population, size matters

This graph of world population growth probably doesn’t provide the scare factor it once did. We see it too often nowadays. Still, the population trend of the last 200 years can’t be ignored when thinking about the sort of world the next generation will inherit, the world as it will be in just 42 years.

The 9.2 billion projection for 2050 is the “medium variant” from the UN WPP2006 report (see “notes” below for links). The 7.8 number is “low variant” which assumes a fertility rate of 0.5 children/woman less than the medium scenario.

The editorial that prompted the previous post offers this way to think of the population growth the world is experiencing:

The annual increase in population of about 79 million means that every week an extra 1.5 million people need food and somewhere to live. This amounts to a huge new city each week, somewhere, which destroys wildlife habitats and augments world fossil fuel consumption.

This incredible growth also means we can not begin to solve the problem of extreme poverty let alone those built on its back — terrorism and environmental degradation — without getting a handle on population growth.

The current world population of 6.7 billion is double that of 40 years ago. We are now poised to add 2.5 billion more to that number in the next 40 years — even though about half of the people alive today live in what an American (or European or Japanese) can only think of as abject poverty, that is, living on less than $2.50/day which produces some mix (and for some all) of the following conditions:

• without adequate safe water for cooking, washing, and drinking
• without adequate sanitation
• without adequate nutrition
• without adequate medical and educational resources
• without adequate access to capital to improve their conditions

Here’s another way to look at world population growth:

The “medium variant” assumes fertility on average will continue to decline, mortality will on average improve, and we will gradually improve the treatment for HIV/AIDS, in short, current trends will continue. The “low variant” assumes on average a fertility rate of 0.5 less than the medium.

Numbers of special interest:

• 2.5, the difference in billions between current and projected population in the medium “business as usual” scenario. This is about the current population size of India and China combined. It took a couple hundred thousand years to get to the first 2.5 billion, but in the next 42 years we will add that same amount.
• 1.1, the difference in billions between current and projected population in the “low” scenario, about the current population size of India.
• 1.4, the difference in billions between the medium and low variants of the 2050 population projections (9.2 – 7.8), about the current population size of China.

In either scenario in the next 42 years we are going to increase world population by at least the number of people now living in India, and in the medium variant, the business as usual scenario, we’ll add another China as well.

where will the additional people go?

The population increase is not evenly distributed. Here we’ll look at three country groups:

The most developed — Europe (including Eastern Europe and Russia), Canada, the USA, Australia, New Zealand and Japan.

The least developed, the 50 poorest countries — 34 in Africa, 10 in Asia, 5 in Oceania, and Haiti in the Carribbean. Among them are names that frequently occur in the news: Afghanistan, Angola, Bangladesh, Cambodia, Chad, Congo, Eritrea, Ethiopia, Haiti, Liberia, Myanmar, Rwanda, Somalia, Sudan, Uganda, and Yemen.

All the rest, notably including India, China, Indonesia, Pakistan, the Korea’s, Vietnam, Thailand, all of Latin American as well as most of the Middle East and Northern Africa.

The first part of the answer to where is the population going to increase is “not in the rich world.”

The most developed countries experience a population decline of 0.1 billion in the low scenairo and show no change overall in the medium. The notable exception is the USA which increases by 0.04 (more than one California) in the low variant and 0.1 billion (three Californias) in the medium.

In both scenarios the least developed nations (the least stable, the most voilatile) about double in size, going from significantly fewer people than the most developed countries to significantly more. The increase here is between 0.7 to 0.9 billion.

The population change between now and 2050 in the “other” countries is between 0.5 and 1.5 billion.

choice

Using the medium and low variants as a basis, our choice is a stark one. In just 42 years our currently overcrowded, ecologically stressed world that’s having a hard time finding enough water, food, energy, medical care, and capital to go around, we either add another India or another India and another China — 1.1 billion more or 2.5 billion more. How do we compassionately achieve the lower end of the range?

Part of the answer lies in empowering women and providing family planning information and contraception services to everyone as discussed here and here. Another part is getting religious leaders to help which is addressed in that second link and also here.

In Iran religious leaders encouraged a reduction in the birthrate through education and contraception and in a few years a very high birthrate was brought down to a reasonable level then to the replacement rate. In the Philippines where the Catholic church holds sway religious leaders fundamentally oppose any use of contraception even though, quite notably, business leaders understand and approve of family planning and the use of contraceptives. The Philippines is struggling to cope with its high population growth, increasing wealth disparity, and increasing numbers of poor people.

Contrary to the much bandied about assumption that fertility rates only come down as the standard of living rises, proactive programs to teach and encourage family planning and the availability of contraceptives have a real impact aside from changes in income.

direction

The economist Jeffery Sachs provides an intelligent, informed way forward in The of Poverty: Economic Possibilities of Our Time. Sachs, an advisor to a number of countries since the late 1980’s (including Bolivia, Poland, Russia, China, & India), has led many countries in the transition from communism to market economies.

notes

Data for population prior to 1950 is from this paper by the Optimum Population Trust. The data from 1950 to the present and projected to 2050 comes from the United Nations, Department of Economic and Social Affairs Population Division, World Population Prospects: The 2006 Revision (WPP2006). WPP2006 presents 11 different projections based on differing assumptions about fertility, mortality, and international migration. (See here for the details.) The one most often cited is the medium variant used in the diagram above which assumes,

Total fertility in all countries is assumed to converge eventually toward a level of 1.85 children per woman. However, not all countries reach this level during the projection period, that is, by 2045-2050. Projection procedures differ slightly depending on whether a country had a total fertility above or below 1.85 children per woman in 2000-2005.