Because for some reason I can't decide which is more right? There are some people who say it's not a big deal and that without humans using resources, the world would end up in an ecological disaster. Is that true? I don't see how that is given we need more resources than other species and we are more likely to cause overconsumption. So which is more true?

There is debate about this although I am not sure if it is always useful. Humans are quite destructive and there is no doubt we are causing a lot of problems for ourselves, and for other organisms on the planet. So simplistically, if we want less cumulative damage - the two positions we could argue for are reducing the number of people in total or reducing the impact of each person. People who think the first is the solution argue overpopulation is the problem, people who think the second argue it is overconsumption!  I think the split tends to reflect political/philosophical/ethical ideology rather than actual biology.

This may be of interest

[size= 12px]http://www.theguardian.com/sustainable- … ainability[/size]