Google changes the logo for each day to represent an event that is celebrated on that day. Earth hour was about switching of your excess lights.
What it does highlight though is your non existing interest in environmental issues. It has been widely advertised on the internet and it surprises me you did not know about it.
Google also does a free service of news feeds to your e-mail address. The same in many other browsers or e-mail providers. Maybe time to give one of them a try just so you can keep up with global events.
I missed that thread & the 'Earth Hour' advertising seems to have made no impact in the UK. I think it would have been doomed to failure here anyway as 9:00am GMT is when most office workers arrive & make their morning cup of tea.
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I didn't have a really important life, but at least it's been funny (Lemmy Kilminster 1945-2015)