https://thsresearch.files.wordpress.com/2017/04/ef-data-research-report-second-editionfinal041717-1.pdf
That simple model explains 75% to 90% of the annual average temperature variability using only four influences (CO2, El Nino, volcanoes, and solar energy).
Natural factors -- El Nino oceanic activity, solar energy, and volcanic activity, explain the Earth’s tropospheric and surface temperatures, and atmospheric CO2 is not important.
The model uses econometric simultaneous equation parameter estimation techniques.
It also uses balloon temperature datasets starting in 1959.
It uses satellite temperature datasets starting in 1979.
At least 75% of the temperature variability since 1959 can be explained WITHOUT using CO2 as an explanation.
These results contradict the findings of the UN's IPCC, which claims the primary cause of global warming is CO2 -- a claim made about CO2 with no scientific proof.
The current very complex global circulation models (GCMs) are not based on a thorough understanding of climate change.
They can't be, because the understanding of climate change is very weak.
The GCMs simply assume CO2 controls the climate, with no evidence CO2 ever controlled the climate, at any time in the past 4.5 billion years of earth's existence.
The conclusion that CO2 controls the climate must be wrong because it caused 97% of climate models to predict warming that averaged three times more than the actual warming since 1975.
And none of the GCMs predicted the flat average temperature trend we had between 2000 and 2015.
Leftists claim a significant increase in CO2 will result in dangerously higher surface temperatures and runaway warming.
But CO2 levels were higher than today for almost all of the past 4.5 billion years, and there was never any runaway warming in the past.
Runaway global warming from CO2, or anything else, is a leftist fantasy.