Geoscience Reference
In-Depth Information
3.2. Inconsistent controversies
Observational data is very striking because they can be converted into
graphs, which are more powerful than long speeches, and which the IPCC
does not deign to call upon. Nevertheless, for the IPCC, the very high levels
of confidence in the human influence on climate warming relies on physical
knowledge. Conversely, historic data constitutes the basis of our work. This
makes it more sensitive to the diversity of paleoclimatic reconstructions than
other studies.
Figure 3.4 shows, on one side, the original M. Mann reconstruction
(graph a), and on the other side, the Moberg reconstruction (graph b). The
curves entitled hockey stick and boomerang were not drawn free-hand, but
come from pure mathematical curve smoothing.
a) b)
()
()
0.8
0.8
Hoc key stic k
Mann / HadCRUT4
a1 * u1 + b1
Boomerang
Moberg / HadCRUT4
a2 * u2 + b2
0.6
0.6
0.4
0.4
0.2
0.2
0
0
-0.2
-0.2
-0.4
-0.4
1000
1200
1400
1600
1800
2000
1000
1200
1400
1600
1800
2000
Figure 3.4. Hockey stick or boomerang?
After calibration and alignment by linear regression, the dotted lines
reproduce respectively the reconstructions of log-concentration of CO 2 (a)
and of solar irradiance (b). Obviously, the conclusions reached differ
depending on the paleotemperatures selected.
The coefficients a 1 and a 2 can be assimilated to sensitivities, respectively
to CO 2 and solar irradiance. In the “100% CO 2 ” hypothesis suggested by
Search WWH ::




Custom Search