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Hemispheric Differences
Southern Hemisphere
- 8˚K Degrees peak to peak variability
- 276˚K mean
Northern Hemisphere
- 24˚K Degrees peak to peak variability
- 280˚K Mean
Equatorial
- Small 6 month periodic variability
- Clearly illustrates 2001/2002 calibration error
Notes:
The 24˚K seasonal variability in average Northern hemisphere temperatures is about double the difference seen in the average global temperature between ice ages and interglacial periods. This is due only to the Earth's tilted axis.
The Southern hemisphere variability is only 8˚K and yet results from the same tilt. This dramatic asymmetry between north and south is why effects that would otherwise cancel in a symmetric system have such a large influence on the global average temperature.
As the Earth's tilt and seasonal relationship to perihelion changes, these differences can become much larger and biased in one direction or the other.