Figure 1 - Monthly averaged temperatures sampled nearly globally for the lower troposphere (roughly two to eight kilometres altitude) from microwave sounder unit instruments onboard NASA satellites. The large spike of warmth resulted from the temporary natural warming of the Pacific Ocean by the 1997-1998 El Niño event.
|Figure 2 - Changes in the sun's magnetism (as evidenced by the changing length of the 22-year, or Hale Polarity Cycle, dotted line) and changes in smoothed Northern Hemisphere land temperature through 1986 (solid line) are closely correlated. The sun's shorter magnetic cycles are more intense, suggesting periods of a brighter sun, then a fainter sun during longer cycles. The record of reconstructed Northern Hemisphere land temperature substitutes for global temperature, which is unavailable back to 1700 (S. Baliunas and W. Soon, 1995, Astrophysical Journal, 450|