Large demographic shifts will have many, mostly negative, effects on the quest for sustainable use of the planet.

If each nation state is viewed as a lifeboat, achieving sustainability will require a dispassionate, objective appraisal of the rate at which additional people can be taken aboard without sinking the lifeboat.

Each person in the lifeboat will have to relinquish some resources to accommodate each new arrival. In a country, this process means not only ceding one's personal share of resources but also the share of one's descendants in perpetuity.

When citizens realize the personal sacrifices necessary for even a modest rate of immigration, attitudes toward immigration should quickly change. Clearly, any rate of growth that results in an overall population gain is unsustainable.

As a consequence, immigration must be viewed in the context of sustainability ethics, which are based on indefinite use of the planet by humankind.

Actually, immigration is only a problem for a few, comparatively large, wealthy countries that attract immigrants like a magnet. Most countries on the planet are already exceeding "lifeboat" capacity, which immigrants recognize even if the leaders and a number of the citizens of the magnet countries do not. The major question of sustainability ethics is how this regrettable situation can be addressed before too many "lifeboats" begin sinking and exacerbate the problem.

ZERO NET IMMIGRATION
Do We Need Mass Immigration by Anthony Browne (2002) is a comprehensive evaluation of the economic, social and demographic effects of mass immigration into Britain -- which is experiencing the highest levels of net immigration in its history, quadrupling the rate of population growth. The population of Britain increased by 1.02 million between 1992 and 2000.

This growth rate is clearly unsustainable. Britain is importing poverty and concomitantly increasing social tensions (race riots have occurred), crime, and public health problems such as TB and HIV. The immigration, at present, is increasing social inequality in Britain because of a massive redistribution of wealth from those who compete with immigrants in the labor market to the wealthy people who employ the immigrants. This type of population flux is well documented in the United States and other countries that have a large number of immigrants (both legal and illegal).

Sustainable use of the planet will not be aided by a redistribution of wealth from poor to rich.

The Browne report addresses the way that false accusations of racism have hampered, perhaps even suppressed, legitimate debate about immigration. Lack of discussion has allowed widely believed immigration myths to persist.

Examples debunking some of the myths follow:
1. Britain does not have a declining population -- more babies are born each year than people die. Even with zero net immigration, the population will grow at a modest but significant rate from 59.8 million in 2000 to 60.3 million in 2020.
2. Britain does not have a declining workforce, but rather the fastest growing workforce in Europe. The Government Actuary Service estimates that, with zero net immigration, the workforce will grow by 1.2 million in 2020, from 36.89 million in 2000 to 38.127 million in 2020.
3. Britain is not suffering from a demographic time bomb that will place an unsupportable burden of retired people on the working population. The Government Actuary Service predicts that the number of children and pensioners per thousand people of working age will fall from 620 in 2000 to 583 in 2020.
4. Britain is not suffering from generalized labour shortages. According to the Labour Force Survey, there are 1.55 million unemployed people in the United Kingdom. Another 2.3 million are out of work but want to work - they do not look for work largely because they do not believe they will be able to secure jobs that pay well enough.
5. Immigration is no "fix" for an aging population, because immigrants grow old, too.
6. Immigration does boost gross domestic product (GDP); evidence does not indicate that immigration raises the level of the one measure that matters, GDP per capita.
7. Immigrants from developing countries, who make up the entire net immigration to the United Kingdom, are on average less well educated, suffer higher unemployment, claim more of most forms of benefits, make more demands on public services such as schools and hospitals, and almost certainly do not have funds to pay for these services.
8. The Browne report calls attention to official studies in the United States showing that average Mexican immigrants will consume, throughout their lifetime, $55,200 more in services each than they contribute in taxes.
9. Immigration is culturally enriching, but there are decreasing economies of scale. Doubling the immigration rate does not double the amount of cultural enrichment.
10. The poor are often the losers.
11. Those who benefit from immigration are those who employ immigrants (e.g., companies that exist on cheap labor).
12. The immigration-led rapid growth in population sharply increases the demand for new houses, which increases the pressure to build on greenbelt land.
13. Large-scale immigration without integration causes social fragmentation.
14. Immigration deprives most poor countries of their most educated and entrepreneurial individuals, often devastating health, educational, and other important systems. Immigration deprives developing countries of tax-paying and politically stabilizing middle classes.

This "must read" report concludes that a balanced, sustainable immigration policy for Britain is essential (and one might add, for the rest of the world). Since Britain is one of the world's most crowded countries, with a naturally growing population, the optimal level of net migration is zero or mildly negative.

This information-packed, well-reasoned report is essential reading for anyone interested in sustainable use of the planet.