I agree that sustainability and population has some nexus and it can be derived while deriving sustainability index considering the criteria of sustainability as considered by Yale University as Environmental performance Indicators. The EPI ranking given for each country should be correlated with population of each of the nation. That Index will be more sensible and effective.

Such principle will be generally acceptable and workable. But some research must be conducted in this area.

the question has lot of significance and i recommend this question, too

First of all, it depends on your interpretation of what sustainability is. If what you mean by sustainability is the classic definition of intergenerational responsibility introduced by the Brundtland report, there are plenty of studies showing the unsustainability of current population trends, both in terms of numbers/population growth and behaviour/consumption of resources.

Undoubtedly it can, and must be inversely proportional to the population growth.

As noted above, part of the issue would be the measure of sustainability. Say, for example, you employ the ecological footprint. You could then examine the correlation between population growth and sustainability as measured by the ecological footprint.

It would be possible for the footprint to decrease while the population expanded. This is not to say that this is likely -- but it is possible. This would occur where the aggregate of consumption/pollution that comprise the ecological footprint fell at a more rapid rate than the population grows (it might also occur is consumption remained constant, but biocapacity increased, leading to a decline in the ecological footprint that was greater than the rise in population).

I would recommend reading several studies by Andrew K. Jorgenson on these issues.

Micheal - sure, this has happened in the US in the last 10 to 15 years, where the EF per capita went down by more than the population went up. Really, they just were exporting their polluting industries, so it's not quite as wonderful as it looks. But it does happen.

If we use Ecological Footprint as the measure of ecological impacts, then we still need a measure for the social and economic. But in principal, it should be workable.

I agree that sustainability and population has some nexus and it can be derived while deriving sustainability index considering the criteria of sustainability as considered by Yale University as Environmental performance Indicators. The EPI ranking given for each country should be correlated with population of each of the nation. That Index will be more sensible and effective.

Such principle will be generally acceptable and workable. But some research must be conducted in this area.

the question has lot of significance and i recommend this question, too

I agree with Dr K N Sheth

In my point of view sustainability is the quantitative measurement of a given system. I believe that sustainability must encompass the human-environmental system, that is, the biosphere. Therefore, sustainability can not be measured against population growth, as this is a component of the system. Sustainability can be measured by including growth as one of the indicators and not just as the main driver.

I agree with all the comments. We can see this with an "association" relationship but not a "causation" relationship. Whenever you see an association, yes - you can model sustainability "with" and "without" population growth and then a comparison can be made easily.

Alexander;

What units do you use to quantitatively assess Sustainability? I would use the time required within a community to meet needs, as if all needs were being met while considering the future impact on time due to loss of over-consumed resources, but that is very humanocentric. Is there a better unit of measurement that is sensitive to the ecosystem?

There must be a correlation between the two variables as indicated by Prof. Sheth. Yet, other variables must be equally considered to measure accurately, the rate of sustainability of resources in a country.

Following

Earth's carrying capacity is already well investigated, this document is one:

http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.491.5147&rep=rep1&type=pdf

This graph can be useful as well:

Sustainability seems to be more related to population density, not population in absolute numbers. Although there is no consensus about the subject, many authors agree that low density urbanization is related to more fuel consumption and car dependency, for instance. To know more about it look for research about urban sprawl. We should have more empirical research on sprawl impacts to produce new evidence on this relationship between population density and sustainability.

It is interesting to note that the 5 cities with the highest quality of life are all about 400,000 population, but they have no trend relating the area. The largest in area is about 20x the land area as the smallest. Quality of life appears, at first glance anyway, more tied to population (not too big or too small) than density.

Hi, we tried to answer this question via using historical statistics (for population, GDP, and the ecological footprint). My short answer is that most people misunderstand the "population bomb", which is not a bomb. These days overconsumption of the happy few and extreme inequality plays a much stronger role in unsustainable development, then (slowing) population increase in some developing countries. Full calculations and argumentation here:

Article The historical ecological footprint: From over-population to...