Mercury News: City residents are well on their way to shrinking their carbon footprint to a size not seen in 20 years, since before the 1989 Loma Prieta earthquake. Since 1996, Santa Cruz residents have reduced the amount of carbon dioxide pollution they create annually by more than 110,000 tons, from 455,187 tons in 1996 to 344,230 tons in 2008, according to city officials. A carbon footprint is a measure of the impact certain activities have on the environment. It relates to the amount of …