Context:

Recently, US President-elect Donald Trump said he would make the best effort to end Daylight Saving Time (DST) in the US which he described as ‘inconvenient and very costly to the Nation.’

Daylight Saving Time (DST)

DST refers to the practice of resetting clocks ahead by an hour in spring, and behind by an hour in autumn. The result is that clocks show a later sunrise and sunset, leading to longer evening daytime. 

• For example, in the US, clocks are advanced from 2:00 am to 3:00 am, skipping one hour for DST. In the EU, clocks in the 28 member states move forward on the last Sunday in March and fall back on the last Sunday in October. 

A group of Canadians in Port Arthur (Ontario) were the first to adopt DST on July 1, 1908.

DST is used in the US, some European countries, and New Zealand and Southern Australia.

India and parts of Asia and Africa do not observe DST. 

Role of Earth’s Rotation

• The Earth revolves around the Sun in an almost circular orbit.
• It also rotates on its axis, which is tilted by 23.5° relative to its orbit around the Sun.
• This tilt gives us longer days in summer and shorter days in winter.
• DST ensures that the extra daylight is utilised efficiently. 
• DST is most beneficial in mid- to high-latitude countries (e.g., Europe, North America) where seasonal variations in daylight hours are significant. 
• Countries near the equator do not need DST due to low variations in daylight hours between seasons.
• Countries close to the poles also do not use DST as they see drastic changes in day and night. The north and south poles experience six months of daylight and six months of night in a year.
• DST is not always adjusted by an hour. For example, Australia’s Lord Howe Island adjusts by 30 minutes.

Merits of DST

• It gives people an extra hour of daylight in the summer. For example, children in schools have more outdoor playtime.
• The extra daylight hours lead to electricity savings due to extended natural light. 
• DST can benefit retailers and other companies who rely on longer daylight hours to boost sales and traffic through their locations.
• Extended daylight can reduce traffic accidents and pedestrian fatalities by improving visibility during peak commute times. 

Demerits of DST

DST can disrupt sleep cycles and cause health problems like increased risk of heart attacks.

• A study in the US found that DST increases the risk of heart attack by 25%, while a return to original times lowers the risk by 21%. 

It can cause disruptions in work schedules and financial transactions. 

Computers can lose valuable transactions or data when adjusting themselves to a new time. 

While DST benefits certain industries, others (e.g., agriculture) may suffer. Farmers often oppose DST as it disrupts natural schedules for livestock.