a researcher with 40+ years expertise, and no reason to lie:
Look at the NOAA annual mean growth rate of CO2 chart covering 1960 through 2016 at Mauna Loa observatory.
Notice that CO2 growth rate dropped to .28 and .48 ppm for years 1964 and 1992.
How come? Did people suddenly burn less coal and oil those years?
No, it was Mt. Agung (1963-64) and Mt. Pinatubo (1991-92) blasting about one cubic mile of ash into the air to a height of some 22 miles. This causes a shading/cooling effect on the ocean which then expels less CO2.
Water vapor, a greenhouse gas, traps about 1,375 times more heat than man’s CO2. That’s based on a 1% global atmospheric water vapor content; however it can at times go up to 4% in places.
The thing about water vapor is its variability from day to day and place to place over the Earth; and that’s a big problem for climatologists when trying to get climate models to work.
Even a somewhat small up or down change in the massive quantity of water vapor may release or absorb far more heat, and therefore have more effect on temperature, than would a doubling of our current tiny CO2 level.
Oceans have a huge effect on water vapor level depending on the amount of cloud cover blocking the sun’s energy, and what the 40,000-mile “tank heater” (under-sea volcanic mountain chain) happens to be belching out at any given time.