http://www.cru.uea.ac.uk/cru/data/temperature/hadcrut3gl.txt
YEARLY AVERAGE GLOBAL TEMPERATURES IN DEGREE C RELATIVE TO THE AVERAGE FOR THE 1961-1990 BASE PERIOD
1909 -0.564
1961 -0.023
1990 +0.254
1998 +0.546
2007 +0.421
In 1909, global temperature was 0.564C
below the average temperature for the 1961-1990 base period. In 1998,global temperature was 0.546C
above the average temperature for the 1961-1990 base period. In 2007, average global temperature is 0.421C above the average temperature for the 1961-1990 base period.
In aviation, the global standard temperature is 15C (59F). Assuming the average temperature during the 1961-1990 base period is the same, then the actual temperatures centigrade:
1909 -0.564 + 15 = 14.436
1961 -0.023 + 15 = 14.977
1990 +0.254 + 15 = 15.254
1998 +0.546 + 15 = 15.546
2007 +0.421 + 15 = 15.421
From 1909 to 1998 the global temperature increased (15.546-14.436)= 1.11C (1.998F). Relative to standard temperature that constitutes a 100% x (1.11C / 15C) = 7.40% increase. Relative to the 1909 average temperature that constitutes a 100% x (1.11C / 14.436C) = 7.69% increase. Relative to the 1990 average temperature that constitutes a 100% x (1.11C / 15.254C) = 7.30% increase.
SOLAR ACTIVITY
Solar activity has increased 57% from 1900 to 2000. Solar sunspots have increased by a factor of 2.29 over the same time period.
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http://upload.wikimedia.org/wikipedia/commons/6/60/Solar_Activity_Proxies.png
Solar activity
Sunspots
Graph showing proxies of solar activity, including changes in sunspot number and cosmogenic isotope production.
Sunspots are relatively dark areas on the surface of the Sun where intense magnetic activity inhibits convection and so cools the surface. The number of sunspots correlates with the intensity of solar radiation. The variation is small (of the order of 1 W/m² or 0.1% of the total) and was only established once satellite measurements of solar variation became available in the 1980s. Based on work by Abbot, Foukal et al. (1977) realised that higher values of radiation are associated with more sunspots. Nimbus 7 (launched October 25, 1978) and the Solar Maximum Mission (launched February 14, 1980) detected that because the areas surrounding sunspots are brighter, the overall effect is that more sunspots means a brighter sun.
There had been some suggestion that variations in the solar diameter might cause variations in output. But recent work, mostly from the Michelson Doppler Imager instrument on SOHO, shows these changes to be small, about 0.001% (Dziembowski et al., 2001).
Various studies have been made using sunspot number (for which records extend over hundreds of years) as a proxy for solar output (for which good records only extend for a few decades). Also, ground instruments have been calibrated by comparison with high-altitude and orbital instruments. Researchers have combined present readings and factors to adjust historical data. Other proxy data - such as the abundance of cosmogenic isotopes - have been used to infer solar magnetic activity and thus likely brightness.
Sunspot activity has been measured using the Wolf number for about 300 years. This index (also known as the Zürich number) uses both the number of sunspots and the number of groups of sunspots to compensate for variations in measurement. A 2003 study by Ilya Usoskin of the University of Oulu, Finland found that sunspots had been more frequent since the 1940s than in the previous 1150 years.[10]
Reconstruction of solar activity over 11,400 years. Period of equally high activity over 8,000 years ago marked. Present period is on left. Values since 1900 not shown.
Sunspot numbers over the past 11,400 years have been reconstructed using dendrochronologically dated radiocarbon concentrations.
The level of solar activity during the past 70 years is exceptional - the last period of similar magnitude occurred over 8,000 years ago. The Sun was at a similarly high level of magnetic activity for only ~10% of the past 11,400 years, and almost all of the earlier high-activity periods were shorter than the present episode.