One way is to consider the value of services that the environment provides. Nature provides services like pollinating crops, purifying water, protecting us from storms, producing fish, and many many more - services that we depend on. These services are provided to us for free!
The value of these services in 1997 was $125 trillion (compared to the world's GNP of $75 trillion)
In business we consider the cost of services that we need when calculating our profit margins, but I doubt the value of natural services are considered and why should they be...these services are our birth rights as residents of earth. That is, until these services start to degrade. Since 1997, the value of the services the earth provides has decreased by $20 trillion, and where we have become dependent or have taken these services for granted, this has started to cost us money.
What comes to mind is the money we are spending on water, farming fish, property damage from storms, and how much will it cost us take over pollination if the Bee's disappear.
Take a long look at your balance sheet and see if any of these types of costs might be creeping in and eroding your profit margins.
Every business from mining to manufacturing, from farming to fashion, from entertainment to banking, from healthcare to technology all have financial stakes in the environment.