Apart from the fact that sips likely generate more pollution than cars [1], it's seems very plausible that he would generate more of it being stuck in a traffic jam while getting to work than he did during these holidays.
He also didn't probably use as much electricity as you do at the moment which is likely generated mostly in non environmentally friendly way. Ignoring the fact that many parts of your equipment came on ships from China. From factories which generate a lot of pollution.
Also, if you want to be perfect better-world-optimizer, it is really hard. Even if the earth would get ever slightly more polluted by this single car, the impact of thousands of people reading the story could still be positive. It makes them think about nature, probably slightly increases their well being, and so on.
1. http://www.dailymail.co.uk/sciencetech/article-1229857/How-1...