Summary
- Radiative forcing of the sun drives the earth's climate.
- Changes in the composition of the earth's atmosphere due to
anthropogenic causes are creating changes in global radiative forcing
that exceed natural variations .
- Changes in the composition of the earth's atmosphere are leading to
a redistribution of energy within the atmosphere/ocean system.
- Unless major changes occur in our pattern of energy use, C02 in the
earth's atmosphere will reach twice the pre-industrial level by the
middle of the next century.
- Global average temperatures have risen about 0.5 degrees C in the last
100 years.
- Climate models project an increase in global average temperatures of
1.5-4.0 degrees C for a doubling of C02.
- A warming of 2-3 degrees C from present levels would make the
planet warmer than it has been in the last 160,000 years, with unknown
consequences to the biosphere.