Here is that famous 'Al-Gore' plot of CO2 and
          temperature in the last 800 thousand years (here now also
          includes CH4, methane, another strong greenhouse gas):
          
        
        
        
         
        Taken from Ref.
          [1]
          
          
          Some comments:
          
        1)
          First of all, proving a mere correlation does not show which
          one is causing which one. The classical problem of
          cause-and-effect. If we look in detail in the data, we see
          that CO2 is lagging behind temperature. That makes temperature changes
            the cause and not the effect of CO2 changes!
            
          
        
        Image above is a zoom in to
          some detail of above plot. CO2 lags behind T.
          Data form PANGEA project, image from Ref. [6]
          
          The data have later been reanalyzed and, upon closer scrutiny,
          the lag between temperature (T) and CO2 is about a thousand
          years. Below is an excerpt of a paper of Indermühle, et al. from 2000 [7]:
          
        
        
           
        
           
        
        
          
            
              So, now it has been
                  established that CO2 is actually lagging behind
                  temperature. This closes the subject on Anthropogenic
                  Global Warming. There is no need to discuss further
                  until this point is resolved. 
                     
                  Apart from the fact that the data tell us this,
                  it is also very easy to understand. See image on
                  right. T causes CO2. This is a very plausible
                  explanation of the data. It is called Henry's Law, the
                  ratio between the concentrations of a certain gas in
                  the ocean and the air above it are constant depending
                  on temperature. When oceans and land masses are
                  warming up they are out-gassing. When the oceans heat
                  up, they liberate gas, just like boiling water for tea
                  liberates gasses contained within the water. In this
                  model, it does not make sense to think that increasing
                  the amount of gasses above our tea will increase its
                  temperature. Likewise, increasing CO2 in the
                  atmosphere will not significantly increase the
                  temperature of the oceans or the air. 
                  The out-gassing of oceans is a process in the time
                  scale of 100-1000 years because of the large body of
                  water and the long time it takes to heat up. 
                 | 
                
               | 
            
          
        
        
          2) The same correlations are
          not seen on longer or shorter time scales. On a short time
          scale there is no correlation. Above figure: 180-280 ppm CO2
          swing is associated to a -12-+2 oC temperature
          swing, so we have a sensitivity of about 1 degree per 10 ppm.
          The current level of 392 ppm would increase temperature
          further +10 degrees. The greenhouse effect is a rather
          instantaneous effect (as fast as heating up and cooling during
          the day-and-night). At best a tiny (<< 1 degree) is
          observed. The blue line does not follow the green line.
          
          In a figure:
        
        
           
        
          The statistical correlation is poor-to-absent (apart from two
          peaks at 1850 and 1940, there is nothing). Moreover, the
          sensitivity is different in this figure: a CO2 swing of 160
          ppm is translated into a temperature swing of only 0.6
          degrees. Or, in other words, 1 degree per 300 ppm (30 times
          less).
          Note also that the two points of correlation (1850 and 1940)
          again show that CO2 is lagging behind. But, anyway, on this
          time scale no correlation between T and CO2 is expected
          because out-gassing is a process that occurs on the time scale
          of centuries to millenniums. Only in the time scale of
          thousands of years do we expect a correlation.
          
          The only data that are regularly presented to you are the
          Mauna Loa data (green line). Why do you think that is so? In
          any case no correlation between (Mauna Loa) CO2 and T is
          observed.
          
          On a much longer time scale the following is observed (Note that the Al-Gore plot shown
          in the beginning is less than a pixel of this image):
          
        
        
         Image taken from Ref. [2].
          Note the 7000 ppm CO2 concentrations (20 times more than now,
          1900%). That while temperatures were the same. On the long time scale there is
            no correlation between CO2 and temperature.
          
          Similarly:
          
        
        
        
          We see that there exists a very plausible alternative instead
          of CO2 as a driving force on a long time scale, namely cosmic
          rays driving the climate. Moreover, in this case it is clear
          which one is cause and which one is effect. (It would be very
          difficult to explain how the temperature on Earth would have
          influence on the cosmic ray intensity).
          Cosmic rays change the cloud cover of our planet by ionizing
          air particles which function as water-condensation nuclei
          (think of a cloud
            chamber) and hence change the temperature.
          
          Note that politicians are trying to cover up this story:
          The chief of the world's leading physics lab at CERN in Geneva
          has prohibited scientists from drawing conclusions from a
          major experiment. The CLOUD ("Cosmics Leaving Outdoor
          Droplets") experiment examines the role that energetic
          particles from deep space play in cloud formation. CLOUD uses
          CERN's proton synchrotron to examine nucleation.
          CERN Director General Rolf-Dieter Heuer told Welt Online
          that the scientists should refrain from drawing conclusions
          from the latest experiment. Heuer says, "That would go
          immediately into the highly political arena of the climate
          change debate. One has to make clear that cosmic radiation is
          only one of many parameters." Citation from Ref. [5].
        Yes, please, dear scientists, do not draw conclusions or even
        discuss things. leave that up to the politicians. They are much
        better equipped for that.
        If these CERN employees had discovered that Global Warming is
        consistent with their data, would they also have been shut up?
        What do 
you think?
        
        
          
          3) It is as good as
          impossible to explain how both CO2 and CH4 are varying in the
          same way as temperature. They cannot be both climate forcing
          and yet be varying simultaneously (what is correlating
          them?!). It is, however, very easy to explain that both are
          the result of temperature. If temperature changes, both CH4
          and CO2 in the atmosphere because of out-gassing of the oceans
          and the land.
          Take a look again at the image with the 800,000-year ice-core
          record in the beginning of this page and then the diagrams
          below (T is temperature, CO2 and CH4 are concentrations of
          these gasses in the atmosphere):
          
        
        
          
            
                
               | 
                
               | 
                
               | 
            
            
              Both CO2 and CH4 climate
                  forcing. Enigma: How is the statistically-proven
                  correlation between CO2 and CH4 accomplished? 
               | 
              Possible (but dubious)
                  explanation: secondary-effect CO2 causes T and T
                  causes CH4 through out-gassing (or possibly other way
                  around) 
               | 
              More likely explanation
                  (once we have admitted that down-arrow correlations
                  are permissible): T
                    causes both CO2 and CH4 
               | 
            
          
        
        
          
          4) There has been more CO2 in
          the atmosphere very
          recently:
          
        
        
         From Beck [3]
          
          Note that in 2010 the CO2 concentration is about 390 ppm,
          about the same as in 1941. This had no effect on the climate.
          These data are removed from standard presentations to program
          the people into believing the catastrophic climate models.
          
        5)
          It has been suggested by some IPCC members and followers that
          sulfates (aerosols injected into the atmosphere by -- yet
          again -- human activity, namely industry) are causing a
          cooling of the planet, thus offsetting the warming trend of
          the CO2 greenhouse effect. According to them, this might
          explain the dip in temperature in the middle of the 20th
          century and why the temperature is not rising as fast as
          expected (see the failure of
            IPCC predictions).
          However, this reasoning is impossible to maintain.
        
         
           
         Image from Ref. [4]
          The above picture shows the aerosol injection and
          concentration in the atmosphere, supposedly responsible for
          cooling and offsetting the CO2 green-house effect. This
          picture shows that it is difficult to attribute the cooling
          since 1950 and warming since 1970 to a reduction in sulfur
          emissions removing the offset of green house gases.
          Aerosols have not disappeared from the atmosphere. Of course,
          it might theoretically be so that there was an ultrafine
          balance between aerosol cooling effects and CO2 warming
          effects, the balance that was removed the moment aerosols
          leveled off and CO2 continued their rise. And, I am sure, it
          is possible to simulate this, adjusting the forcing factors of
          the two until the model coincides with the data. That does not
          take anything off the problem that this fine balance is rather
          dubious to start with. Moreover, with CO2 still being on the
          rise and aerosols declining, the temperature should then have
          sky-rocketed in the beginning of this century. Which it
          didn't. It is more likely that either CO2 or aerosols are more
          important climate forcing and until one is significantly
          more/less abundant than it is now, that one will win. In other
          words, either CO2 causes significant warming or aerosols cause
          significant cooling, but not both!
        
        On the other hand, if you believe in this aerosol argument and
        believe we are doomed by a heating planet, you have the solution
        in your hands: increase pollution of industry. Subsidize aerosol
        emissions to compensate the CO2 emissions!
        
 
          
        
        
[1]
http://www.igbp.net/publications/policybriefsforrio20summit/policybriefsforrio20summit/interconnectedrisksandsolutionsforaplanetunderpressure.5.20d892f132f30b443080001954.html
        [2] Geocraft.com
        [3] http://www.biomind.de/realCO2/
        [4]
        http://tamino.wordpress.com/2010/08/23/antrhopogenic-global-cooling/
        [5] http://www.theregister.co.uk/2011/07/18/cern_cosmic_ray_gag/
        [6] Stallinga, 
De mythe van
          klimaatsveranderingen, Lulu.
        [7] A. Indermühle, et al., Geophysical Letters, vol. 27, p.
        735-738 (2000).
        
        For more information, contact me at The University of The
        Algarve, 
        
        
Prof. Peter Stallinga
        
        http://www.stallinga.org