@Antanicus Hard disagree. The statistics here aren't useful - would you argue that we only use 30% of the Earth's area because we don't live on the oceans, so we could triple the population with no issues? We don't live on a lot of land because we farm on a lot of land.
We're already living in an unsustainable way - and adding 10 billion more people would make the move to a sustainable way much more painful than it's already going to be.
It's not a race issue - this is a problem for everyone.