CLEAN: Billion people invited to switch off lights for 'Earth Hour'

The video discusses the global effort to unite for the future of the planet, highlighting how millions of people across various cities and continents will come together to speak with one voice. It also includes expressions and reflections on this collective action.

What emotions or sentiments are conveyed in the text regarding the future of the planet?

What is the significance of the phrase 'one voice' in the context of the text?