Volume 4 consists of two regular issues, Vol. 4.1 and 4.2. An additional issue, Vol. 4.3, contains all presentations on the CLINTEL Climate Conference in Prague. Vol. 4.4 is planned for contributions of the Climate Conference 2024 in Mölndal, Sweden.
This issue, Vol. 4.2, starts with an article of Dai Ato, who has rigorously examined the impacts of sea surface temperature (SST) and fossil fuels on the atmospheric CO₂ level using a multivariate regression analysis. This study demonstrates that the independent determinant of the annual increase in atmospheric CO₂ concentration was SST, which shows strong predictive ability, while human CO₂ emissions are irrelevant.
Moritz Büsing has investigated the ageing of weather station housings with its influence on the temperature measurements. Due to many different state-of-the-art homogenization algorithms, which are adding up each time a weather station is renovated, renewed, or replaced, this results in a substantial systematic error. An in-depth analysis of the weather station data sets (homogenized and non-homogenized) confirms the presence of this systematic error. Corrections reduce the calculated warming of the land surface temperatures since 1880 from 1.43 °C to 0.83 °C. An estimate of a less conservative correction even suggests only 0.41 °C.
Demetris Koutsoyiannis discusses the relative importance of CO2 and water for the greenhouse effect, using a detailed atmospheric radiative transfer model. He derives macroscopic relationships of downwelling and outgoing longwave radiation with their respective partial derivatives. From this he infers that CO2 doesn’t contribute more than 4% – 5% to the greenhouse effect, while water and clouds dominate with a contribution of 87% – 95%. The minor effect of carbon dioxide is confirmed by the small, non-discernible effect of the recent escalation of atmospheric CO₂ concentration from 300 to 420 ppm. This effect is quantified at 0.5% for both downwelling and outgoing radiation.
Frans Schrijver studies the impact of global greening in terms of gross primary production on the natural atmospheric CO₂ level. The total mass of CO₂ in the atmosphere is equal to the yearly uptake of CO₂ (down flux), multiplied by the average time, CO₂ remains in the atmosphere (residence time). The biological processes of photosynthesis and respiration are by far the most important components of the fluxes to and from the atmosphere. Since preindustrial times the down flux has increased by 29% and the residence time by 16%. Together they fully explain the recent CO₂ rise, without assuming different behaviors for human-generated CO₂ compared to natural CO₂ and without the need for an ad-hoc model with multiple residence times.
In a debate paper Ad Huijser presents his view of greenhouse feedbacks, which he explains as “intrinsic properties of the Planck feedback parameter.” From this he concludes that climate feedbacks are not effects induced by forcings, but constitute our climate. So, independent from the origin of a disturbance, our climate will always respond according to the Planck feedback parameter, which he just sees as difference between the surface feedback parameter and the sum of climate feedbacks.
Finally, this issue contains a note from Zdirad Žák to a comment of F. Engelbeen on historical data of E.-G. Beck. Due to a consistency of Beck’s and Callendar’s data Žák asks: Has not already come the time to change our mind about a background level of 280 ppm?
We hope that the above contributions will stimulate our readers to a further critical discussion of climate science, and we wish interesting reading.