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Seven billion - the no-nonsense guide to population growth


Vanessa Baird's new book, No-Nonsense Guide to World Population, is available from our online shop, or all good bookshops. This is the 28th title in our best-selling series.

On 31 October, according to the UN, world population tops seven billion.

It’s only 13 years ago that we hit six billion. So is population exploding? It certainly sounds like it, judging by many media reports.

But take a look at these graphics and you may see another picture emerging. Let’s start with the projections:

The top line assumes a high total fertility rate, or number of children a woman will have on average during her lifetime. This takes us to around 11 billion people by 2050.

The middle one (which is most commonly used) assumes a medium or ‘replacement’ fertility rate and takes us up to around nine billion.

The lowest assumes a below replacement fertility rate and takes us to around eight billion.

So, a lot depends on the fertility rate and its impact on family size:

In around 76 countries in the world, the current population is not even replacing itself. But is some low income countries, especially those in sub-Saharan Africa, the fertility rate has remained high, with women having around five children on average.

Let’s look at what happens to those three projections beyond 2050:

In a low fertility scenario world population peaks by 2050 and starts to decline. By 2100 we are back where we were 1998, with six billion people. This is what some population experts, including the UNFPA’s Ralph Hakkert, think will happen.

In a medium fertility scenario, where people carry on replacing themselves, the rate of population growth slows down until we gradually reach 10 billion by 2100.

In a high fertility world we hit 16 billion by 2100.

As we have seen over the past 50 years, the global trend is quite definitely towards smaller families. Once that trend begins, with people having fewer children or none at all, it is hard or even impossible to reverse – as policy in makers have found in countries with shrinking populations like Japan or Korea or parts of Europe.

We know that one of the strongest factors in determining family size is women’s education and empowerment.

Just look at what happens to fertility rates when women become more literate.

Some people who are concerned about global warming are saying that the priority has to be bringing down fertility rates in the countries where they are high. Currently 18 per of the world’s population lives in such countries low-income countries.

But the areas where population is growing fastest are those that emit least CO2 while countries where population is growing slowly or shrinking emit the most.

Look at this:

Cutting fertility in low income countries is unlikely to make much impact on global warming at all.

So should the gas-guzzling, high-consuming, high-income citizens of the rich world abstain from having babies, then?

They might, but still this does not deliver the cuts in CO2 we need – 80 per cent by 2050. Researchers at the National Centre for Atmospheric Research at Boulder Colorado have found that a reduction of around one billion in world population would deliver a cut of only around 15 per cent.

So, what do we need to do? Get off fossil fuels and switch to renewable energy. Stop wasting so much energy and food (up to half the world’s food gets wasted). Ban the type of financial speculation on food that is driving up food prices. Foster sustainable farming methods.

But above all remember that population is about people – not just numbers. More important than how many we are, is how we use and how we share the earth’s resources.

For more see the No-Nonsense Guide to World Population, by Vanessa Baird, published by New Internationalist.

Contents list:
1 Are too many people being born? 
2 A brief history of population
3 Being alive, staying alive – and growing old
4 A woman’s body
5 For richer, for poorer
6 On the move
7 Population and climate change
8 How can we feed nine billion
9 Wild things
10 Conclusion

Order now from the New Internationalist shop.

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