A Carbon tax would only correct a minor part of the greater species problem. It alone would not assure human survival. At the core of the issue are those external costs not being recognized in pricing. Given the assumption that capital markets are here to stay in one form or the other, the statement can be made as seen in my letter to Paul Krugman (see http://www.InquiryAbraham.com Blog Tab) that in order for human ecological survival, all external costs need to be measured and priced in up front so as to encourage, discourage, temper, or at the extreme eliminate investment. Also, we must understand; implicit in this assumption is that only government can be in a position to recognize these negative external costs. To the extent that the economics profession has not been an influence on government in this regard, it has now become a large part of the problem.