As the world population keeps increasing and the standard of living keeps improving, energy systems are bound to face several challenges. At present, there is a need to meet increased energy demands whilst limiting the carbon content of the energy mix to a level that will keep the global temperature rise to well below +2°C above pre-industrial level before the middle of the 21st century. Many routes have been proposed to keep this target. For the Sustainable Development Scenario (SDS), greenhouse gas emissions are expected to be brought down to zero before the end of 2080. One way is to cut down the carbon content of energy resources by at least 4% per year of its present value if the projected growth in the GDP of 2.1% per year is kept constant. Ironically, the available carbon-free energy technologies have not yet been fully developed to be competitive enough to replace fossil fuel technologies. The transition to carbon-free technologies will take a longer time to evolve. Consequently, the fossil fuel power technologies will continue to dominate the energy mix. However, many roadmaps and technological options have been proposed and adopted at global and regional levels to transform energy systems to low carbon to achieve zero emissions before the end of the 21st century. This paper reviews historical trends, assessing the gains of different climate change adaptation options and roadmap scenarios to achieve a carbon free energy system before the end of the 21st century. It also looks at the implications of the global energy transition. Finally, the paper suggests the need for a holistic approach to the global energy transition as the transition has political and socio-economic implications.