Not only the engine rules have changed, but the FIA has also dramatically reduced the amount of downforce.
But although downforce levels were similarly attacked in 1998 and again in 2009, Green said that the huge changes for 2013 are "crucially different".
"The downforce loss is in the same region and is quite significant," he told Germany's Auto Motor und Sport.
"But this time the drag has also been dramatically reduced, where in the past the drag stayed the same while downforce was going down."
Asked if that means top speeds will be higher in 2014, Green agreed: "Yes. I expect the cars to be about 15kph faster."