Discuss what you believe will be the defining issue of international relations in the 21st century. Some possibilities to consider are the environment, human rights, potential great power war, the rich/poor divide, etc. Use reputable publications for your research beyond the textbook such as those produced by the UN and its affiliates (i.e. The World Development Index, UNEP publications, etc.), academic journals, or other national or international organizations. Be sure to include what is being done on your issue, international relations theories relating to it, and potential ramifications.