THE ECONOMIC ORIGINS OF CLIMATE CHANGE - The Climate Casino - page 32

more rapid decarbonization, and if wisely undertaken that can be done
with modest costs. There are many technologies that can produce goods
and services with less carbon or even zero net carbon emissions. For ex-
ample, electricity can be generated with low-carbon fuels (such as natural
gas) or with noncarbon fuels (such as nuclear, solar, and wind power).
We can develop more effi cient appliances and cars. We can better insulate
our houses. At some point, we may even be able to remove CO 2 from
emissions streams or from the atmosphere inexpensively. So rather
than focusing on painful limits to economic growth, economists tend
to emphasize steering the economy toward low-carbon technologies.
Table 1 provides an illustration of a standard projection of CO 2 emis-
sions and their determinants. An important starting point is the base-
line or “no-policy” path of unconstrained CO 2 emissions. This provides
a reference or starting point for policy—a look at how the world would
evolve over the coming years with normal economic growth and unre-
strained CO 2 emissions. Basically, this estimate combines a projection
of economic growth along with the underlying trend toward decarbon-
ization, discussed above, but with no limits on CO 2 emissions.
What do the different IAMs show? For this discussion, examine a
group of IAMs surveyed under the aegis of the Energy Modeling Forum
(EMF) at Stanford University. 8 The project is called EMF-22. It included
modeling teams from around the world: six groups from Asia and Aus-
tralia, eight from western Europe, and fi ve from North America. Eleven
of the modeling teams provided results for the baseline scenario of CO 2
emissions through 2100, and they are shown in Figure 5.
In addition, I have shown as two heavy lines the average of the
EMF models along with the results of our Yale DICE model, which is
used extensively in this topic. It is useful to note that the DICE model
predicts almost exactly the same growth rate for global CO 2 emissions
over the next century as the average of the EMF-22 models.
The heavy line with triangles is the average of the eleven models
surveyed in the EMF-22 project. The heavy line with the circles is from
the Yale DICE model. The light lines are the individual EMF models. 9