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Global Warming

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 trends.
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 (original data here )

Figure 1. 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 documented here . 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 temperature proxies.

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 figure 4.

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.

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 ( reference ). 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 renowned scientists.

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 grossly overestimated

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.

5.2 Excuses

Given the current empirical evidence, it is therefore necessary to conjure up several simultaneous arguments why CO2 is still a problem worth considering:
  1. The warming that should've occurred during the last century was suppressed by aerosols ( pollution particles in the air reflecting sunlight).
  2. The warming that should've occurred has been largely absorbed deep in the ocean, ready to be released later on.
  3. There is a strong positive feedback loop that makes the climate very sensitive to small changes in CO2.
  4. Once the aerosol factor is overcome, warming will accelerate dramatically as this feedback loop catches up and stored heat from the oceans is released.
  5. 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.
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 so:
  1. 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.
  2. 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 cooling).
  3. 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
  4. 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.
  5. Refer to figure 3, 7 and 8. If there was a 'tipping point', some sort of critical threshold, the Earth would have experienced it long ago.
For a different approach to demonstrating the incorrectness of current sensitivity numbers see Monckton .

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. All 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 ( reference ).