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Chapter One - The Kaya Identity & IPAT

Carbon dioxide is a greenhouse gas that is contributing to climate change by trapping solar infra-red rays within the atmosphere and, in turn, heating up the ocean and land temperatures.  Although other gases play a role, since 2000 the dominant gas is CO2.  CO2 is the biggest headache and therefore the focus in this blog.

The 'problem' of climate change is immensely complicated but, at the same time, the solution is very simple - we need to stop emissions.  Without getting too involved in the contradictions surrounding the subject (and often hypocritical actions), resolution can be simplified into one equation, the Kaya Identity, which was developed by a Japanese energy economist of the same name, Yoichi Kaya (1993):

           F = P * (G/P) * (E/G) * (F/E) = P * g * e * f


F is global CO2 emissions from human sources;

P is the global population;

G is world GDP (Gross Domestic Product) and g = (G/P) the global per-capita GDP;

E is global primary energy consumption and e = (E/G) the energy intensity of world GDP; and

f = (F/E) the carbon intensity of energy - the volume of carbon produced per unit of energy.

Do not be put off by this mathematical equation to which we will return.  Emission reductions are dependent on one or more of the key variables F, P, G, and E so to reduce carbon emissions we must reduce one (or more) of these.

Let us take each one in turn:

Population growth (P) remains unabated and, in the absence of global warfare or pandemics, seems uncontrollable (see Chapter 6).

Economic growth (g) seems unassailable with the desire to expand wealth and GDP based aspirations of humankind.  We could do much better here, however, by focusing our growth away from consumerism towards carbon-reducing inventions.  The basic problem is that some growth is essential for technological innovation and, as a minimum, I would suggest that a rate of 2.5-3% is needed for this to have an effect.  In this context, economic growth is real economic growth with inflation adjustment (see Chapters 4 and 5).

Historically, energy intensity (e) has increased at a rate of approximately 1% per annum - so its contribution is minimal.  In some areas, we have been doing better than this, where, with a focus on energy efficiency, a rate of 2.5% has been achieved but more cannot be expected.

The full focus of policy attention has targeted carbon intensity improvement with an emphasis on lower carbon energy, renewables and, possibly, nuclear power.  Unfortunately, the rate of change required of this far exceeds anything achieved in our economic history.  The scale of the challenges is immense.  Other technologies must, therefore, contribute (see Chapters 7 and 8).

It is apparent and will be developed later in Chapters 7 and 8, that, even with the best will in the world, the possibility exists that technology intervention may be too limited and too slow to avert catastrophic global warming.  It is, therefore, time to interrogate the Kaya Identity factors.  Challenging current ideology explicitly is simple mathematics since the climate is non-negotiable.  Thus, the goal must be to reduce the absolute quantity of F in the Kaya Identity (see Chapter 2).

The impact of this on the global economy is a further question.  Our requirement for exhaustive roll-out and development of new technology is explicit.  We must also question the way we live, and our life priorities since technology alone will not be a panacea.  And all technological revolutions preface social change so we must be prepared.

The Kaya Identity, in turn, derives from the I=PAT equation - a formula put forward to describe the impact of human activity on the environment by Commoner, Ehrlich, and Holdren (1970) where:

I = the Impact on the Environment;

P = Population;

A = Affluence; and

T = Technology

As an aside, some quarters criticize the use of this equation.  Firstly, the variables are not independent of each other.  Secondly, they argue, it leads unnecessarily to a focus on population when in fact the other variables in the equation need to be disaggregated and examined.

However, I defend its use here whilst recognizing some limitations.  It is useful as a general framework for understanding the glocal problem while at a country level it can provide useful insights once net migration is considered - migration does not add to the problem of global population growth since it is merely a displacement of peoples between countries.

In Chapter 5, I will develop some of my own figures for the Kaya Identity which allows us to decarbonize the economy out to 2050.  But before we consider those figures, in the coming two Chapters (to be published on 1 July and 1 August respectively) I will examine climate change and just why it is as dangerous to civilization as is often claimed.


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