CarbonVisuals [carbonvisuals.com] is the "world leader" visualizing carbon dioxide emissions and other greenhouse gases.
Accordingly, CarbonVisuals have already developed several visualizations that aim to make such emissions feel more real, and in particular more graspable, as it compares the physical dimensions of several tons of CO2 emissions to everyday objects.
For instance, the CO2 emissions of the city of New York has been represented as a huge mountain of blueish balls - each basically representing 1 ton - that overgrow a 3D virtual city model of New York, while the according emissions statistics of its buildings has been turned into life-size - or huge-size - bar graphs. Alternative renditions, ranging from the level of a city- to that of a single potato, exist as well.
Watch the movies below.