In the following paper, we empirically calculated the climate sensitivity using temperatures from the latest deep-ocean measurements, several sea-surface datasets and land (in-ground) observations.  We developed a 1-D model that was trained on the various combinations of the data available, essentially accounting for the change in the number of joules in the land and ocean layers through time.  Using the period from 1970 to 2021 we ran several thousand simulations by varying the input datasets and adjustable parameters, principally the ocean diffusion coefficients between the layers.  Forcing was provided by SSP245.  The central-value solution for the ocean and land climate system was +1.86 °C (1.48 to 2.15) for the effective climate sensitivity to doubled CO2.  This value is cooler than the “most-likely” range estimated by the IPCC AR6 of 2.5-4.0 °C.

Spencer, R.W. and J.R. Christy, 2023: Effective climate sensitivity distributions from a 1D model of global ocean and land temperatures trends, 1970-2021.  Theoretical and Applied Climatology doi.org/10.1007/s00704-023-04634-7.

A key question arising from the extreme heat wave of June 2021 in the Pacific NW was the role of anthropogenic forcing. In the following paper, a detailed study of event was carried out (some data for which was generated as part of the current project) it was demonstrated that a unique combination of weather patterns created the situation for the extreme heat that were essentially unrelated to extra GHG forcing (though GHGs could have added one or two degrees of the 20-degree anomalies).  In fact, climate model forecasts for the next few decades of this region suggest there will be a lessening of the chances of this synoptic pattern that created this event.

Mass, C., D. Owens, J. Christy, and R. Conrick, 2024: The Pacific Northwest heat wave of 25-30 June 2021: Synoptic/Mesoscale conditions and climate perspective.  Weather and Forecasting, 39. DOI: 10.1175/WAF-D-23-0154.1.

The increasing concentration of CO2 in the atmosphere is the dominate agent for increased forcing of the climate system.  Understanding the time-evolving budget then of CO2 will allow more precise estimates of atmospheric forcing.  In Spencer 2023, the author developed a CO2 budget model forced with human emissions and ENSO activity which very closely matches the yearly Mauna Loa, HI, CO2 measurements during 1959-2021.  Contrary to previously published results, it was found that there is no decreasing trend in the CO2 sink rate of 2.02% of the yearly excess over 293.6 ppm.  As a result, projections of CO2 emission results in model CO2 levels will be well below the IPCC RCP8.5 scenario through 2100, supporting the claims recently made in the IPCC AR6 that the RCP8.5 (and its related predictions) scenario is implausible. 

Spencer, R.W., 2023: ENSO impact on the declining CO2 sink rate.  J. Marine Sci. Res. Oceanography. 6(4), 163-170.  ISSN: 2642-9020. https://www.opastpublishers.com/open-access-articles/enso-impact-on-the-declining-co2-sink-rate.pdf.