I don't think your assertions are correct. This article[0] is a bit old (2015), but it puts the number of SUVs on the road at 35%. There absolutely are things you can do, though obviously you, personally, aren't going to solve the problem. For example, skipping meat one day a week can have pretty substantial affects on emissions[1]. Or you can get involved with a group that is organizing around climate change.

[0] - http://www.goodcarbadcar.net/2016/01/usa-suv-crossover-marke... [1] - https://en.wikipedia.org/wiki/Livestock's_Long_Shadow