Is there still a role for the state?

I am sometimes asked why we need to use the state to make the political changes that are needed in order to address the climate crisis; in order, for example, to make Transition Towns have the real-world impact that they deserve to have.
The answer is straightforward: The state has to provide the caps that make a framework within which public goods (such as limits to pollution so that we stay within our ecological limits) are incentivised and public bads are disincentivised. The only fair way to do this is through carbon entitlements, etc. [See e.g. http://www.feasta.org/documents/energy/dtqsoct2003.htm ] That is why it is Green Party policy to introduce such a scheme. Without such a scheme, either one introduces regressive carbon taxes (which is what, inasmuch as their policies address the issue at all seriously the Conservative Party and the LibDem Party propose to do, in effect punishing the poor for the emissions of the rich); or one simply gives up the ambition to be serious about carbon-reduction nationwide, and so about Contraction and Convergence etc. worldwide.
As I have argued in several posts during the last week, there is no voluntary-based way of reducing fossil fuel use, ESPECIALLY once one reaches the limits to growth, and less for one person simply opens up the opportunity of more for another. The climate crisis and Peak Oil introduce a renewed and utterly vital role for the state: setting the framework which gives us some chance of acheiving climatic balance again, by creating the conditions under which low-carbon living can happen for all.
Opposition to the positive use of state power is nothing less than a total disaster, an abnegation of responsibility, in the historical period that we are now in.
And recall: it is unbridled corporate power -- it is the unleashing of capital that has been the big economic-political story of the last 25 years or so -- which has got us into this emergency in the first place...