Wie konnen (sollen) Wissenschaftler ihre

Ergebnisse verantworten gegenuber nicht-Wissenschaftler?

Case study: the Hockeystick

Nanne Weber (1989-1992 am MPI)

• A climate scientist is an authority. Some are better in communication than others • Communication=how can I explain science to a layperson• Big question= how do I deal with bad (stupid) journalists • Central point: wir haben recht

Communication – early 1990

IPCC FAR: Schematic diagrams of global temperature variations since the Pleistocene on three timescales (the last million yrs, the last 10,000 yrs and the last 1000 yrs)

The beginning – tentative

IPCC SAR: Decadal summer temperature index for the Northern Hemisphere (Bradley and Jones, 1993) based on 16 proxy records from N. America, Europe and E. Asia. Instrumental data are 50-yr smoothed.

The next step– growing confidence

IPCC TAR: Millennial NH temperature reconstruction for the warm season (purple, green) and annual mean (black; 2- error bars shaded) and annual instrumental data (red). All data are 40-yr smoothed

The finale– quantified! Error bars!!

Hockeyteam (2005)

The beginning

realclimate.org: ‘nearly a dozen proxy-based reconstructions by different groups show qualitatively similar behavior’ climateaudit.org: ‘they are all based on the same data’

Communication – 2006

Data overlap: 1000-yr long records

Site locs #records

Ref Where

Jones et al., ‘98 yes 4 Yes, but no

Mann et al., ‘99 yes (PCs: no)

9 and 3 PCs

Yes/no No/yes

Crowley&Lowery,‘00

no 15 yes no

Moberg et al., ‘05 yes 11 yes no

Esper et al., ‘02 no 5 no no

Briffa, ‘00 no ? no no

Site maps from Mann et al. (1998), Huang et al. (2000)

and Moberg et al. (2005)

Data overlap: the answer