How many earths do we need at current global rate of consumption?

I have heard this figure before but forgot what the specific number is. I would love a source so I can share it.

I want to know how many earths are needed at the current rate of global natural resource consumption. I thought it was 2.5 or something.

I found this BBC article that shows how many earths would be needed if everyone lived like an American, but I want to know the current global rate of consumption, and how how many earths would be needed to maintain it.

Here's the BBC article: http://www.bbc.com/news/magazine-33133712

From what I remember and from what I could find it looks like we are at about 1.5 or 1.6 Earths at current consumption levels. Of course this can be difficult to fully measure but this seems to be the current best estimate. Here is a link to a site talking about it: http://www.footprintnetwork.org/our-work/ecological-footprint/#worldfootprint