The contradictory nature of global warming skepticism

A major challenge in conversing with anthropogenic global warming (AGW) skeptics is that they constantly seem to move the goalposts and change their arguments.  As a consequence, they also frequently contradict themselves.  One day they'll argue the current global warming is caused by the Sun, the next that it's "natural cycles", the next that the planet is actually cooling, and the next day they'll say the surface temperature record is unreliable, so we don't even know what the global temperature is.  This is why Skeptical Science has such an extensive skeptic argument list.

It should be obvious that the arguments listed above all contradict each other, yet they're often made by the same skeptics.  As one prominent example, in 2003 physicist and skeptic Fred Singer was arguing that the planet wasn't warming, yet in 2007 he published a book arguing that the planet is warming due to a 1,500-year natural cycle.  You can't have it both ways!

It's a testament to the robustness of the AGW theory that skeptics can't seem to decide what their objection to it is.  If there were a flaw in the theory, then every skeptic would pounce on it and make a consistent argument, rather than the current philosophy which seems to be "throw everything at the wall and see what sticks."

It would behoove AGW skeptics to decide exactly what their objection to the scientific theory is, because then it would be easier to engage in a serious discussion, rather than the current situation where we're basically playing whack-a-mole with the favored skeptic argument of the day, which totally contradicts the favored skeptic argument from yesterday.

Just as one example, you can't argue that the Sun is causing global warming and that climate sensitivity is low.   Solar output has only increased by about 0.1% over the past century, and the way you determine the associated global temperature change is to multiply the change in solar radiative forcing by the climate sensitivity factor.  So they only way you could argue for a significant solar warming would be if climate sensitivity is high.  You just can't have it both ways - if climate sensitivity is low, it's not just low with respect to greenhouse gases, it's also low to solar activity, orbital variations, volcanic emissions, etc.  And if it's low, then the Sun has caused less than 0.1°C of the 0.8°C warming over the past century.  Similarly, arguing for a low climate sensitivity contradicts the climate has changed before argument for the same reason.  If climate sensitivity is low, it will prevent significant climate changes regardless of the cause, whether they be anthropogenic or solar or some other natural forcing.

If you want to argue that the warming is due to a natural cycle, then pick a specific natural cycle and research it.  Make sure there's a scientific basis to your argument.  For example, don't argue that it's due to a 1,500-year cycle when the planet wasn't warming 1,500 years ago!  But most importantly, don't contradict yourself by claiming that the planet isn't warming the next day.  These kinds of flip-flops are common on Anthony Watts' blog, which had a very schizophrenic six month period:

And that's when he's not arguing that the surface temperature record is so contaminated that we don't even know if the planet is warming.  Or that this supposedly unreliable data shows cooling.

But until skeptics start making some consistent arguments, Skeptical Science has set up a page listing all the skeptic arguments that contradict each other in order to make the mole whacking a little easier.

Posted by dana1981 on Saturday, 11 September, 2010

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