Here it is in a nutshell. The sun, volcanoes, and greenhouse gases affect the climate, and any combination of the three are always in play. Right now, the climate is warming, but scientists say that both solar and volcanic activity are low. Water vapor and carbon dioxide (CO2) are the largest parts of the greenhouse gases, and of the two, only CO2 is rapidly increasing. The great majority of CO2 comes from nature through the decay of organic matter, and nature (oceans, trees) also absorbs the majority of the CO2. The only causes of rapidly increasing CO2 are coming from burning fossil fuels and the cutting down of trees, which reduces the absorption of CO2 by nature. This is what the climate scientists are saying and they are the only people qualified to assess the climate crisis. But, George Carlin was right as well. The planet will "shake us off like fleas" with a climate catastrophe if we don't do anything to deal with it.