Don't miss this Nov 1999 UEA email (5309) : "All climate change signal detection and attribution studies to date have assumed a model-based estimate of natural climate variability. This is a major and relatively untested assumption to make, and is potentially a major source of criticism"

Email 5309

date: Tue, 02 Nov 1999 14:54:55 +0000 from: Tim Osborn subject: Summary of HC-CRU discussions 29/10/99 to: Simon Tett ,matcollins@meto.gov.uk,k.briffa@uea

...---------------------------------------------------------- Summary of discussions between HC & CRU (Norwich 29/10/99)Mat Collins, Simon Tett, Keith Briffa, Tim Osborn

...So, a brief rationale for an EU proposal might be (paraphrased from Simon):"All climate change signal detection and attribution studies to date have assumed a model-based estimate of natural climate variability. This is a major and relatively untested assumption to make, and is potentially a major source of criticism that could be used to detract from all such studies. The relative shortness, and possible contamination by anthropogenic signals, of the instrumental climate record hinders an assessment of levels of simulated variability on decadal to century time scales.