The laughably named 'Skeptical Science' site (a climate/warming doomsday site) provides a a handy trend calculator, which confirms whether a linear temperature trend is actually 'real' - or in statistical parlance, is the trend 'statistically significant' or not, using the widely accepted 95% confidence interval test (2 sigma).

For example, by entering '**1989.58**' for August 1989 and '**2013.5**' for July 2013, the calculator determines the temperature/century trend (purple circle) and the 'uncertainty' (green circle) associated with that trend.

To be statistically significant or 'real', per the Skeptical Science experts, the trend (purple) has to be larger than the uncertainty (green). As can be seen, for the period chosen in this example, the 24 years (288 months) ending July 2013, the "global warming" trend is not statistically significant.

That means, because of the large uncertainty amount, the 'real' warming trend could actually be much smaller, even '0'.

So, in a nutshell, the pro-Alarmist site that constantly proclaims AGW-doomsday confirms that for 24 years the reported "global warming" may be a statistical fluke - not 'real'.

Note: This example uses the RSS dataset, which is the global temperature anomalies for the lower atmosphere. For a complete analysis of other temperature dataset trends, go here.