Figure 1~13. World annual energy production by source, 1973 - 1995. Data are from the U.S. Dept. of Energy 1996 Annual Energy Review. "Renewable" energy production in this figure includes geothermal, wood, waste, wind, photovoltaic, and solar thermal (but not hydroelectric) energy production.
The total global energy use in 1995 was 383 EJ. For comparison, about 5.5 million EJ of sunlight strikes the upper atmosphere of the Earth each year, and about 250,000 EJ of that makes it to Earth's surface. So humans used the equivalent of less than 0.2% of the Sun's energy striking the Earth's surface in 1995. (That number doesn't take into account energy uses that aren't included in the U.S. DOE's figures, such as sunbathing and solar heating of homes, swimming pools, and other structures.)
Energy-wise, then, people use only a tiny fraction of the solar energy available at the Earth's surface each year. If we used only renewable energy resources, there would probably be no cause for concern. However, most of the energy we used in 1995 came from non-renewable energy resources, in particular the fossil fuels.
Global Distribution of Energy Use by Nation
Figure 2~13. World annual energy production by source, 1973 - 1995. Data are from the U.S. Dept. of Energy 1996 Annual Energy Review. "Renewable" energy production in this figure includes geothermal, wood, waste, wind, photovoltaic, and solar thermal (but not hydroelectric) energy production.