The advancing warming of Earth climate has largely been influenced by natural causes, i.e. increased Solar activity and decreasing volcanic activity on Earth. It still remains unknown which part of the warming process results from the increased amount of Solar energy reaching Earth surface, and which is being caused by the anthropogenic part of atmosphere’s greenhouse effect. The facts speaking in favour of natural factors include synchronic changes of mean air temperature on the Northern hemisphere between 1856 – 2002, mean consecutive 11-year Wolf numbers, and the location of mass centres of the four biggest planets in our Solar system.
The theory of natural causes of climate warming is also backed by synchronic changes in carbon dioxide concentration and paleotemperature within the last 160,000 years and 450,000 years, recreated based Antarctica ice cores. Warmings occur every 100,000 years. They are triggered by increased Solar radiation in large geographic latitudes resulting from changes in Earth orbit and Earth axis slant (according to the already accepted Milankovic theory).
“Parallelism” of changes in CO2 concentration and paleotemperture shows that the atmospheric content of carbon dioxide is shaped by the amount of Solar radiation reaching Earth – through shifts in ocean waters temperature. It is more credible to claim that “CO2 concentration in atmosphere rises along with the amount of Solar radiation reaching Earth surface (i.e. when it is warmer).”