2010-10-28 09:00:56New rebuttal idea

"What if it's just a natural cycle?" This is something I hear a lot, not from hardcore deniers as much as passive newspaper-readers with little science education (most recently, my boyfriend's grandmother, who is very sweet), or even people with B.Sc's who never took a geoscience course (most recently, my high school physics teacher, who always sort of scared me, and I still regret not going to talk to him after he announced this in class last year).

Because it's a more well-known objection, even if it's less trumpeted by deniers (think "urban myth" instead of "nasty rumour"), I think it might be something to focus on. It represents a misunderstanding about the nature of forcing and response - the idea that there is some perfect temperature that the climate oscillates around in a sinusoidal curve, something like that. I think it was popularized because the only past climate change many people know about is the glacial-interglacial cycle. The forcing is cyclical, so the response is cyclical. But, because most people don't know what causes ice ages, they assume that all climate changes are cyclical, regardless of the nature of the forcing.

I have been very busy recently with midterms (sorry for the lack of activity on SkS....it has been all I can do to keep up with my blog....) but I think that this would be a fun project to do in the coming weeks when I have a little bit more time. John, could you add it to the list, and I will claim it? Or is there somewhere I can add it myself? 

2010-10-28 09:36:24It's added - #136
John Cook


Would be great to cover this as I've only covered the 1500 yr natural cycle argument.

BTW, cool interview with Ben Santer, great stuff. All that targeting from skeptics is a sign that you did a real good thing.

2010-10-28 09:52:07cycles
Dana Nuccitelli

Argument #21 used to be "it's just a natural cycle", but it got changed to the 1500-year cycle specifically just because it was rather overwhelming to try and cover all 'natural cycles'.  You can read through the discussion on the subject in the 1500 year cycle basic rebuttal thread.

I think the basic and perhaps intermediate versions of "it's a natural cycle" would be manageable.  In the advanced version I think we would want to discuss all known 'natural cycles' and how we know they're not causing the current warming.  A major undertaking.

2010-10-28 10:32:07My advice
Robert Way

First of all, good luck on your exams!

My advice to you on this topic is to be very careful. Part of the current warming can likely be explained by millennial scale climate variability (try Viau et al. 2006 or Bond or many other papers), certainly not all but part. There is supposedly a roughly 1000 year cycle (900-1100 year I thought...) that caused the RWP and MWP... The question that keeps coming up is really what orbital configuration do we have right now. If we are headed towards another ice age then the cycle is superimposed on a strong cooling trend but if we have a 30,000 year wait then we cant take much out of the amplitudes of the spikes. That being said, I think it would be a really interesting post and something that would be enjoyable to read. Climate fluctuations is essentially the last defense of the skeptics afterall...
2010-10-31 08:06:58

I agree, it would be best to start with basic and intermediate versions, focusing more on the mentality that "climate changes on its own" than going into detail about millenial climate forcings...I'm not very well-versed in that area (although I have heard a little about the debate as to what the glacial cycles would have been like without GHG forcing - cool stuff), so someone else should probably take the advanced version.

Midterms went pretty well, some were harder than I expected, some were easier. I hope to be able to get to work on this before too long...but don't be surprised if it's Christmas by the time it goes up...:)