The world is not made up of corporations. The huge majority of people work in small business. So, that's the small business that should be trying...
And it's quite easy. For instance, there are electricity provider that guarantee that 100% of the energy you use is compensated by green energy fed to the grid (and some even exclude nuclear). They a little bit more expensive, but it's something like 10% extra cost. Small business can perfectly decide to use them and that's already something positive.
Likewise, my girlfriend works in a business with around 100 people. They make trips to visit their customers on a daily basis. Yet, the Paris agency decided that public transports were good enough. So they sold the company car and decided to use only the train - car renting is an exception.
And this actually saves them money. With frequent users cards, train is not that expensive. Moreover, when someone spends 4 hours in a car, that a total loss of production. But when someone spends 4 hours in a train, he can work most of the time. When someone makes 2 or 3 trips during the trip, that's a lot of recovered work hours !
There are a lot of adjustments small business can do : investing in energy efficient lights (LED), not using air-conditioning all the time, using computers and screens that are energy efficient... And in the end, all that means less energy usage, so lower costs...