Open Thread

Consider the published heating rate/cooling rate error for the RRTM and RRTM-G radiative transfer components which are used in the time-step-iterated earth system models. This error value is computed using LBLRTM as the reference. 
 
“…the computed cooling rates agree to within 0.1 K/day in the troposphere and 0.3 K/day in the stratosphere…”
https://rtweb.aer.com/rrtm_description.html

“…the computed cooling rates generally agree to within 0.1 K/day in the troposphere and 0.3 K/day in the stratosphere…”
https://rtweb.aer.com/rrtmg_lw_description.html

To compare, let’s use the UAH linear trend for the lower troposphere temperature anomaly. This gives a slight warming at 0.16 deg C(K) per decade for the entire record. This is 0.000044 deg C(K) per day.

The published ~+/- 0.1 deg C(K) per day uncertainty interval is ~4500 times greater than the long-term trend being investigated for potential longwave influence from emissions of CO2, CH4, N2O. 
 
Also, using days as a time step to be consistent with the published heating/cooling rate error, the uncertainty builds to ~+/- 2 deg C(K) after just 365 steps, assuming the RSS method is used for propagation. There is no value at all for detection or attribution of the factor being investigated, concerning CO2 and the other IR-active trace gases.

The conclusion must be that there was never any sound justification for using time-step-iterated climate models to generate scenarios of any hypothetical emissions pathway.  So let’s please stop giving unearned credit to any of the more moderate emission scenarios.  None are reliable representations of what to expect.

And let’s take this requirement seriously, as stated in the 5-23-2025 EO “Restoring Gold Standard Science” in Sec 4(c): “When using scientific information in agency decision-making, employees shall transparently acknowledge and document uncertainties, including how uncertainty propagates throughout any models used in the analysis.”

This is critically important within the DOE, as Secretary Wright has recently named Dr. Matthew Wielicki as director of the effort to write the next version of the National Climate Assessment.

That is all for now. Thank you for your patience in this matter.