Stochastic and scaling climate sensitivities: Solar, volcanic and orbital forcings
Article first published online: 5 JUN 2012
©2012. American Geophysical Union. All Rights Reserved.
Geophysical Research Letters
Volume 39, Issue 11, June 2012
How to Cite
2012), Stochastic and scaling climate sensitivities: Solar, volcanic and orbital forcings, Geophys. Res. Lett., 39, L11702, doi:10.1029/2012GL051871., and (
- Issue published online: 5 JUN 2012
- Article first published online: 5 JUN 2012
- Manuscript Accepted: 30 APR 2012
- Manuscript Received: 2 APR 2012
- climate sensitivity;
- nonlinear geophysics;
 Climate sensitivity (λ) is usually defined as a deterministic quantity relating climate forcings and responses. While this may be appropriate for evaluating the outputs of (deterministic) GCM's it is problematic for estimating sensitivities from empirical data. We introduce a stochastic definition where it is only a statistical link between the forcing and response, an upper bound on the deterministic sensitivities. Over the range ≈30 yrs to 100 kyrs we estimate this λusing temperature data from instruments, reanalyses, multiproxies and paleo spources; the forcings include several solar, volcanic and orbital series. With the exception of the latter - we find thatλ is roughly a scaling function of resolution Δt: λ ≈ with exponent 0 ≈ < Hλ ≈ < 0.7. Since most have Hλ > 0, the implied feedbacks must generally increase with scale and this may be difficult to achieve with existing GCM's.