Climate Change And Thermodynamics
Some personal thoughts
Science is not democratic. You may be entitled
to an opinion, but you are not entitled to any respect for it unless
you have demonstrated that you understand the fundamentals. There is
much propaganda on the internet. Some sites, covertly funded by oil
companies and their allies, simple have the aim of confusing the
public to protect their own pecuniary interests. One tactic is to
put a document online which purports to be a reasearch paper, but which has not been peer-reviewed,
and hence does not state the authors' qualifications, field of
competence, financial backing, or whether the methodology/honest use of
data has been independently checked.
This may be accompanied
by data and graphics which purport to prove the author's propositions,
but actually do no such thing, being merely a graphic restatement of
the authors' propostitions. Here are links describing the
controversy surrounding such alleged research:
These non-peer reviewed papers are often
uncrtically cited as "science" by the less subtle footsoldiers of the
sceptic movement, or by politions/economists with a non-science
background. Most climate-sceptic websites are fanatic paranoid
ill-informed garbage, peddling such misinformation, together with
misquotes from bona fide sources, and then coming to conclusions which
display their own ignorance
of the basic principles.
For example, anyone who proclaims triumphantly "The sun drives the climate" doesn't
understand the science or the debate. Nobody has ever suggested
differently: Without the sun we would be close to absolute zero
(-273°C). But the greenhouse effect is real AND GOOD (at least for us
on Earth, see the first link at the end of the document). Without it
the earth would be uninhabitable by us (in our present form). Here is
an extract from Encycolpedia Britanica (1997 edition)
“Trace gases, carbon dioxide and water vapour in particular, play an essential role in terrestrial climate. In the absence of these molecules that absorb strongly in the infrared, the surface temperature would be about 40 K colder than it is today. The oceans would be frozen over, and life as we know it would be impossible. There is an important synergism between CO2 and H2O. Carbon dioxide itself absorbs only a small fraction of the heat radiated by the Earth's surface. Water vapour is much more significant. The abundance of H2O, however, is controlled ultimately by temperature. An increase in CO2 may be expected to cause an increase in temperature, which allows more water vapour to enter the atmosphere and leads to a further increase in temperature. ”
“Atmospheric carbon dioxide concentration remained fairly constant over the past thousand years until the late 18th century and has been rising steadily ever since.”
From W.M. Post, F. Chavez, P.J. Mulholland, J. Pastor, T.H. Peng, K. Prentice, and T. Webb III, "Climatic Feedbacks in the Global Carbon Cycle," in David A. Dunnette and Robert J. O'Brien (eds.), The Science of Global Change: The Impact of Human Activities on the Environment, American Chemical Society Symposium Series 483, 1992
All other things being equal, the historical
increase in CO2 would be very significant. And indeed, the climate in
some parts of the world, especially near the poles is changing in an
unprecedented way. Of course the activity of the sun has changed before
and will undoubtedly change again, not to speak of the unpredictable
effects of volcanic eruptions etc. The questions are: 1) Is the climate
2) Is human activity partly or wholly responsible
3) What, barring unpredictable astronomical
effects is likely to happen in the next 100 years or so, and what, if
anything, can we do about it?
Now, I am not personally qualified enough to
answer any of these questions definitively. (Nor, most certainly, are
those climate-sceptics who make the loudest noise.) Therefore, I have
to rely on work and data supplied by others, not a situation I am
comfortable with. However, it seems clear to me that climate
change is happening. The strongest evidence is the unprecedented
glacial and polar melting. More violent weather patterns may well be
occurring too, but I don't have the tools or the data to demonstrate
The theory of the man-made greenhouse effect
is essentially that the (continuing) increase in CO2 and other
greenhouse gases has led to an increase in the amount of heat retained
by the atmosphere, and that this will impact adversely on the natural
world and upon human life. Now to the nitty gritty.
It is understandable that commentators focus on temperature, but
actually it is important to look at the bigger picture. The
macro-atmospheric system is actually composed of very many
A small increase in the amount of energy in any one of them would have effects described by an equation like the following one:
ΔE = ΔF + TΔS + SΔT
is the total energy, F is the “free energy”, T is the temperature, and
S is the entropy of the system. “Δ” refers to a corresponding
small change in any one of these quantities.
There are different definitions of total energy and free energy. Which you use depends upon the nature of the microsystem.
The total effect upon the macrosystem could be
modelled qualitatively, as a first approximation, as the sum of the
effects of the microsystems. So what does the equation above tell us?
Free energy is the capacity of a system to do
work. Work in the context of climate means “weather” - winds, rain,
storms etc, as well as ocean currents and other phenomena. All this has
a feedback to both entropy and temperature,.
Entropy is the really crucial concept here.
It is a measure of the disorder of a system, and its capacity to absorb
and transmit energy. For example, a solid metal has an organised
crystalline structure and low entropy, compared to, say, glass. So a
metal is a good heat conductor, as well as heating up and cooling down
quickly compared with glass. But glass, with its higher entropy, has a
much greater capacity to absorb heat than most metals do.
In general, liquids have more entropy than
solids and gases have more entropy than liquids. In fact, when the
phase of a substance is changing, ie at a boiling point or melting point,
you can add heat to a system without the temperature rising. For exmple, adding energy to melting ice causes a rise in entropy without there being a rise in temperature: ie TΔS is positive but SΔT is zero. This continues until all the ice has melted.
Some commentators have recently remarked that
the previously observed rise in global temperature seems to be
levelling off, and that this “disproves” global warming. However, IF this levelling is corroborated, given
the observed melting of icecaps and glaciers, it could well be
accounted for by the entropy increases associated with massive areas of
phase change (ice melting), rather than any levelling off of heat absorption by the the
atmosphere and oceans.
To summarise, you cannot understand climate
change without considering both free energy and entropy, as well as
temperature. I am not qualified to reach definitive conclusions, BUT
unlike most of the sceptic propagandists, I do have some knowledge of the
basic principles. If you don't understand what I have written here, then please “shut the fuck up” until you've done your homework!
Now, even if man-made global warming is real,
it doesn't mean that there aren't vested interests trying to exploit it
and make a fast buck on its coattails; nor does it mean that all
government responses are fully thought out and rational. Two
examples: I have nothing against wind energy, but I really don't
understand why there has been such an emphasis on it in the UK, as
opposed to the seemingly far greater potential of tidal stream energy.
Also, there is no point in limiting carbon emissions in the UK or EU
whilst importing vast amounts of goods made with dirty coal energy from
China. At the very least we should put a suitable import tariff on such
imported goods. In fact, given the unfair nature of trade with China
due to their quasi slave labour practices and currency manipulations, I
would go much further. But that is another issue.
Neil deGrasse Tyson explains the discovery of Climate Change and the Greenhouse Effect - on Earth and in Venus.
Neil deGrasse Tyson On Global Warming