Comments from Anthony Watts of WattsUpWithThat.com in rebuttal to James Hansen's NASA animation:

Anthony comments on the  NASA animation by Dr. James Hansen of surface temperature trends from 1955-1999:    

There are many issues with this presentation. It seems to be a big Cherry Picking exercise.

1. Note all of the missing southern hemisphere data.  There are operating weather stations during his time, but they are excluded from the analysis. Why?

2. The period chosen, 1955-1999 leaves out the warmer 1930′s and the cooler 2000′s. Why?

3. The period from 2000-present has no statistically significant warming. Leaving that period out biases the presentation.

4. The period chosen exhibits significant postwar growth, urbanization is not considered.

5. As for severe weather, Hansen ignores the fact that neither tornadoes nor hurricanes have shown any increase recently. Only smaller tornadoes show an increase, due to reporting bias thanks to easily affordable and accessible technology.  NOAA’s SPC  reports that July 2012 seems to be at a record low for tornadoes.

6. My latest results in Watts et al 2012 suggest surface station data may be biased warmer over the last 30 years.