Dr. Judith Curry conducted an interview on British radio on February 6th  addressing, among many topics, how the politicalization of climate science created and driven by the UN IPCC process has robbed scientists of the opportunity to explore the legitimate, extremely important and yet unaddressed issues of how natural climate change drivers impact the earth’s climate. Her excellent broadcast can be found here:

During the course of her interview Dr. Curry addressed the underlying assumptions contained in the UN IPCC process at its very beginning which simply assumed without establishing scientific evidence that anthropogenic activity was driving “global warming” (which was  subsequently modified to “climate change” after the global temperature “pause”).

This theme was effectively captured by her characterization during the broadcast when she noted the failures of climate models to address pre 1950 natural climate variation –  “If science can’t explain climate shifts pre 1950, how can we trust today’s climate models?”

She noted that the IPCC never bothered to do the “hard work” to determine how natural climate variation affected climate change but instead relied on “expert judgement” that man made actions were controlling thus neglecting any opportunity to advance climate science in this very important area.

Dr. Curry has addressed this topic in previous articles written by her (https://judithcurry.com/2014/08/24/the-50-50-argument/) where she challenged the highly questionable computer modeling techniques which attempt to manufacture a divergence between unforced and anthropogenic forced climate model ensemble runs.

In these prior articles she concluded that in using this model driven detection and attribution technique “the IPCC has failed to convincingly demonstrate ‘detection.’

“Because historical records aren’t long enough and paleo reconstructions are not reliable, the climate models ‘detect’ AGW by comparing natural forcing simulations with anthropogenically forced simulations.”

She noted “The IPCC then regards the divergence between unforced and anthropogenically forced simulations after ~1980 as the heart of the their detection and attribution argument. See Figure 10.1 from AR5 WGI (a) is with natural and anthropogenic forcing; (b) is without anthropogenic forcing:”

Dr. Curry pointed out a number of critical flaws in these comparisons as follows:

“Note in particular that the models fail to simulate the observed warming between 1910 and 1940.

The glaring flaw in their logic is this. If you are trying to attribute warming over a short period, e.g. since 1980, detection requires that you explicitly consider the phasing of multidecadal natural internal variability during that period (e.g. AMO, PDO), not just the spectra over a long time period.

Attribution arguments of late 20th century warming have failed to pass the detection threshold which requires accounting for the phasing of the AMO and PDO.

It is typically argued that these oscillations go up and down, in net they are a wash. Maybe, but they are NOT a wash when you are considering a period of the order, or shorter than, the multidecadal time scales associated with these oscillations.

Further, in the presence of multidecadal oscillations with a nominal 60-80 yr time scale, convincing attribution requires that you can attribute the variability for more than one 60-80 yr period, preferably back to the mid 19th century.

Not being able to address the attribution of change in the early 20th century to my mind precludes any highly confident attribution of change in the late 20th century.”

In these prior articles Dr. Curry concludes that UN IPCC climate models are unfit for use for this purpose, use circular reasoning in claiming detection and fail to assess the impact of forcing uncertainties regarding attribution assertions.

During the broadcast Dr. Curry noted that climate models like those utilized by UN IPCC which attempt to connect climate impacts as being driven by human action in many respects represent “self fulfilling” prophecies from a politically driven agency that has “lost objectivity”  because of its bias in disregarding natural climate variability because its charter is solely focused on anthropogenic climate change.

Dr. Curry also addressed during the broadcast the recent data debacle of NOAA where this organization which is supposed to be preeminent in measuring and evaluating global temperature data has been extremely careless and incompetent in handling it’s temperature data.

She addressed the context of NOAA’s data debacle as being driven by political pressure from the Obama administration which desired this result to support its activities at the Paris climate conference.

She indicated that she has been in contact with NOAA scientist Dr. John Bates over the last 18 months discussing his experience with the lack of scientific rigor in NOAA’s handling of data sets where critical temperature data has not been properly archived, documented or evaluated consistent with standards established by NOAA itself. She noted that Dr. Bates has an extensive discussion of these NOAA data problems on her blog Climate Etc.

She further noted that given the importance that NOAA temperature data plays in global and national regulatory policy decision making regarding climate issues that can require the commitment of trillions of dollars that such data sets must receive and comply with the most rigorous data handling standards which clearly have not been followed.

She believes that funding for the study of natural climate variation needs to be significantly increased and that government political pressure has driven almost all funding toward anthropogenic focused studies.

She also said that in her judgement the climate impacts of man made CO2 emissions on global climate are measured on a “tiny scale”.

She encouraged people who have concerns about the validity of arguments alleging man made climate change to continue to speak out about their concerns.