Discussion Central

Subject: Global Climate Change

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  • Climate Change

1.  Global Climate Change

Posted 12-01-2016 17:34
Dear All,

My name is Norman Loney and I reviewed a great book recently related to Global Climate Change - the book is actually an introductory version of the topic and is designed to put the conversation in the technical context of Chemical Engineering. Myself and the Authors are looking to introduce this subject matter into the  classroom through a "Mathematical Methods Course". Indeed if there is to be solutions it is most likely will be coming from the next generation of Chemical Engineers and I do believe it is our responsibility to provide various "worse case" scenarios regardless of our own bias. Below, FYI, I share with you in quotation a description of what the proposed model can contribute. Your constructive feedback would be appreciated.

Thanks

Norm

"A mathematical model can be particularly informative and helpful for under-
standing what is happening.  We therefore offer an introductory global CO2
model that gives some key numbers, for example, atmospheric CO2 concentration
in ppm as a function of time for the calendar years 1850 (preindustrial) to
2100 (a modest projection into the future):

                            http://www.pdecomp.net

The model is based on just seven ordinary differential equations (ODEs) and is
therefore intended as an introduction to some basic concepts and as a starting
point for more detailed studies.  The ODEs are carbon balances for seven
reservoirs: upper atmosphere, lower atmosphere, long-lived biota, short-lived
biota, ocean upper layer, ocean deep layer and marine biosphere.

The model also includes ocean chemistry calculations that address acidification
with ocean pH typically ranging from 8.2 to 7.8 (pH decreases with increasing
acidity).  These calculations illustrate some basic numerical procedures, e.g.,
a Newton solver applied to a fourth order polynomial to calculate ocean pH and
spline interpolation to provide additional model outputs.  The problem of
acidification and CaCO3 dissolution, which has important implications for coral
and marine life, as well as ocean CO2 uptake, is addressed by the model.

A basic global warming component has been included based on CO2 buildup in the
lower atmosphere but since climate change (warming) is still a controversial
and uncertain area, the primary focus is on carbon buildup in the atmosphere
and oceans which is being measured quantitatively and is therefore undisputed.

Projected anthropogenic CO2 emissions can be varied to investigate long-term
responses (such as atmospheric ppm CO2 and ocean pH).  As an application of
the model, proposed emissions plans and goals can be evaluated, e.g., from
various international conferences such as in Paris, December, 2015, environ-
mental groups and governments.

The CO2 model is available (gratis) as a set of commented routines in Matlab
[1] and R [2] from a download link in http://www.pdecomp.net. Please
direct any questions to wes1@lehigh.edu.

[1] http://www.nytimes.com/2013/05/11/science/earth/carbon-dioxide-level-passes
-long-feared-milestone.html

http://www.nytimes.com/interactive/2013/05/10/science/crossing-a-line.html?
ref=earth

[2]  Matlab is a scientific programming system distributed by the MathWorks,
Natick, Ma.

[3] R is an open source scientific programming system that can be downloaded
(at no cost) from the Internet."


2.  RE: Global Climate Change

Posted 12-10-2016 21:32

Can somebody cite a period when climate HASN'T changed?

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Stephen Brecht, BChE



Retired



3.  RE: Global Climate Change

Posted 12-11-2016 11:16

Stephen,

It all depends upon your time scale and your definition of what constitutes "climate change".  My understanding of the Earth's climate history is that most of it has been slow transitions, and that fast transitions have been disruptive to life forms, and  particularly disruptive to larger life forms, on our planet.

In terms of the current debate, the primary concern is the potential rate of climate change, specifically temperature increase.  Mankind's ability to adapt depends not only on how much the climate may change but how quickly that change occurs.  I have no doubt mankind can handle an increase of 5 degrees Celsius over 5,000 years. This has been the average rate of the Earth's natural temperature rise after an ice age, based upon the known temperature history of the last 800,000 years.  However, we may already be within a few degrees of the warmest the Earth has been over that 800,000 year span.  An additional 5 degree Celsius temperature increase over the next 100 to 200 years, as predicted by many climate models, would be much harder to handle. 

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Henry Waldron
Principal
Private
Voorhees NJ



4.  RE: Global Climate Change

Posted 12-12-2016 09:37

Henry:

Thanks for your explanation.  Having lived for many years in the US "southwest" (I have lived in 3 of the "4-corners" states), I have encountered several "pre-historic" situations where the only explanation for a sudden failure of a society or "civilizations".  Years ago, park rangers at Mesa Verde National Park and among the Pueblo, anthropologists at digs, and just plain old amateur hobbyists expressed that it didn't make sense that a seemingly thriving society just suddenly either disappeared or left their infrastructure, apparently going from the height of development to nothing in a period of only a very few decades.  Evidence was that food sources disappeared or water was suddenly not sufficiently available after being there for centuries.  they all said that such swift changes were unexplainable.  Well, it's now apparent that such changes do and have occurred every few centuries.  Such changes are only really evident in areas or zones that are on the fringe of being able to support larger population densities, like the southwest.  Yes, these areas cover only a small fraction of the earth's surface, and may be isolated cases.  But the evidence is there.  Arguably, these conditions occurred in part because the society became too large or too successful, adding demand on the environment, and were at least in part man-made, but not unique to our current society and development.

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Bruce Bullough
Portage MI



5.  RE: Global Climate Change

Posted 12-28-2016 22:44

What I find most interesting about this discussion on Global Warming/Climate Change, is that nobody seems to recognize that we are in an inter-glacial period that started about 11000-12000 years ago, when at least half of the Northern Hemisphere was covered with ice sheets up to a mile thick.

The natural expectation would be that the temperatures of the Earth SHOULD show a warming TREND, regardless of yearly temperature fluctuations, and study of any graphs will show that that is exactly what is happening. as the planet warmed, the rate of this trend became APPROACHED a relatively straight line. As for rapidity of climate changes, there have been periods where climate has changed significantly in less than a decade; I may be wrong, but the Younger-Dryas extinction relatively soon after the end of the last glaciation was one of these extreme events.

Another problem with emphasizing CO2 concentration as responsible for Global Warming/Climate Change is considering correlation to be causation. While CO2 may be involved, few people seem to consider the changes in land use not only since the start of the Industrial Revolution, but since the final evolution of homo sapiens. Just think of how many forests have been denuded, or actually just literally cleared not only since the industrial Revolution, but by thousands of years of human existence. Ironically, some of the sources of energy to replace fossil fueled power plants, particularly solar and wind farms, would just exacerbate the problem.

------------------------------
Stephen Brecht, BChE



Retired



6.  RE: Global Climate Change

Posted 12-30-2016 15:47

Hi, Steven Brecht.  Even during the Last Glacial Maximum, which occurred about 24,500 BCE, nowhere near half of the northern hemisphere was covered in ice sheets up to a mile thick. Around 11,000 years ago, the northeast part of Canada and Greenland were covered in glaciers, with strips of glaciers elsewhere in North America. (http://www.historymuseum.ca/cmc/exhibitions/aborig/fp/fpz2f13e.shtml)  

Human civilization started with the Holocene, ~12,000 years ago. In 2013 it was hotter than 90% of the Holocene (http://science.sciencemag.org/content/339/6124/1198).

Climate scientists are smart enough to know that climate changed in the past and that land use changes could affect climate.  In fact, they use information about past climate change to learn about what is affecting today's climate and what future effects might be. There is a whole branch of paleoclimatology that focuses on previous rapid changes in climate.

There are multiple lines of evidence that point to human-caused CO2 resulting in climate change. An extremely partial list:

We know from physics that increasing the concentration of CO2 and other greenhouse gases in the atmosphere affects the earth's energy balance

We know that levels of CO2 and other greenhouse gases are high and rising: CO2 is the highest it's been in the last 780,000 years (for the last 400,000 years see http://cdiac.ornl.gov/trends/co2/graphics/vostok.co2.gif, for recent measurements see http://blog.ucsusa.org/wp-content/uploads/2014/03/mlo_full_record.png)

We know that global temperatures are increasing (http://data.giss.nasa.gov/gistemp/graphs_v3/)

We know the temperature increase is from greenhouse gases because if it wasn't, the vertical temperature profile of the atmosphere would look different (http://onlinelibrary.wiley.com/doi/10.1029/2004JD005075/full)

We know that the increase in greenhouse gases in the atmosphere is from combustion of fossil fuels, because it isn't from other sources and they're depleted in 13C (http://www.realclimate.org/index.php/archives/2004/12/how-do-we-know-that-recent-cosub2sub-increases-are-due-to-human-activities-updated/)

We also know that if we exclude anthropogenic sources of greenhouse gases, the climate models don't work (and they do work very well) (also from Santer et al 2004)

-Kirsten

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Kirsten Rosselot
owner
Process Profiles
Calabasas CA