If our descendants are to have a life worth living in the twenty-first century, humanity must address and solve three critical issues which have global significance. Regardless of their novelty, these issues are so pivotal that they will determine the future of our descendants. These critical issues that must be solved are the problems concerning environment, the population, and the gap between rich and poor. If humanity truly wants to address these issues, it has to understand the current situation and must find reasonable ways to act upon them.

Human influences on the natural world are both more noticeable and more prevalent than any other time in history. Around the globe, signs of environmental degradation can be found everywhere. For instance, past productive pasturelands are turning into deserts at a shocking rate while low-lying coastal areas seem to be threatened by flooding from rising sea levels. The air...