I too feel that we have impact, but not nearly planetary climate dictating impact. I suppose if things were utterly static, that might be the case. But they are not.
Like a single candle in a room, could heat it over time.
But not when doors are opening and closing, and the weather outside is changing all the time, sun going up and down, refrigerator turning off and on, etc.
Clearly there are large gaps in understanding to make worst case scenarios predictions. And I put zero trust in supercomputer simulations that lack the massive compelexities of planetary climate.
One problem with your candle analogy is the closed nature of the carbon cycle. We may note that the rate of injection of carbon into the cycle is small compared to the rate of the carbon cycle itself, but we also have to note that the carbon we are injecting has been sequestered in the ground for these many millions of years, and now is being loaded into the cycle in a “geological instant” as they say, and is bound to be a shock in one form or another to that cycle.
That is an excellent “layman’s” explanation!
"All of the greenhouse gases created by humans and added to the air since the Industrial Revolution began cause a heating equal to that of two 1-Watt bulbs over every square yard of Earth's surface." (A 1-watt bulb is a small "Christmas tree" bulb.)