Energy, Emissions, and Action - Beyond Smoke and Mirrors - page 110

. Reducing Emissions

The only way to reduce global greenhouse gas emis-
sions while maintaining the same economic output is to
change the mix of fuels we use, to use energy more
ef ciently, or a mixture of both. To see why this is so,

I want to expand on a way of looking at things that
Iintroducedin Chapter . There I discussed a way to

get at energy demand in the seemingly roundabout way
of considering GDP (the size of an economy), and
energy intensity (the amount of energy used to produce
a unit of GDP). The amount of energy used by a
country, a region, or the world could be determined
from

Energy ¼ GDP (Energy/GDP).

This formulation is useful for energy because we
know (or at least think we know) how to predict future
GDP from projections of economic growth, and how to
predict future energy intensity from historic trends.
Iwanttodothesamesortofthingwithgreenhouse
gas emissions. The way to look at emissions is as a
product of four things: population multiplied by per
capita income (GDP divided by population) multiplied
by our old friend energy intensity (energy divided by
GDP) multiplied by a new term called emission inten-
sity (emissions divided by energy). Just like the equation
in Chapter this seemingly roundabout approach lets

us get at emissions using things that are easier to esti-
mate. This is the equation below, and if emissions are to
go down, one or more of the components of the emis-
sions equation have to go down.