[Coral-List] Expert Disagreement in Climate, Science
dennis.hubbard at oberlin.edu
Wed Jan 4 15:51:32 EST 2017
Gene makes some valid observations about what we know vs what we infer, and
the general confusion that arises from terminology. While I am not an
expert on much of this, I would like to offer some perspective on two of
Gene's points (a lack of knowledge has never stood in my way - and I'm
happy to observe that I'm in good company).
Regarding "global warming" vs "climate change", part of the intent was to,
in fact, show that "up" was not an inviolate thermal trend. We know that
patterns in the tropics can be decidedly different by region or latitude.
But, more important, the problem is not just a warming planet, but a world
in which climate is increasingly variable. Things like ENSO contribute to
the variability in an overall warming trend. Synoptic satellite
measurements are now showing that sea-level rise is not evenly distributed
(even if we take away local tectonic motion). Sea level is rising in much
of the western Indo-Pacific region and on the GBR at over 10 mm/yr,
compared to less than 2 mm/yr along much of the eastern US coast. This has
been explained as a response to larger-scale atmospheric forcings (again,
Because sea level cannot continuously rise more at point A than at point B
(lest we build a slope down which one can water ski), these patterns must
change over time, evening out to the global average (presently at ca. 3.5
mm/yr). This suggests that even things like ENSO, similar cycles in other
oceans and even the "ocean conveyor belt" must change temporally; some
evidence suggests a temporal scale of 30-60 years.
So, "Climate Change" is probably a more correct descriptor than "Global
Warming". My suggestion is that we try to educate the public better rather
than opting for lowering scientific rigor to the level of the average
American voter (remembering that we are the only nation to not adopt the
Regarding models, I agree with Gene's suggestion that we might not fully
know whether they accurately replicate nature. However, we can still
consider several factors that can at least approximate the level of
correspondence. First, the models start with measured data that provide a
reasonable picture of how temperature and sea level have changed since the
late 1700's. The obvious caveat here is that tide gauges and weather
stations were poorly distributed at the time of the Declaration of
Independence, but error bars can reasonably characterize the nature of the
reliability of an annual data point. Starting with this record, climate
scientists move on to basic atmospheric and oceanic physics. While the
relative impacts of various controlling factors (including "randomness")
are less-than-perfectly constrained, modelers can manipulate each within
reasonable limits to come up with a "best fit" for the observed changes in
temperature or sea level. The big assumption here is that the match
suggests that we have reasonably weighted these variables for the known
past and can, therefore, reasonably use them to model forward.
One might reasonably argue (and I have) that this approach is imperfect.
However, one can still make reasonable calculations of the magnitude of
error that a particular assumption can cause and use this to constrain the
potential errors within a given modeling scenario. At the same time. one
can also focus on the things that have changed dramatically (e.g., carbon
dioxide concentration in the atmosphere). Because these seem to dominate
the math when we do this exercise, the models appear to not be as bad as we
might have argued. In contrast, the range of C)2 values used in the various
modeling scenarios clearly show that future decisions will have a much
larger impact than natural changes over the past couple of centuries.
I will end this logical foray with two observations. First, even if one
doubles the measured changes in atmospheric CO2 prior to the industrial
revolution, the agreement between the model and the record shifts little.
In contrast, since 1900 the changes have resulted in major upward shifts in
temperature (and presumably atmospheric instability, aka 'climate change").
Thus, the models are vindicated, at least at a semi-quantitative level.
Perhaps even more telling, each successive IPCC report provides a range and
a median scenario for warming. In each report, the new "median" shifts
toward the upper end of the previous range - a pattern that might leave you
warm, but not "fuzzy" about the climate. As a colleague once argued when
his data were challenged, "You may not feel that my 19 data points going in
the same direction are statistically valid, but if you walked into a casino
and rolled craps 19 straight time, would you ask for a new pair of dice?"
Climate science is far from perfect, but it seems clear that variability
(climate change) is as important, and maybe more so than average change
(global warming). Remember that it's not the average increase of summer
temperature that is killing very old and very young folks in Chicago (or
the corals in the GFBR) - it's the extreme swings.
Happy New Year to all - and to the non-Americans, you can now relish the
knowledge that North Korea no longer has the craziest leader.
On Wed, Jan 4, 2017 at 7:47 AM, Eugene Shinn <eugeneshinn at mail.usf.edu>
> Do coral-list readers remember back when we all talked and worried about
> global warming? As I recall that was mainly before the 1998 El Nino.
> Then for about 20 years global temperature flattened somewhat and
> sometime during that time global warming became “climate change.” As a
> result of this change the subject became more confusing especially for
> the public and coral biologists. Geologist, however, have always known
> that climate has been changing. Such change is most obvious in
> Pleistocene ice core records that clearly show periodic glacial and
> interglacial (warming and cooling) periods as well as concomitant CO_2
> ups and downs. Beside ice core data recent melting of glaciers of course
> is undeniable evidence of warming. So why is it called “climate change”
> instead of climate warming? And of course we have all seen the decline
> in coral reefs. My 56-year photographic record in the Florida Keys
> dramatically show coral demise began in the late 1970s and culminated in
> the early 1980s. Unfortunately the reefs have experienced a downhill
> slide ever since.
> We have all worried about how to get our message to the public and
> decision makers. We have not done a good job of it. I suspect the term
> Climate Change has made communicating with the public more difficult.
> The problem is we have used the term Climate Change almost
> interchangeably with CO_2 /Methane and greenhouse gases. As a result the
> whole complex subject has become emotional economic and political.
> Emotions are so strong that if one questions whether CO_2 is the cause
> he or she is labeled a “Climate Change Denier.” Why not CO_2 or Carbon
> denier? These arguments must be very confusing to nonscientists. So when
> a politician calls Climate Change a hoax does he or she really mean
> temperature has not risen or fallen in the past 100 years or do they
> mean that they do not believe CO_2 and other greenhouse gases are the
> cause? These become difficult questions when we don’t clarify what we
> mean. Regardless what skeptics may believe they are nevertheless branded
> climate deniers and compared to those who believe the Earth is flat.
> Good scientists have always been skeptics regardless of the subject.
> The recent election has multiplied our concerns and postings on the list
> continue to confuse global warming with climate change. The term Climate
> change logically means temperature can go down as well as up. So why
> can’t we just say what we mean? To make the subject even more confusing
> many have begun to say carbon is the major cause of warming when they
> should be saying Carbon dioxide. As scientists we like to see evidence
> based on a controlled experiments. Those are experiments where we treat
> X number of organisms with varying amounts of a substance B, and compare
> results with X number of subjects not treated with substance B. I
> realize that’s old-fashioned scientific proof but it is straightforward
> and even the most ardent skeptics can understand the results.
> Unfortunately we cannot perform these kinds of straight experiments. We
> lack reference planets the same distance from the sun as earth to serve
> as a reference. What we have done is show experimentally in the
> laboratory (as did Svante Arrhenius back in 1896) that raising CO_2
> levels increases adsorption of infrared radiation and thus raises
> temperature. We then infer (note I said infer) that CO_2 also raises
> atmospheric temperature as it does in laboratory experiments.
> We know the computer climate model outputs are mathematically correct
> but do we really know they accurately replicate nature? A little bias
> one way or the other can influence the outcome. One should also be
> suspicious because many models (there are more than 20) is that while
> CO_2 has continued to rise since 1998 global temperature did not rise at
> the rate predicted by most models. The public and many politicians are
> often reminded of these problems so it is no wonder that many are
> confused and remain skeptical. I am confused as anyone. The message in
> the Australian youtube does not clarify the problem for most of
> us..<https://www.youtube.com/embed/BC1l4geSTP8> I suggest we drop the
> term climate change and say what we mean-----global warming.Gene
> No Rocks, No Water, No Ecosystem (EAS)
> ------------------------------------ -----------------------------------
> E. A. Shinn, Courtesy Professor
> University of South Florida
> College of Marine Science Room 221A
> 140 Seventh Avenue South
> St. Petersburg, FL 33701
> <eugeneshinn at mail.usf.edu>
> Tel 727 553-1158
> ---------------------------------- -----------------------------------
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Chair, Dept of Geology-Oberlin College Oberlin OH 44074
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