I think fiscal conservatism is pretty essential to any real environmentalist. Environmentalism -- at least the kind that is concerned about larger matters than saving scenic overlooks -- is all about efficiency and sustainability. I don't think you can call yourself an environmentalist if you aren't frugal. And those same values connect well with a lot of progressive economic values. When I think about economic empowerment in a wealthy society like ours, it's not that people don't have enough. My concern is how people are manipulated and trapped by the economics of our environment, not how they are deprived. Which is a concern about "social welfare", insofar as it's a concern about the welfare of the populace... but it's not something that is solved by resources.
For instance, I don't think failures of the Great Society programs of the 60s and 70s were because they didn't have enough resources. It was because bureaucrats at a variety of levels took those programs and made sure they didn't work. Because public housing turned into a means of seggregation. Because AFDC turned into a way to keep people in an economic holding pattern. In the face of potential reform, resources are often offered as a way to coopt the reform rather than enable it.
This becomes more important in this race, since this is a race between a Green Party candidate and a Democratic candidate. There's a Republican candidate, but he'll never gets past the primary; Republicans seldom even bother to run in Minneapolis. There's no liberal/conservative dichotomy between the candidates. The distinction is about governance, not rhetoric. The two parties, and the two candidates, are better distinguished as the institutional party (the Democrats) and the reform party (the Greens). The Green party -- and I think my father particularly -- understand how resources and institutionalization are enemies of real reform.
Plus, you should see the car he drives. He's clearly walking the walk when it comes to fiscal conservatism on the home front.