1. "The global average surface temperature has increased over the 20th century by about 0.6°C."
Not "may have", or even "is likely to have', but simply "has". FALSE CERTAINTY. Any suggestion of doubt is omitted, but there is plenty to doubt.
2. The text itself says "The global average surface temperature (the average of near surface air temperature over land, and sea surface temperature) has increased since 1861. Over the 20th century the increase has been 0.6 ±0.2°C (Figure 1a). This value is about 0.15°C larger than that estimated by the SAR for the period up to 1994, owing to the relatively high temperatures of the additional years (1995 to 2000) and improved methods of processing the data. These numbers take into account various adjustments, including urban heat island effects."
This is the only reference in the text to any possible problems with the temperature record. It says they have been "taken into account", with special reference to the urban heat island effect. FALSE CERTAINTY. The discussion of these problems, how likely they are to be significant, and how they have been taken into account, has simply been omitted. In fact how well they have been taken into account is highly contentious.
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I'll admit that I'm not smart enough to figure out how the IPCC came to that number; an increase of 0.6C over the 20th century.
This doesnt make sense to me at all, what are they comparing 1908 to 2008? Or do they take the average of each 100 years and then add them up divide by years? HOW do they get that number ? Anyone?