What natural cycle are deniers talking about?

I've asked similar questions before and have never recieved an adequate response that answer the question. Let's try again seeing there have been increasing claims pointing to natural cycle being responsible for the earth's increase in temperature.. We hear over and over "its a natural... show more I've asked similar questions before and have never recieved an adequate response that answer the question. Let's try again seeing there have been increasing claims pointing to natural cycle being responsible for the earth's increase in temperature..
We hear over and over "its a natural cycle" when deniers are trying to spread their disinformation about anthropogenic global warming. The IPCC states in the AR4 Chap.2 Page 131-
"The combined anthropogenic RF is estimated to be +1.6
[–1.0, +0.8]2 W m–2, indicating that, since 1750, it is extremely
likely3 that humans have exerted a substantial warming
influence on climate. This RF estimate is likely to be at least
five times greater than that due to solar irradiance changes. For
the period 1950 to 2005, it is exceptionally unlikely that the
combined natural RF (solar irradiance plus volcanic aerosol)
has had a warming influence comparable to that of the combined
anthropogenic RF."

(the term “Exceptionally unlikely” is the highest level of confidence that the IPCC assigns. It means they believe that there is < 1% probability that the science is inexact. AR4 Uncertainty Guidance Note for the Fourth Assessment Report)

And on page 132 of the same chapter-
"The direct RF due to increases in solar irradiance since 1750
is estimated to be +0.12 [–0.06, +0.18] W m–2, with a low level
of scientific understanding. This RF is less than half of the TAR
estimate.
— The smaller RF is due to a re-evaluation of the long-term
change in solar irradiance, namely a smaller increase from the
Maunder Minimum to the present. However, uncertainties in
the RF remain large. The total solar irradiance, monitored from
space for the last three decades, reveals a well-established cycle
of 0.08% (cycle minimum to maximum) with no significant
trend at cycle minima."

In other words, it's not the sun. In the back of this one chapter you will find seventeen pages of references to studies that have passed peer review.

So, if it's not the sun what is this mysterious natural cycle that deniers claim to be at work warming the planet.
To answer this question properly you will need to back up your claim with a reference to peer reviewed studies. If you don't back up your claims then your answer would not be valid and considered nothing more than pseudo science designed to mislead.
http://www.ipcc.ch/ipccreports/ar4-wg1.h...
9 answers 9