An action that the people can take is to get our governments to increase our military forces fighting ISIS. I believe this is an answer to this problem because ISIS won't be able to fight all the soldiers that are coming in, and what we are doing right now, apparently isn't enough. We should also ban pro-ISIS statements from social media, because that is the main way they get people to support ISIS.
I believe that is a good solution to defeat ISIS because we are stopping their main source of how they are accquiring terrorists and sending in more forces they can