The really amazing number is the rate of warming at the North Pole, which they also measure. It comes out to 0.42 ± 0.03 °C/decade since 1979. (r2 = 0.28, but it is statistically significant.) That's one degree Fahrenheit every 13 years, though these temperatures too have been basically flat for the last several years.
Here is a nice paper that explains how to calculate slope uncertainties and statistical significance: "Statistical significance of trends and trend differences in layer-average atmospheric temperature time series," B. D. Santer et al, Journal of Geophysical Research (2000) v 105 n D6 pp 7337-7356. [PDF] You can accomplish it in Excel with the LINEST function.