Geoscience Reference
In-Depth Information
Figure 1: NASA GISS Global Land-Ocean Temperature Index plotted as annual
average temperatures on an absolute scale similar to a liquid in glass alcohol
thermometer
Source: Plot of NASA GISS global average surface temperature from 1880-2013, with thanks to James Sexton for
conversion assistance. Data derived from “GLOBAL Land-Ocean Temperature Index in 0.01 degrees Celsius base
period: 1951-1980,” National Aeronautics and Space Administration, accessed July 10, 2014,
http://data.giss.nasa.gov/
Since such plots generally don't get people all that concerned, for obvious reasons,
most depictions of the global average surface temperature are done with temperature
anomaly graphs, which magnify the change within a small range and show the change
(anomaly) from a base average temperature. They also have another advantage and that
is the choice of the baseline period, in the case of NASA GISS, considered the original
reference source for global warming claims, they use a baseline period from 1950-1980.
This just happens to be the coolest period of global temperature in the twentieth century,
thus making the deviation from the 30-year average temperature. An example is shown in
Figure 2.
