The value of this identity is that it shows us three essential components of
the world’s annual emissions of greenhouse gases. Each time annual
GHG emissions increase, at least one of the three components must also
have increased. There has been either an increase in GDP, an increase in
the energy intensity of GDP (Energy/GDP), or an increase in the GHG
intensity of energy (GHG/Energy). Conversely, if we are to reduce the
world’s annual GHG emissions, then at least one of these three
components must fall. Let’s consider these three components in turn and
determine which specific route to reducing global GHG emissions
appears to be most promising.
Reducing Global GDP
It should not be surprising that, ceteris paribus, GHG emissions rise when
GDP rises. The production of most goods and services requires the use of
energy, and a great deal of the world’s energy use is associated with the
release of greenhouse gases.
For two reasons, it is unrealistic to consider a reduction in the world’s
GDP as a fruitful approach to reducing global GHG emissions. First,
based on current trends, the world’s population will rise from its current
7.6 billion people to approximately 10 billion over the next century.
These 2.4 billion extra people will require more GDP just to be fed,
clothed, and housed, not to mention to receive the various “extras” that
most of us take for granted.
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