well since time and all other dimensions are only relative, time as well as spacial dimensions can never change.  Really the only thing that changed is the location of the earth relative to the sun, now our orbit is slightly shorter and as a result our measurement of time is "off".
Since we can only perceive 3 dimensions and our movement in the fourth (time) is linear, to measure time we do so in terms of the 3 spacial dimensions.
Don't even get me started on time travel...