Guardian: At 8:30pm today the luminous face of Big Ben will go dark. Next door, the houses of parliament will switch off all its lights too, along with thousands of landmarks, buildings and people around the world in a global gesture of solidarity in the fight against climate change. From the international dateline, Earth Hour starts in New Zealand’s Chatham Islands and will conclude in Honolulu. Passed like a baton around the planet, cities including Sydney, Hong Kong, Singapore, Moscow, …