Your linked article/source is a biased, pro-ACC/AGW source. As the saying goes 'has a dog in the fight'.
The situation and math is rather simple.
At @410ppm of CO2 and what is about 1ppm of Methane, the ratio of both to total atmosphere composition, less water vapor, is about 1/2,500.
If we have, say, 2,500 pennies (that's fifty rolls of fifty each) all at 70 degrees F. bunched together in a pile, and we take ONE penny out of the pile and heat it up to 80 degrees F.; then drop it back into the middle of the other 2,499 pennies, it will NOT heat the whole pile to 80 degrees. Not even to one degree more (71). It will transfer some small amount of heat to a few that are in contact with it, but only a few, barely a degree or two, and that will quickly fade via the low temprature of the rest of the pennies absorbing portions of it as it dissipates.