Ever since humans were created, they have always been dependent on an external energy source. Before the use of fossil fuels was discovered, people used the sun as their main source of external energy. The sun provides heat, light, and photosynthesis for the food that humans and animals need to power their work. And it also influences the movement of wind and water which humans also use to produce energy to carry out heavy work. The discovery of the use of fossil fuels allowed the beginning of the industrial revolution at the beginning of the 19th century. And it has also fostered the growth of human population, technologies and wealth. Since then, man has used fossil fuels as the main source of external energy. That period could be renamed the energy revolution. But if we continuously use fossil fuels as energy, it will bring a big problem for humanity in the future. It is because the continued use of fossil fuels threatens our global energy supply and also causes many negative effects on our environment. Global energy demand is expected to double by 2050 in response to population growth and industrialization in developing countries. The supply of fossil fuels is limited by its limited quantity within the earth and will soon run out if we use it continuously. The longevity of fossil fuel energy supplies is reduced by the energy consumed through its conversion into an energy form suitable for human use. While global oil and gas reserves are concentrated in a few regions of the world, demand is growing everywhere. As a result, the world's energy supply will be difficult to secure in the future. Beyond that, the use of fossil fuels is not good and puts human health at risk. It's because... half of the article... more studies, attempts, time and money are needed to realize the use of hydrogen as a future global energy source. Works Cited Braun, Harry W. The Phoenix Project: Moving from Oil to Hydrogen. Phoenix: SPI Publications and Productions, 2000. Crabtree, George W., Mildred S. Dresselhaus, and Michelle V. Buchanan. "The hydrogen economy". Dec 2004. 12 Oct 2005 .Gorman, Jessica. “Hydrogen: the next generation.” October 12, 2002. October 12, 2005 "Hydrogen Topics." October 04, 2005. U.S. Department of Energy. October 12, 2005. Weisz, Paul B. “Basic Choices and Constraints on Long-Term Energy Supplies.” July 2004. 12 Oct 2005 .