system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why is USA Daylight savings time starting tonight when the UK won't see it for another 3 weeks?
gpt
The US government extended DST in 2005 because a dept of energy study said it would save energy.

After the change,  they measured and found energy consumption dropped 0.03% compared to the previous year.  So it wasn't really worth all the bother of being out of sync with the rest of the world.