** **

The temperature of the surface
atmosphere over land has been rising during recent decades. But surface
temperature, or, more accurately, enthalpy which can be calculated from
temperature, is only one component of the energy content of the surface
atmosphere. The other parts include kinetic energy and latent heat. It has been
advocated in certain quarters that ignoring these additional terms somehow calls
into question global surface temperature analyses. Examination of all three of
these components of atmospheric energetics reveals a significant increase in global
surface atmospheric energy since the 1970s. Kinetic energy has decreased but by
over two orders of magnitude less than the increases in either enthalpy or latent
heat which provide approximately equal contributions to the global increases in
heat content. To put this increase in atmospheric energy into perspective, a
cylinder of air 100 m in diameter and two m high is gaining an equivalent
amount of energy as that required to raise a 1,500 kg SUV at a rate of 700
meters per decade. A 9.5 kg bicycle gaining that much gravitational potential
energy would, after 10 years, be just above the mesosphere at an elevation of
114 km. The total increase in energy of the lower two meters of the atmosphere
over land, 1.9 x 10^{17} J decade^{-1}, is large but still three
orders of magnitude less than the concurrent increase in heat content of the
top two meters of the ocean and five orders of magnitude less than the
concurrent increases in ocean heat content from 0 to 700 m depth.

Supplementary URL: