RE: warming

["A Karam" <paksbi@rit.edu>]

Regarding global warming, there are a few issues to consider:



The sun is a moderately variable star.  In addition to the 11 year

sunspot cycles, there are longer variability cycles going up to millions

of years in length.  Solar activity is one of the factors controlling

C-14 formation in the atmosphere, so we can develop solar activity

records by looking at C-14 levels in objects of known age (e.g. tree

rings) and seeing if there is more or less than we'd expect.  My

recollection is that solar activity has been on the upswing for the past

few centuries.



What we consider "global warming" is actually more of a return to the

norm.  For most of Earth's history there have been no polar ice caps.

We are currently in an unusually cold period.  Part of this may be due

to having continents clustered near the north pole - it's easier to have

snow and ice accumulation on land, and the increased albedo helps lower

temperatures.



The ice age we are currently waxes and wanes irregularly.  Humanity has

developed all of our written history and civilization during an

unusually long warm period of this ice age.  We have had the opportunity

to influence the climate for only the past half century, so we are

almost certainly not to blame for the long interglacial period we've

enjoyed.  Based on climate records, it's not certain if the climate

would normally be starting to swing back towards another glacial period

at this time.  Accordingly, we don't know if our actions are delaying

this return to colder temperatures or not.



We also know from a number of geologic and marine records that the

earth's climate is not inherently stable and that it has changed

dramatically in just a few decades.  It is also entirely possible that

the Antarctic ice sheets come and go in a geologically rapid time frame

- there seems good evidence that the current ice sheet is only a few

million years old, and possibly much younger.  This means that a small

input may have a disproportionately large effect on the climate,

depending on the feedback mechanisms.



While CO2 is a known greenhouse gas, it is not yet certain that the

accumulation of CO2 in the atmosphere is the ONLY cause for the rising

temperatures and sea levels we have seen.  It is almost certainly A

cause, but there may be others, including those noted above.  Therefore,

it's not certain whether or not limiting CO2 emissions will eliminate

global warming, reverse it, or have little effect at all.



Personally, I think this is the climatological equivalent of LNT.  The

data are not definitive and the error bars are larger than the effects

we're looking for.  This makes the question as much philosophical as

scientific at this point.  So we make our best guess while working to

refine our fundamental understanding of the problem.



Andy



P. Andrew Karam, Ph.D., CHP

Research Assistant Professor

Rochester Institute of Technology

Department of Biological Sciences

85 Lomb Memorial Drive

Rochester, NY  14623

+1 585-475-6432

karam@mail.rit.edu



A foolish consistency is the hobgoblin of little minds, adored by little

statesmen and philosophers and divines. -Ralph Waldo Emerson, writer and

philosopher (1803-1882)

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