I presented this at the Kay County
Republican meeting, concerning climate change.
There are two parts, History and Science. My expertise is not large but I can explain
the issue. When at KSU in the 70’s I was
tapped to be temporary Librarian for the Weather Data Library-- oldest
continuous weather records in the United.
Years later I ran a hotel and some of the top climate change scientists
in the world frequented our area. Due to
some odd circumstances, word spread that a former colleague (not quite true!)
ran a nice hotel. We got lots of
reservations and became something of a headquarters for the scientists who
descended on Ponca City’s airport and Lamont’s climate station. Result was a lot of evening discussions in
the lobby. One night Dr. Tim Tooman, Scripps
Oceanographic Institute, author of the El Nino theory gave me a renditon of
“the big picture” of the whole climate change controversy which will be in the
Science section. But first the History.
The largest climate changes are the ice ages that
may have begun almost 3 million years ago.
Earth became 30-40 degrees cooler and glaciation covered half of the
northern continents. Oh, by the way, I
don’t want to offend anyone’s faith. If
you believe in a 6000 year earth, just realize that if we make a road cut,
there are artifacts that bespeak many years of a former history. Now whether God just put this in the rocks as
a virtual history or whether it is real—you decide. And we can still talk in apparent years.
Ice ages were 40-60,000 years long
and had interludes of typically 140,000 years between when the climate was considerably
warmer than today. What caused them? We
think the nutation of the earth (these wobbles occur every 17,000 years) could
have been coupled with continental drift that made the poles landlocked is the
reason. Landlocking the Arctic Sea and
the Antarctic continent means that poles can grow an ice cap. Then either a
solar radiation change or nutation threw the planet into increasing glaciation
as the polar caps reflected more and more sunlight back into space and drove
temps down. But the jury is still out on some of this theory. The last ice age ended roughly 20,000 years
ago and the earth began to warm.
About 11,700 years ago the
Younger-Dryas era occurred where the warming reversed and became markedly
colder. Many large animals such as
mastodons and sloths died during this era, like the ones you have seen as
cartoons in the Ice Age movie. (Younger-Dryas when the Scrat froze just
inches from the tantalizing acorn?) Younger-Dryas was also an era when we believe
that Caucasians in N. America were either were killed or absorbed by Mongloid
people from Eastern Siberia who became the Indians. What caused this cold, dry era which lasted
1700 years? One theory is that glacial melt
which originally went down the Mississippi valley was captured by the St.
Lawrence Valley and suddenly went north changing the ocean current patterns and
causing a very cold era until more warming took over as the polar caps shrank.
So was this just a N. American effect?
It seems to have occurred in the Southern hemisphere too, but at not
exactly the same time. There’s about a
thousand years of overlap.
Then about 6000 years ago, the
Sahara began to warm and dry up very slowly.
Shortgrass savanna, somewhat like the OK panhandle, turned into a desert
like New Mexico. It drove the hunters
and gatherers off the Sahara and into the Nile river valley where they
developed agriculture. Cause of this
warming is unknown. Then another warming
which was much more cataclysmic and faster occurred about 4200 years ago. We think one or more dust bowl warming events
happened. It dryied the Nile so much
that the river refused to flood. But the
people of the Nile, at this time weren’t irrigating, just using the annual
floods to wet the land. So a 30-yr. Dust Bowl and no floods caused famines. The sudden disappearance of the Old Kingdom
of Egypt and the similar fate of the Akkadian civilization in Asia
Minor-Arabia, and several other places in the East all happened at this precise
time. The Sahara went from New Mexico
vegetation to sand dunes as it is today.
Cause has been explained as change in ocean currents off Africa but this
doesn’t explain Arabia.
In more modern times, the era from
800 AD to 1300AD was a particularly warm one called the Medieval Warming. This
time we have a measurement of the temperature difference. It became about 5 degrees warmer than in
Roman times. Wine grapes were grown in England.
It’s too cold to do that today.
Vikings traveled to Iceland and deforested the island, then Greenland
and settled there during better conditions than exist today. This warm era allowed better crop production
and led Europe out of the Dark Ages.
Cause however is not well established.
From 1309 to 1850 a disastrous era
called the Little Ice Age took over. We
know the dates and cause fairly exactly because Chinese monks who studied the
sun with lampblacked glass (part of their religion) suddenly recorded that
sunspots almost disappeared in 1309. The
scarcity of sunspots continued until 1850.
Climate was about 7-10 degrees cooler and the cold has an obvious cause.
Sunspots are storms on the solar
surface. When they are plentiful it
means that the sun is having more radiation output. So solar radiation went down during the
Little Ice Age. Dickens wrote Christmas Carol with snow on the streets
of London. That is a truly rare occurrence
nowadays. Was this climate change worldwide?
The jury is still out somewhat on this point.
Another climate change was the Dust
Bowl which affected N. America only.
From 1931-1938 midcontinent temperatures averaged 10 degrees warmer, and
rainfall dropped by half, then returned to normal. What cause?
Not well understood but one theory is a prolonged La Nina cycle.
Bottom line of all these events is
that climate changes quite a bit and it is natural. Fred Flintstone didn’t pollute the atmosphere
with too much gasoline in his rock car!
There wasn’t enough fossil fuels being burned in any of these eras to
cause changes.
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