My hypothesis is that human activities have had minimal effect upon climate. The Milanković cycles alone have produced periodic glaciation and brief periods of intense warm climate between glaciation.
During each warm period, one reaches the point that we are at now, where permafrosts are melting and releasing copious amounts of methane, a far more potent greenhouse gas than carbon dioxide. As the greenhouse effect intensifies, we reach the peak interglacial temperature, which we call the Climatic Optimum. Forests grow in what were formerly arctic tundra regions. The tropical rain forests march Northwards. Hot deserts form around the equatorial regions. All quite naturally.
The Climatic Optimum ends with an abrupt temperature decline - perhaps caused by a prolonged intense wildfire season that fills the atmosphere with smoke. Carbon capture is maximized and sea levels rise, forming peats and trapping carbon where it cannot decay. Widespread plankton die-offs take place in the oceans, and layers of dead animal and plant matter form on the ocean floor. In millions of years and after many more such Milanković cycles, new deposits of coal and petroleum exist in the Earth's crust.
Mankind can do little to slow or speed up or lessen or increase what is happening. We didn't cause them, orbital mechanics caused them, the slowly interacting cycles of precession, obliquity, and eccentricity that in turn cause changes in solar insolation.
Even if mankind's activities hastened or intensifies the natural climate cycles, we are helpless to change them. The slow march of the planets around the Sun will continue, and with it the changes in insolation.
Nevertheless, it is a genuine emergency that we are running out of FF's to burn for energy. I advocate using the remaining supplies of FF's to transition to other forms of energy production. I take this position for the benefit of the human species, not because I care about the fate of this ball of dirt that is our temporary home.