I see that religious belief seems to be growing (according to this study, at least; I've seen others that say the opposite); but I'm curious about your comment regarding the "necessity of religion." That's what I wanted you to explain. Nothing in that graph, or that article, tells me why religion is necessary for human existence, nor why "religion = procreation" and irreligious tendencies or atheism does not.
You have graphs. You don't have an argument.
It isn't that religious belief is growing necessarily, in the sense of conversions (evangelicalism is a generally Christian idea anyway). These projections can be derived from fertility rates. Fertility rates are low and dropping across the globe (a quick google will confirm this). However, exceptions remain in two places, in general: Extremely poor places and amongst religious groups which prioritize reproduction.
On the other hand, where data is available, atheism is removing itself fairly quickly from the gene pool in comparison. Increasing living standards also generally correlates with reduction of fertility rates to replacement or subreplacement levels, but not
necessarily, as strong religious subcultures have shown (Muslim, Amish, Orthodox Jews, etc.) The fertility rates in the US isn't dire quite yet, but it seems this is due to Muslims and mestizos - much more religious subgroups, than the WASP/C majority, soon to be minority.
Unless the goal is the death of genes and of ideas, it appears that enlightened atheistic western liberalism is quite the ultimate failure. Of course, it isn't a clear tenet of liberalism or atheism to not procreate, but if these are the comparative effects, it cannot be ignored.