FoxClocks. Timely News.

On March 11^th much of the United States and Canada sprang forward into Daylight Saving Time (DST) three weeks earlier than usual. Because of this, as I write, DST is in force in both North America and Australia/New Zealand, while ’summer-time’ doesn’t start in Europe for another two weeks.

The US changes are a result of the US Energy Policy Act of 2005, while Canada as well as Bermuda, the Bahamas, the Qaanaaq (Thule) area of Greenland and the French collectivity of Saint-Pierre and Miquelon (the last remnant of New France) pragmatically followed suit. There is much speculation as to the havoc this change will wreak and the rewards we will reap with this first major change to North American DST rules since the advent of the personal computer. Worst-case scenarios draw parallels to Y2K, and it does seem fairly likely that, given the lack of lead time, some systems somewhere will fail. Calendaring applications seem particularly vulnerable, as do devices such as routers. According to a straw-poll at Computerworld’s Premier 100 IT Leaders Conference conducted on March 5^th, only about half of attendees had finalized system changes. Microsoft, apparently, was still issuing patches.

It seems remarkable that software should be so difficult to update: Sun’s Java has hard-wired DST rules, for example, as do earlier versions of Red Hat Linux, which require an update to a core system component (glibc). At best, the 2007 changes could be a wake-up call for software developers: DST rules change all the time. The US, for example, has made sweeping changes to its rules roughly once a decade until recent times, and state-wide (and even municipal-level) changes occur relatively frequently even now. On a global level, hardly a month goes by without a country-level change to DST legislation; some countries, such as Brazil, announce the start date of DST annually.

The benefits of an extra hour of daylight in the evening - and one less in the morning - may or may not include reductions in energy consumption, traffic accidents and crime rates (the explicit goal of the US legislation is to reduce energy consumption by 1%). David Prerau, writing in the New York Times, seems confident that the changes will provide these benefits. Others are not so confident. The California Energy Commission’s Demand Analysis Office’s paper Electricity Savings From Early Daylight Saving Time (pdf) concludes that “There is no clear evidence that electricity will be saved from the earlier start to daylight saving time on March 11, 2007…”. The University of California Energy Institute’s paper Does extending daylight saving time save energy? Evidence from an Australian experiment (pdf), which parallels an experiment in early DST in Australia in 2000 with the 2007 North American changes, is less optimistic still: “… while extending DST does reduce electricity consumption in the evening, the increased demand in the morning cancels this benefit out. We statistically reject electricity savings of 1% or greater at a 1% significance level.”

Cynics suggest that the DST changes are a poor substitute for a real energy conservation policy, and point out that more daylight in the evening means more shoppers venturing out to the mall in their SUVs.

This entry was posted on Monday, March 12th, 2007 at 19:38 GMT and is filed under FoxClocks. You can follow any responses to this entry through the RSS 2.0 feed. You can skip to the end and leave a response. Pinging is currently not allowed.