Posted by: ericgrimsrud | February 21, 2014

The Simple and the Complex aspects of climate change

In understanding the science associated with climate change it is very useful to separate the most basic and well understood parts from the rest which can be very complex and challenging even for professional scientists to fully comprehend. The easy-to-understand and most basic part of climate change concerns the overall total heat balance of the Earth.  

The crust of the Earth receives and emits energy almost entirely via electromagnetic radiation (EMR).  EMR emitted by the sun (sunlight) is absorbed by the Earth and EMR in the form of Infrared Radiation (IR) is emitted back into space by the Earth.  Only a small portion of the IR emitted by the surface of the Earth passes directly into outer space, however.  Most of it is absorbed and then reemitted by the IR-active molecules in our atmosphere that we call the greenhouse gases (GHG’s).  The net effect of the GHG’s is to act as the Earth’s “insulation” – warming both our atmosphere and the surface below.  The most abundance permanent GHG is CO2 and due primarily to our combustion of fossil fuels, the amount of CO2 in the atmosphere has risen from 280 to more than 400 parts per million over the Industrial Age.  This excess CO2 will stay there for several centuries because it takes a very long time for nature to convert biological carbon (that which cycles through plants, the atmosphere, and the oceans) back to its geological forms (fossil fuels and limestone). 

Thus, the Earth is warming up and will continue to do so for a very long time as the thermal inertia of the Earth (provided mainly by its oceans and glacial ice) is steadily overcome.  Furthermore,  the magnitude of expected future warming is increasing every year as we continue to add more CO2 to the atmosphere – causing its level to rise about 3 ppm per year.  In addition, the fraction of incoming solar radiation (about 30% over the entire planet, called the “albedo”) that is reflected back into space is decreasing as our planet’s surface ice is turned into either open ocean or ground.  This effect also warms the planet – especially in the Arctic regions.

Concerning the issue of average global warming, the above tells the story – it really is that straightforward.  But wait a minute!  In response to this comment we can expect to see the  deniers of the world try to muddy the issue as much as possible in an effort to make the science involved seem far more complex, less understandable and much more uncertain than I have related above.   You will also note, however, that all of these other issues will concern how that extra energy is being spread and distributed throughout the world – thus affecting local climates.  That is a different subject, however, called “meteorology” which is, indeed, exceedingly complex and not so well understood.  Thus, we will hear a lot about things such as local surface temperatures, the El Nino and La Nina effects of the  ocean currents, the unusually cold and snowy weather being experienced here and there, and proliferation of animal and plant species here and there.  Although all of these parameters and the exceedingly important discipline of meteorology are linked to the total global heat content of the Earth, they do not affect the total heat content of the Earth.  That is, our planet will continue to heat up as described initially no matter how, where, and when that extra energy is distributed.

So what can be done about stopping our ongoing increase in the total heat content of the Earth?  The answer to that question becomes very clear, does it not, when proper attention if given to central cause of that heat increase.  Concerning the CO2 we have already put into the atmosphere – probably relatively little can be done – we will undoubtedly have to learn to live with the heat increase we already have as well as  that which already is in the pipeline.   But concerning the additional CO2 we will be putting into the atmosphere in the future, we have the option of doing a lot – the future cumulative emissions of CO2 is, in fact, the only parameter we have any control over.

A potential rub here will depend on what sort of “solution” will be viewed as having the “least impact on our quality of life”.   If we are concerned only with our immediate, short-term future, we will undoubtedly continue to “party on” with business-as-usual for a couple of decades – and then just watch the Earth degrade at an even faster pace thereafter.  If we also care about future generations, however, life across our entire planet must change a great deal – starting with going “cold turkey” on our addiction to fossil fuels.  While science can certainly help us make it through that process, it is unlikely to offer easy and pain-free fixes.  The required changes will have to include that old-fashioned bit (stop the addiction) before other measures (development of carbon free energy sources) will have significant beneficial effects.  And if you happen to believe that there is no point in trying because of the increasing emissions of other countries, such as China and India, you have already given up and have effectively joined the “party on” group.

I realize that the obvious but tough solution to the global warming problem I am suggesting here will not be readily accepted my many who will continue to embrace the various “happier” versions of science being dispensed by the numerous pseudo-scientists in our midst.  You will note, however, that these deniers will invariably use details of “meteorology” rather than “the total average heat content” of the Earth in trying to confuse the issue as much as possible.  Sure,  we do not know exactly how, when, and where the effects of continuous additional heat will play out.  But we do know for certain that our planet is presently being heated up at a rate thousands of times faster than any previous point in the last  billion years.  As described in my previous post concerning “tipping points”, we also know what is sure to happen when heat-induced natural emissions of methane and carbon dioxide begin to exceed those of mankind.


Responses

  1. EPG,

    I really hope you are right.

    It would be truly wonderful if we could raise or even maintain global temperatures simply by maintaining our first world life style made possible by the “Industrial Revolution” and the fruits of scientific discovery such as electricity, the internal combustion engine or nuclear power.

    What I fear is that the present inter glacial will soon end and in spite of mankind’s scientific prowess we will be unable to cope with the next “Ice Age”. With glacial ice one mile thick where New York stands today and the greater Wisconsin glacier extending to Tennessee the USA will not be capable of feeding 300 million people.

  2. EPG,
    You said:
    “The most abundance permanent GHG is CO2………..”

    On Earth the most abundant GHG is water vapor, good old H2O.

    (Response from EPG: Good old H2O is not a “permanent” and well-mixed component of our atmosphere as CO2 is. The amount of water vapor in the atmosphere depends on temperature. As T goes up, so does H2O. Thus it is a “feedback” gas which amplifies the warming effect of CO2 and all of the other GHG’s. Note also that at the top of the troposphere where T = – 70 F, there is essentially no water vapor while the CO2 level is same as background, about 400 ppm today.)


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