Tuesday, June 24, 2008

Hansen on global warming: 'This is the last chance"

Within a discussion about global warming, one has the text:

that the world has long passed the "dangerous level" for greenhouse gases in the atmosphere and needs to get back to 1988 levels.

IPBiz notes that, while the term "greenhouse gas" is ever-present in the environmental discussion, it is a misnomer. More than thirty years ago, this misnaming was pointed out in the journal Science:

From The "Greenhouse Effect",
Robert G. Fleagle and Joost A. Businger,
190 Science 1042 (1975):

[G]reenhouses are warmer than
the surrounding air because the glass pre-
vents the warm air inside from rising and
removing heat from the greenhouse. Ab-
sorption of infrared radiation by the glass
contributes only a little to the warming ef-
fect. Polyethylene sheets, even though they
are largely transparent to infrared radi-
ation, are just about as effective as glass in
greenhouses The essential facts were es-
tablished by a simple experiment carried
out by Johns Hopkins University physicist
Robert W. Wood in 1909. He found that
two model greenhouses, one covered with
glass and the other with rock salt (which is
transparent to both short- and long-wave
radiation) reached very nearly the same
high temperatures. Thus the "greenhouse
effect" results from suppression of vertical
convection by a rigid lid.

The earlier paper in question is
Robert W. Wood,
Philosophical magazine , 1909, vol 17, pp. 319-320.

One would hope after one hundred years, scientists
would get the "greenhouse" issue right.


Post a Comment

<< Home