FACT: CO2 concentration has RAPIDLY increased, and this increase correlates to human activity- ie deforestation and fossil fuel burning:
The following data is from Vostok Ice core samples, and is confirmed by other ice core data and other independent methods:
This increase CANNOT be explained by volcanism- the isotopic ratio of carbon in the atmosphere show a similar sudden and escalating change- this change is consistent with what you would expect if this additional carbon was coming from fossil fuel burning. This change is the OPPOSITE of what you would expect from volcanism.
Here are the conclusions of a Lawrence Livermore study modeling the carbon isotope cycle in the atmosphere:
from http://www.llnl.gov/str/Duffy.html
Simulations were performed to separately assess the changes caused
by (1) land clearing and fossil-fuel burning, (2) land clearing only, (3) fossil-fuel burning only, and (4) both plus observed atmospheric data until 1990, which includes nuclear-testing 14C levels. The last simulation indicates the model's ability to portray past trends and predict future 14C fluxes.
The simulations indicate what percentages of increases in atmospheric CO2 can be attributed to deforestation and fossil-fuel burning. The data indicate that, prior to about 1910, most of the carbon entering the ocean resulted from deforestation; since that date, the carbon flux has been dominated by the effects of fossil-fuel burning.
A plot showing this isotope change can be found here:
http://www.ehleringer.net/Biology_5460/Lectures/031120.pdf
again this is backed up by other studies using other methods.
SO, IT IS A FACT THAT CO2 IS INCREASING RAPIDLY AND THAT THE CAUSE IS DUE TO HUMAN ACTIVITY- END OF STORY, THIS IS NOT DEBATABLE. ANYONE THAT SAYS OTHERWISE IS EITHER LYING OR IGNORANT ON THE TOPIC.
So, we know that CO2 is a greenhouse gas, thus it causes warming. It makes theoretical sense and is shown to be the case in ice core data (again supported by other data and other methods):
CO2 concentration IS positively correlated with temperature. THUS GIVEN THIS FACT AND THE ABOVE, IT IS THEN A FACT THAT HUMANS ARE RESPONSIBLE FOR GLOBAL WARMING-PERIOD, END OF STORY!
This warming is documented- again by many independent methods:
Now, the truly stupid will say, "well your ice core graph shows large fluctuations in the past few hundred thousand years, and we are still here- so cant be too bad a thing"
Those oscillations happened BEFORE we became a globe spanning civilization heavily dependent on agriculture! Does anyone really believe we can survive a large change without it killing billions and lowering the standard of living? Not to mention the loss of coastal cities?
Anyone who still doesnt believe in global warming just demonstrates that they are ignorant, or too agenda driven to accept the facts.