This year's 15th edition of Earth Hour highlighted the link between the destruction of the natural world and the increasing incidence of diseases, such as Covid-19.
Cities around the world have been turning off their lights for Earth Hour, with this year's event highlighting the link between the destruction of nature and increasing outbreaks of diseases like Covid-19.
Starting off the event, at 8:30 pm the skylines of Asian metropolises from Singapore to Hong Kong went dark, as did landmarks including Sydney Opera House.
The annual event calls for action on climate change and the environment, and this year, organisers said they want to highlight the link between the destruction of the natural world and the increasing incidence of diseases – such as Covid-19 – making the leap from animals to humans.
Experts believe human activity such as widespread deforestation, destruction of animals' habitats and climate change are spurring this increase, and warn more pandemics could occur if nothing is done.
"Whether it is a decline in pollinators, fewer fish in the ocean and rivers, disappearing forests or the wider loss of biodiversity, the evidence is mounting that nature is in free fall," said Marco Lambertini, director general of the WWF, which organises Earth Hour.
"And this is because of the way we live our lives and run our economies.
"Protecting nature is our moral responsibility but losing it also increases our vulnerability to pandemics, accelerates climate change, and threatens our food security."
In Singapore, people at the waterfront watched as skyscrapers went dark and in a nearby park, Gardens by the Bay, a group of futuristic-looking tree sculptures had their lights turned off.
🕣See our planet in a new light🕤— Earth Hour Official (@earthhour) March 26, 2021
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Just a symbol?
Earth Hour is about "more than just saving energy, it's more like remembering our impact on the environment," Ian Tan, 18, told AFP at the park.
But he was not convinced the event, which has been running since 2007, made much of a difference.
"One hour is not enough for us to remember that climate change is actually a problem – I don't really see (Earth Hour) as very significant," he said.
In Hong Kong, people at viewing points above the city watched as lights were dimmed on hordes of closely packed skyscrapers, while in the South Korean capital Seoul, the historic Namdaemun gate went dark.
In Thailand, Bangkok's ultra-popular CentralWorld mall counted down to 8:30 pm (1230GMT) before its exterior glass displays went dark for an hour – though inside, the shopping centre appeared to operate as usual.
Other landmarks that were due to switch off the lights to mark Earth Hour include the Eiffel Tower, the Colosseum in Rome and the Brandenburg Gate in Berlin, according to organisers.