Actually it's not. As all of the problems he cites have occurred under capitalism.
There is enough food, clothes, housing, medicines etc to support a reasonable standard of living for the population of the planet. I thought every socialist understood that. Nowhere has Francis given a population figure he thinks is sustainable. I can assure you that nobody wins here. As long as we have capitalism, you, Francis and even I are the losers. Because what would he won if can prove that socialism won't work?