Geoscience Reference
In-Depth Information
standards for motor vehicles (discussed shortly), and for setting emis-
sions standards for new power plants.
There are currently many estimates of the social cost of carbon. A
U.S. government report provided a best estimate of about $25 per ton
els, as I show next, so I use this as the target price in the discussion
that follows.
A second approach used to determine an appropriate carbon price is
to employ integrated assessment models. For example, we might esti-
mate what trajectory of CO
2
prices would be required to attain a given
temperature objective. Figure 33 shows an example, where for these
consistent with Chapter 18's discussion of cost-benefi t analysis.
200
180
Maximum
Average
Minimum
160
140
120
100
80
60
40
20
0
2020
2030
2040
2050
Figure 33.
Illustrative carbon prices needed for a 2
1
⁄
2
°C temperature limit. This fi gure
shows target price paths for CO
2
that would lead to a maximum temperature rise of
around 2
1
⁄
2
°C. These results are from a group of thirteen models and show the central
tendency as well as maximum and minimum required carbon prices across models. The
path assumes full participation and effi cient policies.
