Earth Hour 2011, WWF’s global event is coming up again this Saturday, March 26th.

Across the UK and world people, businesses and iconic buildings will switch off their lights for an hour at 8.30pm local time.

Last year Earth Hour saw hundreds of millions of people across 3,000 cities and towns in 83 countries take part and send a clear message to governments worldwide that climate change needs to be tackled urgently.

But, this will only be possible with enough support and so WWF are calling on everyone to do their part, to get involved and to tell as many people as possible about Earth Hour.

Participating is as easy as signing up or Liking the Earth Hour Facebook page and switching off for an hour.

If you have a Twitter account or are on Facebook you can spread the word about Earth Hour by donating a tweet or status update and you can ask your friends, family and colleagues to get involved too.

If you want to do more then there are a number of other great tools and resources, including:

• The Earth Hour UK & Ireland county signup challenge which pits county against county to see which part of the British Isles has the most people signed up to Earth Hour 2011
• The now famous Earth Hour light switch widget to embed on your blog
• An Earth Hour Twibbon to show your support via Twitter

Finally, this year we’re looking to take the campaign ‘Beyond the Hour’ by inviting people to think about the ways in which we can make a difference once the lights come back on.

This could include thinking about ways to make your home more energy efficient, making sure you choose wood and paper products that have been responsibly sourced or by taking part in the WWF’s campaign to make sure the UK government’s Energy Bill really makes a difference.

So there you have it, everything you need to know about Earth Hour 2011. Every contribution, no matter how small you think it might be (even re-tweeting this post would help!), is important, so please help us and show your support.

The more sign-ups we get, the more we can show governments around the world how seriously people now consider global warming to be, and how loud their voice is on this urgent issue.