I Blame the Parents

Is it our increasing population that is really to blame for climate change?  Should we be focusing our efforts on reducing the birth rate rather than the emissions of those already alive?  This is a difficult one for me, with a young family of three, but I will remain objective and see where it leads – please bring me up short if I stray.

An expert in the field of forecasting long term trends, who happens to be an employee of a large oil company, suggested during a public debate that 40% of future increases in greenhouse gas emissions are expected to result from a growing population, with the other 60% from lifestyles.  On those rough figures, it would seem that the answer is a bit of both.

Logically, there wouldn’t be a problem if the human population was a lot lower – emissions would go down proportionally and more so with fewer people developed nations.  The problem would also largely go away if everyone adopted simpler, less destructive lifestyles.  A large population would still have a significant impact, though.

So what should we do?  I feel the need to look at a few numbers.

What would happen if we went to the extreme and banned all new births?  No one is suggesting we do – I’m just taking it to an extreme.  I’ll concentrate on the western world, in fact the UK, as I’ve got some numbers to help me.  Cautionary note – take these numbers as back of the fag packet calculations – I’m doing them to get a picture, nothing more.   They ought to be in the right ball-park.

According to the book “How Bad are Bananas?” by Mike Berners-Lee, the average child born now is expected to be responsible for 373 tonnes of carbon dioxide emissions in their lifetime.  According to UK government projections, there are expected to be 1,100 births per 1,000 women from 2014 to 2030 [no, must have misinterpreted the ONS site – less than half that – thanks to Stewart for pointing out in comments below – other figures below have been corrected accordingly].  Over that period, there will be about 67 million people in the UK on average, so about 33.5 million women.  So about 15 million births.  By my rough calculations they would be responsible for about 4 billion tonnes of CO2 over their lifetimes, of which 1.3 billion tonnes will be emitted by the end of 2030.  That’s of a total of 10.8 billion tonnes for which the UK is expected to be responsible over the same period.

So we could reduce our total emissions by 13% if we stopped all births over that period.  Of course we wouldn’t stop all births, that would be crazy.Emissions per year kids from 2014

So how about reducing the birth rate so the average number of children per family was 2?  It’s only slightly over 2 at the moment, so that would have very little effect.  Roughly speaking, reducing the number of children to one per family would save about 7% of UK emissions.

These numbers all assume that the UK will decarbonise the energy sector by 80% by 2050, according to its international agreements.  They also assume that children are as responsible for as much carbon dioxide as adults.

So, from a carbon emissions standpoint, it is worth trying to reduce the birth rate.

But it certainly wouldn’t solve climate change.  And it would reduce emissions anywhere near quickly enough.  The only way to do that is to stop using as much fuel and energy now, by our lifestyle choices.

John Bell,

Ordinary bloke

Some Numbers – A 4⁰C World

In my last post I said I’d look into information available quantifying the effects of the level of climate change currently expected.  I have to admit that I’ve spent a very frustrating morning trying to find facts and figures about the effects and have not managed to find a great deal, particularly relating to the effects of the 4 to 6 ⁰C increases that are forecast on current trends (of change and our response to date and planned).

Anyone reading who has another or better source of up to date facts and figures about what we are letting ourselves in for, please do comment at the bottom of this post.

Generally what I’ve found is that when looking at the higher end of the forecast increases in temperatures, commentary in the scientific papers falls back on statements to the effect of “it will be really bad” and comparing with the coldest temperatures during the last ice age (5-6 ⁰C lower than current temperatures).

I think the lack of quantification available is genuine.  But I think some numbers would be better than none:

 “Uncertainty is an argument for a more, not less, demanding goal [on reducing greenhouse gas emissions], because of the size of the adverse climate-change impacts in the worst-case scenarios.” – Stern, 2006

And taking that a step further, lack of figures on the impacts is an argument for a more, not less, demanding goal, because the figures that we do have, particularly for lower increases, are bad enough.

Anyway, on to what I have managed to unearth.

My main source is a paper published in January 2011 by the Royal Society.  I’ll put links to the sources directly in the text below.  To start, a 4 ⁰ C increase is estimated to be reached during 2070s.

Looking at water, it looks as though dry regions are to get dryer and wet regions are to get wetter.  I found it difficult to interpret the graphs, but it appears to show a 30-70% decrease in the water available per capita, dependent on population growth and temperature change (the latter dominates in a 4 ⁰C world).  The regions under the greatest water stress at the moment are the US, Mediterranean Europe, India and China, plus parts of Africa – and these are the areas that are expected to feel the brunt of increases in water stress in the coming decades.  This is leading to increases in grain prices as water is used directly rather than for agriculture.

Looking at monetised costs, in Africa alone in 2030 for adapting to climate change are estimated at $60 billion per annum.  This still leaves residual effects that cannot be avoided.

Costs for global sea-level rises for a 4 ⁰C world are expected to reach $37-407bn per annum (I’ve adjusted to show present value), with the range depending on whether 4 ⁰C leads to 50 cm or 2 m of rises, which in turn depends on the unknown extent of the melting of the Greenland ice sheet in those conditions.

The Stern Report of 2006 costs of mitigating climate change are -2% to +5% of GDP (the lower part of the range relating to more prompt and efficient mitigation action), with an average of 1% of GDP.  Global consumption would decrease by 20% otherwise.  Then the net benefits of one year’s action to mitigate climate change would be of the order of $2.5 trillion.  So we should do so, you would think?

The UK parliament is currently discussing the Energy Bill.  It falls short in that it doesn’t commit to a target on reducing greenhouse gas emissions, and so I urge you to take action to promote amendments to the bill to introduce an end target and interim targets.  In developed nations, we need to largely decarbonise by 2030 for 37% chance of not exceeding 2 ⁰C (assuming developing nations peak their emissions by around 2025), according to the Royal Society.

The proposed changes to the bill not only give us a chance of mitigating climate change, they also make sound economic sense in the medium term.  It is estimated that there would be a £23bn saving in the UK if we went for de-carbonisation rather than for emerging fossil fuel deposits.  Gas prices (not renewables) were responsible for 62% of the increase in energy prices since 2004.

Again, if anyone reading has a different or better source of information about the quantification of the effects of a changing climate, then please do share by commenting below.

John Bell,

Ordinary bloke