"Please switch off your lights on 29th March at 8pm for 1 hour"
This will not only contribute directly in reducing global warming by non-generation of heat but also create awareness among the people about global warming & its effects.
After getting very good response in Sydney, where it started last year, Earth Hour has now spread across the world with 20+ major cities that have agreed to follow this voluntarily at their local times.
I understand that some of us have already begun following environmental friendly tips wherever possible in our daily life. However, following Earth Hour now would only add more to our contribution.
You may check this site for more details - http://www.earthhour.org/
So don't forget. 29th March. 8pm - 9pm, local times.