Mega companies push towards greener practices. Be it for better PR, energy cost reductions or good old fashioned ethics, does the reason even matter anymore?

Office Depot took a huge jump towards efficiency by lowering its carbon dioxide emissions by 10 percent in 2006. The company says it reduced energy consumption by retrofitting its lighting and adding light sensors that automatically turn off lights when areas like bathrooms and break rooms are unoccupied. Plus, it added high-efficient heating, ventilation and air conditioning units.

It seems like such a simple and obvious idea – why aren't all big stores doing this? Especially for all those big boxes just being built - these types of practices could be added at the start instead of retrofitting old stores later.

Maybe programs like the Environmental Protection Agency's (EPA) Climate Leaders Program, which includes companies like Office Depot, 3M and Gap, Inc. will inspire more to jump on board. The program allows companies to set a corporate-wide greenhouse gas (GHG) reduction goal and inventory their emissions to measure progress. They then report their inventory data to the EPA, which records their efforts.

Meanwhile, other big companies like Nike have received some publicity about their environmental efforts by participating in other programs, such as Climate Counts . The nonprofit organization funded by Stonyfield Farm, Inc. aims to encourage consumers and companies to take action on the climate crisis.