Earth Hour: A voluntary blackout tonight for environmental issues by over 7,000 cities in 154 countries

London: Lights will be switched off in homes, offices and famous landmarks at 8.30 p.m. Saturday for an hour to mark WWF's annual Earth Hour.

Millions of people around the globe will participate in the celebration of the eighth edition of the Earth Hour to show their support for environmental issues ranging from deforestation to energy efficiency, The Guardian reported.

The Intergovernmental Panel on Climate Change (IPCC) is set to launch its latest report in Japan Monday outlining how global warming is affecting wildlife, food supplies, water and the weather globally.

"It's fortuitous timing that as millions of people take part in WWF's Earth Hour, the world's leading scientists release the latest IPCC report, which highlights the various impacts of climate change," Colin Butfield, director of public engagement and campaigns at WWF-UK, was quoted as saying.

"The significance of these two events is massive. Climate change is the biggest environmental threat facing our planet, it's real, it's happening right now, and we need to act fast," he added.

World famous landmarks which will dim their lights to join in the celebration of the Earth Hour includes the Eiffel Tower in Paris, Houses of the British Parliament, Buckingham palace, Tower Bridge and the London Eye in Britain, the Empire State building in New York, the Kremlin and Red Square in Moscow, Burj Khalifa in Dubai, the Bosphorus Bridge in Turkey and the Brandenburg Gate in Berlin. Even the iconic Howrah Bridge in Kolkata would go semi-dark for an hour.

The Earth Hour, launched in 2007 in Australia, has become the world's biggest environmental event.

Last year, more than 7,000 towns and cities in 154 countries were part of this event.

WWF in 2014 is launching Earth Hour Blue, a digital crowd-funding and crowd-sourcing platform that enables participants to help raise funds and take action on various environmental issues.

Projects open for donation range from a solar-lighting project to reduce human-wildlife conflict in India to teaching fisherman in the Philippines how to build boats without using wood from the local forests.

"For us the symbolism or turning your lights off will always be important. But the big thing for us has always been how to push it beyond the hour," said Earth Hour's CEO and co-founder, Andy Ridley.

"The stage we're at now is to make it really easy for people from their handset, tablet or laptop to be able to do something pretty immediate to make a difference. That's the holy grail for us - building a global collective movement, far beyond the event, where the event becomes a kind of inspiration but the movement is really the essence of it."

According to reports by the WWF, the awareness and funding generated by Earth Hour has led to several significant conservation successes in the past few years.

Argentina in 2013 used Earth Hour campaign to pass a senate bill for the creation of a new 3.4 million-hectare marine reserve while half a million trees were planted in Uganda.

Meanwhile, WWF announced Saturday that it has awarded the title of Global Earth Hour Capital 2014 to Cape Town in South Africa.

"The city is recognised for its ambition and pioneering actions to combate climate change in its effort to bolster quality of life for its citizens. Cape Toen succeeds last year's winner Vancouver, Canada," a WWF statement said.