Geoscience Reference
In-Depth Information
The preparation of chicken, pork, and beef
produces more greenhouse gases than the
transportation or industrial or residential
sector. Of the 36 billion tons of CO
2
and
other greenhouse gases released annu-
ally, 18%, or 6.5 billion tons, is from meat
production. Beef production is the largest
villain and it works like this: 40% of the
emissions are from reduced CO
2
absorp-
tion caused by the loss of the plants that
cattle eat; 32% is from the gases that cattle
emit and the emissions from their waste;
14% is from fertilizer production; and 14%
is from general farm activities. Accord-
ing to an article in
Scientific American
by
Nathan Fiala, the emissions attributable to
the meat in a hamburger from Burger King
are equivalent to the emissions from driv-
ing a small car for ten miles. Consider that
in addition, modern meat production typi-
cally involves transporting the product far
from the slaughterhouse, and that Whop-
per you consumed for lunch is increasing
more than just your waistline.
of Luzon in the Philippines, can tempo-
rarily inject huge amounts of aerosols into
the atmosphere. Human beings contribute
black carbon aerosols through slash-and-
burn deforestation, and they produce soot,
sulfates, and nitrates in the form of smog
from air pollution and dust created by agri-
culture, desertification, and other activities
and events on land. Some aerosols have a
regional cooling effect, as they reflect solar
radiation back into space. And cooling from
a major volcanic eruption will usually last a
year or two. Industrial effluents also include
such aerosols, some of which cause cooling
(sulfates) while others cause warming (soot).
Some aerosols are also responsible for
cloud formation, and the amount of aero-
sols in the atmosphere determines the
type of cloud. High concentrations result
in bright, white clouds, which are very ef-
fective in reflecting sunlight (thereby cool-
ing the Earth). Darker clouds, which form
when aerosols are less concentrated, will al-
low more of the sun's energy to reach and
warm the Earth.
Satellite observations have shown that
the paths of ships in the open ocean can
sometimes be seen as spectacular, long,
thin lines of clouds, produced as the sulfur
dioxide from smokestacks is emitted in the
form of sulfate aerosol particles which lead
to cloud formation. This is a clear indica-
tion of the importance of fossil fuel burn-
ing in forming aerosols.
The overall impact of aerosols is to cool
the Earth, more in the northern hemi-
The role of Aerosols
Aerosols are tiny particles or droplets sus-
pended in the atmosphere. Much remains
to be learned about them, but it seems that
most atmospheric aerosols are purely natu-
ral, derived from natural processes such
as oceanic salt spray, forest fires, and dust
storms. Volcanic eruptions, such as the
eruption in 1991 of Pinatubo on the island
