Thinking about the correct use for the correct tool, based on efficiency. For instance, it is very carbon intensive to bring together the materials and then produce a backhoe. The shipping from factory to customer is another great intensive act - the truck uses gas, but the highway had to be built for the truck to drive on. Then there is the operation and eventual lifecycle end of the backhoe. All greatly intensive uses of carbon.
However, the backhoe is so efficient at what it does, maybe it cancels all that out?
Take that idea and apply it to small powered tools - like a lawnmower. The same relative amount of energy intensivity happened to put that mower in your hands, but the tool's efficiency ratio compared to doing it by hand isn't as much.