Apple put its big new headquarters in Cupertino, which doesn't have any housing available for all the people working there. Therefore, the majority will be forced to drive long distances to work, in dirty, CO2-heavy automobiles. Apple could have used its financial leverage - a third of Cupertino's tax revenue - to force the city to stop blocking all new housing construction, reducing commute distances. Alternatively, it could have placed its headquarters somewhere else - somewhere with either more housing, or enough density to support public transit, or a city council that isn't obsessed with enriching homeowners by making a housing shortage as bad as possible (or all three). Apple chose not to do either of those things, so all of those CO2 emissions are its responsibility.