Food insecurity

Lack of adequate food is traditionally a bigger issue in developing nations. So given this reality, why would anyone make a case that this is of global concern, rather than a humanitarian concern specific to a particular (underdeveloped) region? In other words, why should someone in the United States care about the hunger and famine in places such as sub-Saharan Africa, other than humanitarian concern? Can wealthy nations safely ignore the issue and not be affected? Is climate change and a slowly growing global economy leading factors when discussing food insecurity in the United States?