Spring began three weeks earlier than usual in America yesterday with clocks moving forward one hour by order of the US Congress, which is convinced that the change will cut energy consumption.

The decision to bring forward the start of Daylight Saving Time (DST) — known as “summer time” or BST in the UK — from its traditional date on the first Sunday of April has been fraught with controversy.

Orthodox Jews argued against it because they must wait until dawn to say morning prayers. So did the airline industry, cautioning that it would throw its international schedules into chaos by putting it out of synch with Europe. And the National Sleep Foundation (there is a lobby group for everything) condemned Congress for robbing Americans so early of an extra hour in bed.

The cost to US businesses, which have hastily introduced software “patches” protecting their systems, has been estimated at up to $2 billion.

This morning some outlets of the Caribou Coffee chain are offering to add an extra 40 milligram shot of caffeine free into the cups of commuters.

But now the evenings are lighter and will stay so for an extra week until November 4, partly to make streets safer for Hallowe’en. Supporters predict that the change will mean fewer car crashes and less crime. But best of all, they say, is that it will help to save the planet.

On these grounds Ed Markey, the Democratic congressman, sponsored an amendment to the 2005 Energy Bill. He said that it would save $4.4 billion in fuel bills over the next 13 years and avoid the need to build more than three large electric power plants.

The reduction in energy consumption would, he said, stop America pumping 10.8 million tonnes of carbon emissions into the atmosphere by 2020.

The theory is that most people sleep through early morning daylight but guzzle energy in the evenings. But Mr Markey’s figures were based on a 30-year-old study by the American Council for an Energy-Efficient Economy, before round-the-clock air conditioning became a standard feature.

However, some economists have cited what happened in Australia when DST was introduced two months early in 2000 to increase daylight for the Sydney Olympics, when the reduction in evening peak load energy use was negated by a sharp rise in the morning.

In the UK there was a recent attempt led by Tim Yeo, the former Tory minister, to move clocks forward an hour the whole year round. This was blocked by Scottish MPs, who argued that the change would mean that people in the North would have to work for long hours in morning darkness. Environment ministers also claimed that moving clocks forward would result in a net increase of about one per cent in carbon dioxide emissions.

Into the light

— About 70 countries use daylight saving time of some kind. China, India and Japan are exceptions

— In the Second World War, Britain adopted Double Summer Time to save energy. Clocks were put two hours ahead of GMT during the summer and remained one hour ahead of GMT though the winter

— Until 2005, Israel regularly changed the date that it switched to DST. Religious politicians believed it should end before Yom Kippur

Source: California Energy Commission; US Department of Transportation; webexhibits.org

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