Re: OT: Global Thermal Regulation
- From: Free Lunch <lunch@xxxxxxxxxxxxxx>
- Date: Sun, 04 Oct 2009 15:58:01 -0500
On Sun, 04 Oct 2009 15:47:14 -0500, heekster <heekster@xxxxxxxxxxx>
wrote in talk.origins:
There has been some back and forth in here in t.o. regarding Global
Warming. While it is apparent that human emissions can contribute to
such an effect, such an impact pales against a single 9 hour volcanic
eruption, which knocked the Earth's surface temperature down 1.3
degrees F, over a period of about 3 years.
But, as you note, the effect of volcanos goes away because of the
natural changes in the atmosphere. As long as human activity puts
notably more carbon dioxide into the atmosphere than is removed, we will
be responsible for increasing carbon dioxide levels.
The eruption of Mount Pinatubo occurred on June 15, 1991, and was one
of the largest eruptions of the twentieth century. The event lasted
about 9 hours and erupted over a cubic mile of rock material. It
injected a 20 million ton sulfur dioxide cloud into the stratosphere
to an altitude of more than 20 miles. The Pinatubo cloud was the
largest sulfur dioxide cloud ever observed in the stratosphere since
the beginning of such observations by satellites in 1978. It caused
what is believed to be the largest aerosol disturbance of the
stratosphere in the last century, although smaller than the estimated
disturbances from the eruptions of Tambora in 1815 and Krakatoa in
1883. Sulfate aerosol formed in the stratosphere from sulfur dioxide
in the Pinatubo cloud increased the reflection of radiation from the
Sun back into space. Consequently, the Earth's surface cooled in the
three years following the eruption, by as much as 1.3 degrees
(Fahrenheit). The sulfate aerosols also accelerated chemical reactions
that, together with increased stratospheric chlorine levels from
man-made chlorofluorocarbon (CFC) pollution, destroyed ozone and led
to the lowest ozone levels ever recorded to date in the stratosphere.
The above is taken from U.S. Geological Survey Open-File Report 97-262
There are around 70 active volcanoes in the US, and here is a list of
the planets volcanoes:
http://en.wikipedia.org/wiki/Lists_of_volcanoes
The 1815 eruption of Tambora in Indonesia blanketed the atmosphere
with ash; the following year, 1816, came to be known as the Year
Without a Summer, when frost and snow were reported in June and July
in both New England and Northern Europe. The sulphur cloud from the
eruption was probably significant in respect to the cooling.
The 1980 eruption of Mt. St. Helens lowered global temperatures by
0.1OC, the much smaller eruption of El Chichon in Mexico lowered
global temperatures three to five times as much. Although the Mt. St.
Helens blast emitted a greater amount of ash in the stratosphere, the
El Chichon eruption emitted a much greater volume of sulfur-rich gases
(40x more). It appears that the volume of pyroclastic debris emitted
during a blast is not the best criteria to measure its effects on the
atmosphere. The amount of sulfur-rich gases appears to be more
important. Sulfur combines with water vapor in the stratosphere to
form dense clouds of tiny sulfuric acid droplets. These droplets take
several years to settle out and they are capable to decreasing the
troposphere temperatures because they absorb solar radiation and
scatter it back to space.
Such sulphur hazes are believed to have been the primary cause of the
global cooling that occurred after the large Pinatubo (1991) and Laki
(1783-1785) and Tambora eruptions (1815).
There are numerous causes for climate cooling: decreased solar
activity, increased volcanic activity, internal variability of the
climate system, disruption of the thermohaline circulation, and
anthropogenic influences. One of the difficulties in clearly
identifying Global Warming or Cooling is the lack of consensus on what
constitutes "normal" climate, or if one exists.
Look at our climate history. Look at the climate that humans are relying
on.
There seems to be a spectrum of opinions about this, ranging from the
"ALGORE I-invented-the-internet" school of global warming, to
cautious reports of a quiescence in sunspot activity, which is an
observed harbinger of lower temperatures.
http://www.foxnews.com/story/0,2933,518958,00.html
Are you still repeating those tired old lies about Gore that the right
prattled on about? How silly of you.
As for causes, yes, there are many actions that affect the expected
temperature of the earth. Human activity is one of them. The folks who
refuse to acknowledge that human activity is affecting the climate are
the ones who need to explain why they reject scientific observations.
.
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