Environmental Engineering Reference
In-Depth Information
4
A2
3
A1B
2
B1
1
20th Century
0
-1
1900
2000
2100
Year
rst-century temperature
increases. The best estimate average temperature change from the
year
fig. 5.1
IPCC projections of twenty-
predicted for three of the
IPCC scenarios from the collection of different models as shown in
the Fourth Assessment Report. The solid line is for scenario A
to
relative to the year
,
the dashed line for A
. Also shown are the
historic data for the twentieth century. (Adapted from Climate
Change
B, and the dotted line for B
: The Physical Science Basis. Working Group I Contribution to
the Fourth Assessment Report of the Intergovernmental Panel on Climate
Change, Figures SPM.
and SPM.
.© Cambridge University Press)
Climate change science is still evolving, and different
groups give different weights to different phenomena.
To me this is one of the strengths of the system. The
independently developed collection of models from many
groups minimizes the risk that a not-well-founded major-
ity view would dominate the analysis.
Figure
analysis. The graph shows the historic data from the
.
gives some of the results of IPCC
'
sAR
