Global Warming:
Man or Nature?
G
BY KEITH STARNER, NCRWA SOURCE WATER DIVISION LEADER,
NC Licensed Geologist #1088
18
NCRWA.COM |
Summer 2013
feature
lobal warming
is a hot topic in the
news, no pun intended.
I hear about it almost every
day. When it snows, it’s Global
Warming. When it’s hot, it’s Climate
Change. But is it real? When I was in
high school, (The 70’s), I remember a
Time
magazine cover that featured “The Coming Ice
Age.” It’s enough to confuse anyone, given that one
week, scientists find that coffee is good for you and the next week it
contributes to heart attacks.
Global warming alarmists will tell you that the consensus of scientists
is that Global Warming is real, and more importantly, it is caused by
human activity. The scientific method involves recording data, and then
drawing conclusions, not achieving a “consensus.”A majority of the
scientists on the United Nations Intergovernmental Panel on Climate
Change (IPCC) committee are not climatologists, paleo-climatologists
or even meteorologists. However, there are a lot of humanities,
liberal arts, and social scientists represented on the committee. What
do sociologists know about Global Warming? Your guess is as good
as mine.
Keep in mind that accurate records of Earth’s temperature have been
kept for only the past two centuries. This is a very, very thin slice of the
geologic record. Geology studies the deposition of sediments and the
formation of sedimentary rocks, and this record extends back almost
4.3 billion years. What does this record have to show us?
Many water systems east of I-95 use the confined aquifers in the Coastal
Plain as their source of drinking water. Each of these aquifers (and their
confining clay layers) represents a cycle of ocean transgression (ocean
high stand) and regression (ocean low stand). The famous Black Creek
aquifer extends from the area near Wilson, NC, to beyond the Outer
Banks, and is of Cretaceous age (64 million years before present).
The sediments of the Black Creek were deposited over the course of
millions of years and record a cycle of the rise and fall of sea level.
There are also older aquifers (the Cape Fear) and younger aquifers,
(Castle Hayne limestone, Yorktown, and others). These aquifers all
represent and record the cyclic ebb and flow of the ocean with geologic
time, and all these Coastal Plain sediments were deposited in a
marine environment.
A quick look at the geologic map of North Carolina shows an area
called the Sand Hills. These are indeed sandy hills that were once dunes
and beach deposits. Beachfront property as far west as Pinehurst, which
is well over 90 miles inland, was a fact 64-million years ago. The Sand
Hills exhibit cross-bedding, typical of beach deposits, and have the
same composition and grain size as present-day beach sands. There are
also a number of ancient beach scarps that are well inland, and these
record the slow cyclic transgression and regression of the ocean.
Another look at any state map shows the Albemarle and Pamlico
Sounds. These Sounds look for all the world like river systems that
have been flooded. The Tar and Roanoke Rivers abruptly get very wide,
and then we stop calling them rivers and begin calling them Sounds.
The Albemarle and Pamlico look like flooded rivers, because that is
exactly what they are. Sea level is rising, folks, and the earth is getting
warmer. But is humankind responsible?
Geologists can show conclusively that sea level has risen and fallen
many, many times in the past. There is a direct correlation with sea
levels and the earth temperatures. Sea levels rise when the earth’s
temperature is hotter, and fall when temperatures are colder. So…. Earth
temperatures have risen and fallen many times, and these changes are
recorded in the sedimentary rock record. The fossil record also shows
the extinction of many species which may have been killed off during
temperature extremes or other earth calamities.
The last ice age began about 1 million years ago, and ended less
than 10,000 years ago. There have been multiple ice ages in earth’s
history, with many changes in the high and low stand of the ocean.
A fellow named Milankovitch developed a theory that may explain
the ice age-interglacial periods in earth history. Milankovich theory
states that the earth has an eccentric orbit, or precession wobble, that
affects earth temperature as it gets closer to and further from the sun.
The oscillation maxima occur about every 10,000 years and coincide
nicely with several ice age periods. Cycles of 23,000 and 100,000
years were also discovered.
