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Here I try to succinctly describe the main problems with the
global warming theory:
1. Any upward temperature trend is minuscule at best
and imaginary at worst.
2. It is normal for the Earth's temperature to vary.
3. Longer-term temperature histories cannot be
determined within the degree of accuracy required to detect temperature
4. There is no empirical evidence that carbon dioxide
drives changes in temperature
5. The sensitivity of the climate due to feedbacks has
been grossly overestimated.
6. Climate models have no ability to predict.
1. Any upward temperature trend is minuscule at best and
imaginary at worst.
Here is a graph of the temperature data 'anomaly' from satellites
Satellite temperature difference from average from 1979 to June 2008
There is no obvious or significant trend in this data series. As of this
writing, the 'anomaly' (which is a fancy way of saying difference from
the average) is essentially zero.
2. It is normal for the Earth temperature to vary.
In the 1990 IPCC (International Panel on Climate Change) report,
the following figure was included:
Figure 2. From IPCC 1990 Figure 7c. -- Showing a schematic of
temperature changes over 1000 years including the "medieval warm period"
and the "little ice age"
And up until then, this was the standard view of of the Earth's
temperature history over the last millennium. Sometime after 1990 this
view shifted and the medieval warm period was denied and/or reduced in
significance without justification. The medieval warm period is
relatively well-documented in literature spanning that time. There were
Viking settlements in Greenland now currently buried under ice, grapes
grew in Britain and the people in Europe flourished (growing from 30
million to 80 million). The global mediaval warm period is exhaustively
. A recent temperature reconstruction based on proxies (using things
that vary based on temperature to estimate temperature) shows this
period nicely (paper here
Figure 3. Estimation of past temperature variations using
Or, to take a longer-term view, take a look at the temperature history
of Antarctica going in and out of ice ages.
Figure 4. Temperature history of Vostok Antarctica
The swing in temperature from an ice age and back again can be more than
11°C. Even during the warm periods temperatures still fluctuates
significantly. Compare our current temperature changes on this scale:
Figure 5. Satellite temperatures plotted on the same scale as
3. Longer-term temperature histories cannot be determined
within the degree of accuracy required to detect temperature trends.
The satellite temperature history is the best measurement of temperature
we have; however, it only goes back 30 years. To go back further than
this we have to rely on surface stations, and temperature measurements
of the ocean taken by ships. There are many issues with these historical
temperatures, for example:
The UHI bias (and even just the error on this bias) is significantly
larger then the trend we are trying to detect.
- Surface stations are subject to what is known as the urban
heat island effect. Understandably, most stations are located in
convenient locations close to cities ( and over time, inside of
cities). Basically, stations that might have been remote at one time
slowly become encroached upon by civilization. The effect of nearby
roads, buildings, and also heat produced by air conditioners, cars,
industry, etc. has the effect of raising the temperature of these
Figure 6. Urban Heat Island Effect [Goodridge, J.D., 1996:
"Comments on Regional Simulations of Greenhouse Warming, Including
Natural Variability." Bull. AMS, vol. 77, pp. 3-4.] (see related
- Many surface stations changed location over time, changed
measuring instruments, changed environmental conditions ( such as the
type of paint used, etc.)
- Examples of the severe problems with surface stations are well
- The measurement methods used in the oceans changed
significantly over time, from extracting water using canvas buckets, to
engine intake. Canvas buckets had the effect of being cooled off as
they were lifted out of the ocean and exposed to air and wind. Depths
of measurement also changed.
- Surface stations are unevenly distributed. There is fairly
good and dense coverage in the United States, but almost no coverage in
the rest of the world.
4. There is no empirical evidence that carbon dioxide drives
changes in temperature
Contrary to popular opinion as a result of the movie "An
Inconvenient Truth", temperature changes precede changes in CO2.
The temperature change occurs first, this warms up the ocean which
releases CO2 causing the CO2 to increase. The cause and effect is
exactly the opposite of what most people believe. The delay between
temperature increasing followed by CO2 increasing is around 1000 years (
). Temperatures drive changes in CO2 and not the other way around.It is
a little difficult to see in the following graph due to the large
difference in timescales, but if you look closely you can see for
yourself that CO2 follows temperature and not the other way around.
Figure 7. Temperature changes drive CO2 changes
In addition, CO2 has likely varied much more in the recent past
then is commonly acknowledged. Direct chemical analysis of CO2
concentration was performed thousands of times between 1855 and 1957
before the Mauna Loa Observatory with its continuous monitoring became
the primary source for CO2 concentration measurements. These prior
measurements contradict assumptions of CO2 stability and its
monotonically increasing nature due to human input and so has been
simply ignored despite many of these measurements being performed by
Figure 8. CO2 as measured by scientists from 1855 to 1957
[Ernst-Georg Beck, 180 Years of Atmospheric CO2 Gas Analysis by Chemical
Methods, ENERGY & ENVIRONMENT VOLUME 18 No. 2 2007]
5. The sensitivity of the climate due to feedbacks has been
Even if one takes laboratory science and creates a simple model of how
CO2 might increase temperatures ignoring clouds, convection, and other
major features of the atmosphere -- theoretical warming due to a
doubling of CO2 is distinctly unimpressive. In order to be able to
predict crisis levels of warming, models need what is called "positive
feedback loops". In a positive feedback loop, CO2 causes some warming
and this warming increases water vapor, methane and more CO2, which
increases warming some more, and so on ...
5.1 The no feedback climate sensitivity
The Earth radiates thermal energy that exactly balances the radiation it
receives from the Sun. The equation that describes this relationship is
known as the Stefan-Boltzmann equation:
(1-r)S = σT⁴
where S is the energy coming from the Sun, sigma is a constant, r is the
reflectivity of Earth and T is the temperature of Earth. If we take a
derivative of this equation and divide by S we get:
dS/S = 4 dT/T
The nice thing about this derivation is that it is independent of
any parameters other than temperature. All other parameters are factored
into the value of T which is the current temperature of the Earth.
What this equation says is that the percentage increase in
temperature will be one quarter the percentage increase in incoming
energy. The IPCC says that the increase in incoming energy due to a
doubling of CO2 is 3.7 W/m². The current incoming energy from the sun
is 1368 W/m². The ratio of the surface area of the earth to the cross
sectional area of the earth hit by the suns rays is 4, so we divide the
raw incoming radiation by 4 to get ⇒ S = 342 W/m². The average
temperature of the earth is assumed to be around 287K. Plugging these
values into our equation gives a sensitivity of 0.21 C/W. This means
that given the additional 3.7 W from doubling of CO2 would give a total
temperature change of 0.78 C. Even though this is just a rough
approximation it is many multiples lower than any of the numbers used by
the IPCC that range from 2 to 4.5C. Actual empirical
studies estimate climate sensitivity to be negligible due to negative
feedback from clouds (something climate models do not model) [see also negative
feedback and more].
Whatever the value of sensitivity, the higher the stated value,
the more difficult it is to reconcile observed temperature changes
versus observed CO2 changes. CO2 concentration is estimated to have
approximately increased from 280ppm to 370ppm over the last century (new
data now shows that CO2 concentration depends on where you are). Climate
sensitivity to CO2 is logarithmic which means that most of the increase
in temperature should occur early on. If we are to get significant
warming, we should have seen it by now (which, according to figure 1, it
is doubtful we can claim any meaningful trend in warming at all so far).
The climate will get less and less sensitive to future CO2 changes from
here on out.
Given the current empirical evidence, it is therefore necessary to
conjure up several simultaneous arguments why CO2 is still a problem
Besides the obvious objection against these arguments in that they seem
specifically designed purely to rescue the global warming theory, rather
than accepting the much simpler likelihood that the theory is simply
incorrect, many of these arguments are incorrect and easily shown to be
- The warming that should've occurred during the last century
was suppressed by aerosols ( pollution particles in the air reflecting
- The warming that should've occurred has been largely absorbed
deep in the ocean, ready to be released later on.
- There is a strong positive feedback loop that makes the
climate very sensitive to small changes in CO2.
- Once the aerosol factor is overcome, warming will accelerate
dramatically as this feedback loop catches up and stored heat from the
oceans is released.
- The climate system is nonlinear and there is a critical
threshold ( known as the tipping point), which if exceeded will cause a
sudden and catastrophic increase in temperatures.
For a different approach to demonstrating the incorrectness of current
sensitivity numbers see
- Most of the aerosols are produced in the northern hemisphere,
but simultaneously this is also where most of the warming has occurred.
If the aerosols suppressed warming then we should expect most of the
warming to have occurred in the southern hemisphere. Instead, the
southern hemisphere actually shows a slight cooling trend.
- Sensors were placed in the ocean to test this theory in the
expectation that it would prove true, instead, the sensors have shown a
slight cooling (ocean
- If the climate is so sensitive to small changes in CO2, then
we should already be in the middle of deep and long lasting Ice Age.
Consider the figure below which shows estimates of CO2 concentration
over the last 600 million years. We are near the lowest point in CO2
concentration in hundreds of millions of years.
Figure 9. CO2 in the past
- This argument assumes that aerosols will decrease. While this
may be true in Europe and North America, China and India are more than
compensating with a growing use of coal-fired power plants that is very
unlikely that aerosols will decrease anytime soon.
- Refer to figure 3, 7 and 8. If there was a 'tipping point',
some sort of critical threshold, the Earth would have experienced it
6. Climate models have no ability to predict
We cannot point to the recent past (figure 1) to demonstrate why we
should fear CO2. We cannot point to the intermediate past (figure 3) or
even the far past (figure 7 & 9). The sole thing that can be pointed to
to justify the current hysteria over CO2 are climate models.
of the climate models include strong positive feedback loops and high
climate sensitivity which we showed to be unlikely. In 1988 Jim Hansen
of NASA stood before Congress and told of how mankind would face
catastrophic consequences if it did not immediately and drastically
reduce CO2 output. 20 years later in 2008 Hansen gave a follow-up talk
in which he admonished oil companies and skeptics as criminals and
traitors -- the global average temperature was lower that day 20 years
later than when he gave his first talk. Simply, the climate models do
not work. They did not work in 1988, they did not work in the 90s, and
they do not work now. Given our current level of understanding and
technology, climate cannot be predicted (