KEY POINTS:
New Zealanders will join millions around the world tonight in switching off the lights to help save the planet.
Among them will be one couple who aren't letting the biggest milestone of their lives stop them taking part.
Christchurch is the first New Zealand city to
join Earth Hour, when as many lights and power-using items as possible will be shut off for an hour from 8pm to inspire people to save energy and combat climate change.
Auckland will not be left out - the lights of the Sky Tower will go down for an hour in the city's most visible contribution.
Christchurch couple Julia Panfilo and Myli Hunt will be making sure their wedding day fits in with the spirit of Earth Hour.
At 8pm, when everyone else powers down, the lights will be switched off at the couple's wedding reception and guests will listen to speeches by candlelight.
"Some of the guests know ... they are pretty excited," Miss Panfilo said.
"Just being part of the whole thing feels good. We are trying to be environmentally minded because we want our kids to be able to enjoy this planet."
The Earth Hour concept was pioneered in Sydney last year when 2.2 million Sydney-siders and more than 1100 businesses turned off their lights, plunging buildings and landmarks such as the Harbour Bridge and Opera House into darkness for an hour.
This year, it has become a global event, and cities from San Francisco to Copenhagen will turn off their lights.
In Christchurch, Cathedral Square, city facilities, businesses and private homes will be plunged into darkness.
Turning off the lights at about 70 facilities, including an art gallery, libraries and leisure centres, is a big logistical exercise, says city council spokeswoman Shirley Went.
` "Everything is on timers. And because we consider Christchurch to be a beautiful city, a lot of our statues and trees and old buildings are lit. It's not like when you are at home and can just switch off the lights. A lot more thought has to go into this."
Street lighting and traffic lights will remain on for safety.
Many bars and restaurants in the city are taking advantage of Earth Hour to hold special parties or offer meals by candlelight.
Christchurch Airport will conserve electricity for an hour by dimming the lights in its international terminal and switching off all non-essential power.
EARTH HOUR
* People around New Zealand are being encouraged to turn off their lights between 8pm and 9pm tonight for Earth Hour and commit to a 5 per cent energy saving.
* Christchurch will join cities such as Copenhagen, Toronto, San Francisco, Chicago, Melbourne, Dublin and Tel Aviv in the event.