Many issues might interest you. Fossil fuels are a worry to me. Technological expectations of third world inhabitants are rising. These two factors, combined with the pollution caused by burning of these fuels are the most immediate threat to the peaceful development of humanity that exists. Sure we have several possible replacement technologies, but the change of underlying infrastructure requires a long lead time.
Solar energy is abundant and present.
Every second, the sun converts 600 million tons of hydrogen to helium, with mind boggling amounts of energy released. The sun is so big it takes thousands of years for that energy to filter out to the surface where most of it is released as light. This is a huge amount of energy in practice, quite enough for humanity's current needs, but insignificant compared to what is available in space, even in near earth orbits. Abundant energy means abundant wealth. With basic needs met on earth, and a new frontier in space, there is a chance that the earth will become a peaceful place.