Roy Spencer: Svensmark effect at least 2.8 x TSI forcing

Posted: May 20, 2011 by Rog Tallbloke in solar system dynamics

Dr Roy Spencer has finally come off the fence regarding the Svensmark effect: the theory that solar modulation of galactic cosmic rays affects levels of cloud cover, and therefore insolation levels at Earth’s surface.

http://www.drroyspencer.com/2011/05/indirect-solar-forcing-of-climate-by-galactic-cosmic-rays-an-observational-estimate/

Roy says:

I fitted the trend lines to get an estimate of the relative magnitudes of these two sources of forcing: the cosmic ray (indirect) forcing is about 2.8 times that of the solar irradiance (direct) forcing. This means the total (direct + indirect) solar forcing on climate associated with the solar cycle could be 3.8 times that most mainstream climate scientists believe.

If this is anywhere close to being correct, it supports the claim that the sun has a much larger potential role (and therefore humans a smaller role) in climate change than what the “scientific consensus” states.

This is progress!

Comments
  1. Roger Andrews says:

    “If this is anywhere close to being correct, it supports the claim that the sun has a much larger potential role (and therefore humans a smaller role) in climate change than what the “scientific consensus” states.”

    The Shapiro paper (http://arxiv.org/PS_cache/arxiv/pdf/1102/1102.4763v1.pdf) shows a TSI increase of about 4 w/m2 since 1900, which equates to about 0.7 w/m2 of effective TOA forcing after allowing for geometric and albedo effects.

    Amplifying this by Spencer’s 3.8 factor gives 2.7 w/m2. This is more than enough to explain ALL of the post-1900 warming.

  2. Doug Proctor says:

    Combined with the Archibald idea of a Dalton-level sunspot lull leading to a 2C temperature decline (at the US-Cdn border), we have a prediction and a mechanism that is, unlike the Hansen-Gore “projections”, falsifiable over the next few years.

    We’re getting game changers. The public cannot ignore the situation when both sides say that by 2020 (or even 2015) significantly different things will occur. Someone is going to be saying, “Oops.” (The one with research grants, without doubt.)

  3. tallbloke says:

    Roger: Shapiro makes clear that there is a large uncertainty, and that their technique and results outline one end of the possible range. If we go somewhere in the middle between them and Svalgaards flatline sun we see a forcing in line with my own estimates, which are consistent with ocean heat content increase.

    Doug: If Archibald’s interpretation of the LFC SCL theory is right we will see a big decline in surface temperature from 2013-2015. Not too long to wait now.

  4. tallbloke says:

    WUWT posted the Spencer article soon after the talkshop: I commented on Leif Svalgaards criticism here:
    http://wattsupwiththat.com/2011/05/20/indirect-solar-forcing-of-climate-by-galactic-cosmic-rays-an-observational-estimate/#comment-665094

    The comments could get lively if Leif is on form…