Government buildings, Leinster House, the Custom House, and the Four Courts were blacked out.
Countrywide, the Rock of Cashel, the most visited heritage site in Ireland, was plunged into darkness as was Cahir Castle, Ormonde Castle, Donegal Castle and Trim Castle in Co Meath.
Environmentalists have hailed the one hour switch-off as a big success and renewed their calls for nations to urgently tackle climate change.
“The world said yes to climate action, now governments must follow,” the World Wildlife Fund said yesterday, a day after hundreds of millions of people worldwide followed its call to turn off lights for a full hour.
From an Antarctic research base and the Great Pyramids of Egypt, from the Colosseum in Rome to the Empire State building in New York, illuminated patches of the globe went dark last night to highlight the threat of climate change. Time zone by time zone, nearly 4,000 cities and towns in 88 countries dimmed non-essential lights from 8.30pm to 9.30pm.
And we in Ireland played our part with all cities, as well as thousands of individual households, taking part in the initiative.
WWF called the event, which began in Australia in 2007, “the world’s first-ever global vote about the future of our planet”.
“Saturday’s message from the masses was loud and clear: Delay no more, real action now!” Kim Carstensen, the leader of WWF’s Global Climate Initiative, said.
Earth Hour officially began when the Chatham Islands, 800km east of New Zealand, switched off its diesel generators. At Scott Base in Antarctica, New Zealand’s 26-member winter team resorted to minimum safety lighting and switched off appliances and computers.
In Australia, Sydney’s glittering harbour was bathed in shadows as lights dimmed on the steel arch of the city’s iconic Harbour Bridge and the nearby Opera House.
As the sun moved west, the Great Pyramids and Sphinx in Egypt darkened.
So did the Acropolis in Athens and the Colosseum in Rome. In Paris, the Eiffel Tower, Louvre and Notre Dame Cathedral were among 200 monuments and buildings that went dark.
The Eiffel Tower, however, only extinguished its lights for five minutes for security reasons because visitors were on the tower.
In Dublin, Cork and other parts of the country private businesses and civic buildings took part in the switch off.
The celebration then crossed the Atlantic, where crowds at New York’s Times Square watched as many of the massive billboards darkened. The Majestic Theatre marquee at the home of The Phantom of the Opera went dark, along with the marquees at other Broadway shows.
“Earth Hour has always been a positive campaign,” said Earth Hour executive director Andy Ridley.
“It’s always around street parties, not street protests, it’s the idea of hope, not despair.
“And I think that’s something that’s been incredibly important this year because there is so much despair around.”