No matter anyone's feelings towards money, be it good or bad, it is a necessity. Plain and simple. There has got to be some system of exchange in any society.
If there were no money, then nobody would work in crappy jobs. We would have no food service, janitorial, or garbage collection employees, because why do those jobs when you don't need a paycheck to put food on the table?
Or even if we were to implement a system where people are assigned their given jobs, and face punishment if they fail to do them in a satisfactory manner, there will still be problems with resentment. Since there is no money, there is no difference in reward for a person who sits in a tollbooth all day and a heart surgeon. One of them didn't really have to go to school at all and has an easy, low stress job while the other spent 20+ years in school and has people's lives in their hands constantly. You don't think one deserves better compensation? Because if there isn't any, then the heart surgeon is getting screwed, and they will know it.
Humans simply aren't benevolent enough to work like that without any compensation. Sure, in your bizarre scenario of the world being on the verge of catastrophe people would likely be willing to part with large sums of money, people would be willing to work towards a solution without expecting pay, but this is a different circumstance. Here they are working towards the survival of themselves and the human race. Their motivation to do the work is survival. How will flipping burgers at McDonald's help save humanity?