From MSN Encarta:
Sun
In just one second the Sun emits more energy than humans have used in the last 10,000 years.
Distance between sun and earth: 500 s * c or ~1.5*10(11)m
The area for this big a sphere: ~3*10(23) square meters
The area for the shade of earth: ~10(14) square meters
The energy ratio of sun emit to earth absorbed: 3*10(9)
10,000 years equal to 300 billion seconds or 3*10(11) s
This means the energy earth absorbed from sun in 10,000 years equals to that sun emited in 100 s.
Therefore, human being only uses about 1% of the energy sun gives to earth.
And part of this causes today’s global warming!