First off, we had a local Mountain climber who noticed locally receding glaciers enough that he started privately measuring in 1968. No one believed him, glaciers were "forever" and "always grew", not receded.
I don't think that you have to think very hard to realize that in the past 50 years, we've increased individual household electricity use. Heck, back in the 1940's and 1950's there were still folks that weren't hooked up to the grid due to accessibility as opposed to choice.
Many businesses do what is called a thermal load study during construction and when placing equipment. It is not so much aimed at reducing the emitted heat from the equipment as it is to calculate required air flow and air conditioning/cooling requirements. More so than the actual heat given off, the things we do to then cool the interior environment down contributes more to global warming. This is all the more so as we move to energy efficientt, sealed buildings with little or no exterior air flow outside of what is sucked in and moved by fans.
A number of our current electronic devices have some type of a clock, slumber, or warmed up and ready to go, state that uses electricity even when it is "turned off" or not operational. There is a growing movement, at least residentially, to physically power these items down either by pulling the plug at the wall or buy plugging them into a power strip then turning off the power strip. Individuals often notice a difference in their power bills when they do this. - If they've reduced their energy consumption enough to notice it on their power bills, it cannot be insignigicant. The more people we can get to do this, the better off we will be. Obviously, more economically marginal folks seem to be doing this first as much if not more so as an economic savings. They tend to have fewer electronic devices. The trick is to get those of middle and higher middle income with so many more devices to do the same.
Likewise, I know that in our house with no air conditioning and increased summer heat - Turning off lights(even our CFLs), appliances, and even the coffee pot while reducing the use of heat giving devices and increasing the use of lower heat giving devices - certainly makes a comfort difference. If we were running air conditioning, I'm sure that doing these things would reduce the amount/length that it would operate enough that we could notice it on a bill.