LVXXU

Climate Science
The key conclusions from climate science—as embodied in the most recent reports of the Intergovernmental
Panel on Climate Change, 63 the National Academy of Sciences (jointly with the Royal Society of London), 64
and the Third National Climate Assessment of the U.S. Global Change Research Program 65 —are that GHGs
emitted by civilization’s energy system are the dominant cause of changes in climate being observed across the
globe; that the changes not just in average conditions but in extremes are already causing harm to life, health,
property, economies, and ecosystem processes; and that deep reductions in GHG emissions will be required if
an unmanageable degree of global climate change is to be avoided.
Climate Trends
The annually and globally averaged air temperature near Earth’s surface has been directly computable from
thermometer measurements around the world since the late 19th century; determinations of this average over
the period 1880–2014 by the National Oceanic and Atmospheric Administration and the National Aeronautics
and Space Administration are shown in Figure 1-5. According to the best estimates of both organizations, 2014
was the hottest year since 1880, 2010 the second hottest, and 2005 the third hottest.
The increase in the average temperature, amounting to about 1.4 degrees Fahrenheit for the world and 1.6
degrees Fahrenheit for the United States, is not per se the essence of the climate change problem, however.
These average temperatures, like the temperature of the human body, are simply indices pointing to the overall
state of a very complex system. In the case of climate, the state of the system includes not just the averages, but
the spatial and temporal variations of temperature, humidity, clouds, winds, rainfall and snowfall, and tropical
and extratropical storminess, as well as such closely related factors as sea level; sea-ice cover; ocean currents;
the stability of permafrost; and the amount of water stored in groundwater, snowpack, and mountain glaciers.
Figure 1-5. Global Average Surface Air Temperature Relative to the 1951–1980 Average 66
Degrees Fahrenheit
1.25
1.00
0.75
0.50
0.25
0.00
-0.25
-0.50
-0.75
-1.00
-1.25
1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010
NOAA
NASA
QER Report: Energy Transmission, Storage, and Distribution Infrastructure | April 2015 1-11