The temperatures in the summer of 2023 were due to a sharp increase in solar radiation
The media has reported record-high temperatures for the summer months of the past year. Climate change has been blamed, which the IPCC claims is solely due to the increase of greenhouse gases. Nowhere has there been any news that the Earth received about 3 W/m2 more solar radiation in August 2023 than in the first half of the year 2000. According to the IPCC, human-induced radiative forcings in 2019 were 2.7 W/m2, which caused a temperature increase of 1.27 °C compared to 1750. Even according to IPCC science, the amount of solar radiation is a more significant factor than greenhouse gases.
The increase in solar radiation received by the Earth has not been due to changes in solar activity but to changes in the atmosphere. The most likely reason is a decrease in the amount of low cloud cover. The overall situation can be seen in the figure, which shows the measured temperature and the temperature calculated using the model from 2001 to August 2023.
In the figure, the red curve is the monthly GISS temperature, and the simple climate model of the author is the black curve. The green curve is the temperature change caused by carbon dioxide calculated according to the author. The effect of the ENSO effect is a blue curve and the net amount of solar radiation received by the Earth is a yellow curve. The latter has been calculated according to the measurement results of CERES satellites, calculated as the difference between the radiation from the Sun and the radiation reflected by the Earth. An accurate description of the author's simple climate model can be found in this article: https://journalcjast.com/index.php/CJAST/article/view/3586/7173
It is easy to conclude, even when viewed with the eye, that changes in global temperature, especially after 2014, are caused by the solar radiation changes and the ENSO effect. Carbon dioxide does not affect annual and monthly temperature changes. El Nino, which has been developing over the past summer, has not yet affected global temperatures, as its global temperature effects come with a delay of about six months. The high temperatures of recent months are solely due to a sharp increase in solar radiation, the values of which are currently known until August 2023.
The figure below is a copy from the CERES net pages: https://ceres-tool.larc.nasa.gov/ord-tool/jsp/EBAFTOA42Selection.jsp showing the change of 3 W/m2 from 2000 to August 2023.
Dr. Antero Ollila