Let's pretend people formerly invested in banks and financial institutions intermingled in the Dakota Access Pipeline and any/all other fossil fuels extraction and infrastructure left and took their money somewhere else. Perhaps there was a very significant divestment in those entities and, simultaneously, investments in credit unions. How would this affect the economy? This tactic is currently being used and people are feeling empowered - I wonder how it will play out.
While the sorts of investments in fossil fuels cannot easily be reinvested in credit unions (the latter dont usually work that way) and while the size of any such redirection of investment would be important to determine its likely effects, your general idea is correct. Changing movements of capital into and out of some industries in favor of others have all sorts of effects (sdepending on the larger contexts in which they occur). I suspect that the problem around the Dakota Access situation is frustration that so many opponents of the pipeline feel given the obstacles put up by the companies and the politicians they control/buy/own. Yet I must say that the courageous oppositions of local people, allies from around the country, and by the addition of the veterans especially have been very effective as ways of empowering opposition. That is not lost on people around the country and will have many ripple effects....probably much more so than moving capital around (unless the growing fossil fuel divestment movement can become large enough to impact the industry (and that would require considerable growth from here).