This would lead you to believe that gun men are playing a vital role by culling the population....lol. I do think however that modern medicine, as good as it is, it will be our undoing. In the lower animal kingdoms, diseases and all sort of selective pressures along with predation keep populations in check. We humans don't have predators so we need diseases to really keep our population in check. We decrease this rate by making people who would normally die...live longer and these persons might even reproduce. While its good for the gene pool, its bad for the population. We continue to grow and consume resources until there is not enough left and then we will have mass mortalities... just like locusts after a feast.
If we had like 2 billion people in the world instead of 7...then we'd be better off. In the 1950s the world population was 2 billion. That means it took couple thousand years for the earth to reach 2 billion. Now with more people being exposed to each other... closer proximity brings about greater contact between people which leads to an increase in reproduction. This means that in the first 10s of thousands of years, the population was 2 billion and just 50 years later... we've more than tripled that number. All this combined spells disaster but then again... how many of us are willing to give up our lives for the sake of mankind? We'll all die out eventually and bacteria/fungi and cockroaches will inherit the world.