Is NOAA Misleading the Public by Including Tropical Cyclones in its 2012 Climate Extremes Index Ranking?

IF NOT, THE PRESS AND PUBLIC WILL CERTAINLY GET THE WRONG IDEA

The Summary Information of the NOAA State of the Climate report reads with respect to extremes:

The U.S. Climate Extremes Index indicated that 2012 was the second most extreme year on record for the nation. The index, which evaluates extremes in temperature and precipitation, as well as landfalling tropical cyclones, was nearly twice the average value and second only to 1998. To date, 2012 has seen 11 disasters that have reached the $1 billion threshold in losses, to include Sandy, Isaac, and tornado outbreaks experienced in the Great Plains, Texas and Southeast/Ohio Valley.

This gives the reader the impression that landfalling tropical cyclones were a contributor to the high ranking. They were not. NOAA fails to note in the summary that the landfalling tropical cyclones were so low that NOAA lowered the ranking on its Climate Extremes Index by including them. That is, without landfalling tropical cyclones, 2012 would have ranked number one on Climate Extremes Index.

Using the drop-down menu on the NOAA Climate Extremes Index graph webpage, we can plot NOAA climate Extremes indicator graphs. Figure 1 is the NOAA Climate Extremes Index graph for landfalling tropical “systems”. 2012 was extremely low, far below average. I included this data through November in my Video: Drought, Hurricanes and Heat Waves – 2012 in Perspective. I was therefore surprised when NOAA included tropical cyclones in their 2012 State of the Climate summary.

Figure 1

If we plot the NOAA Climate Extremes Index for 2012 with landfalling tropical cyclones, Figure 2, 2012 does in fact rank number 2 behind 1998. This confirms NOAA’s statement in their summary.

Figure 2

But if we exclude landfalling tropical cyclones from the Climate Extremes Index, Figure 3, 2012 rises to a ranking of number 1.

Figure 3

Therefore, by including landfalling tropical cyclones in the Climate Extremes Index for 2012, NOAA lowered the ranking, but gives the public the impression that landfalling tropical cyclones contributed to the high ranking—when, in reality, tropical cyclones lowered the 2012 ranking.