Population Growth and Climate Change

Today I read an interesting article in the Bulletin of Atomic Scientists, addressing a way to slow climate change – reproductive rights.  A neglected climate strategy: Empower women, slow population growth

Ms. Mazur presents an interesting case and analysis, one that I largely agree with.  However, I would like to see some more solid numbers behind this.  Even ballpark figures could give us an idea of comparative costs and benefits.  For example, earning a college degree typically results in almost double the lifetime income earned.  ($1.2 million to $2.1 million). 

If smaller families equates to greater investment in children (PDF), then having smaller families will lead to a more educated population, and a more educated population tends to lead to fewer children.  (This relationship is not necessarily causal, but countries with higher levels of education tend to have smaller families.  It could be because there is less need for extra hands “on the farm” per say, and is probably somewhat related.) 

I would also have liked to see the cost of attaining the reducing in unwanted pregnancies (lets assume it costs $5 / year, and at 200 million pregnancies, that would be $1 billion per year), then compare it to the benefits stated in the article: higher levels of education for the parent, reduced death from childbirth, lower risk of STD’s (assuming condom use or abstinence), lower levels of consumption and hence lower GHG emissions. 

Now, since the focus is on climate change, I’ll look at some numbers for carbon costs.  Today, the European Markets were trading at ~14 euros per ton (~$20/ton).  The EIA (~1/2 way down the page) has for Africa listed current emissions of 1 metric ton per capita in 2006, staying flat to 2030.  China, by comparison is at 4.6 in 2006, rising to 8.0 by 2030.   Taking this 1 metric ton, and comparing it with the carbon markets, a reduction of 200 million pregnancies would cost $4 billion, or 4 times the cost of reducing unwanted pregnancies.  This number swells if you think of future projections.  Namely, if these reductions were all assumed for China alone in 2030, it would be $32 billion assuming carbon prices remained at their current levels (not at all likely), or about 32 times the cost.

Lets put this into perspective.  A quick look at a carbon offset aggregator (Ecobusinesslinks), shows an average price of around $15.00 per ton through a variety of measures (some such as carbon offsets through reforestation may not deliver, as carbon sinks need to remain in place for ~70 years to get their claimed value).  This generates around the same value as the market-based value above (or ~4 – 32 times the cost of preventing unwanted population growth).  Similarly, a 277 kw system is projected to save 11.7 million tons of emissions over 25 years.  Taking about $1 per watt, this installation would cost $300,000.  Over the 25 years, it comes out to about $39 per ton of emissions reductions (or twice what carbon is currently trading for on the markets).

By doing this back of the envelope calculations, I believe I have made the case that Ms. Mazur’s argument does hold up when some rough numbers are thrown in.  To address climate change, we should look at all solutions.  Addressing population growth is one way to do this, that may also have a multitude of other benefits, not strictly related to climate change alone.

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