By Mark Lynas, author of The God Species: How the Planet Can Survive the Age of Humans. Originally published at "High Tides" weblogs.
The Royal Society - Britain's premier scientific institution - has just released a major report called People and the Planet, arguing that per capital resource consumption in the richest parts of the world needs to come down dramatically if the poorest 1.3 billion are to be lifted out of extreme poverty whilst protecting the Earth's environment from irreparable harm. (Do join Leo Hickman's debate on the Guardian site here, and my thanks to him for prompting this piece.)

I wouldn't argue with most of the data underpinning this report, but I do have problems with some of the assumptions. The first is that population growth is necessarily a bad thing, and that there is therefore a pressing need to reduce the rate of growth in developing countries. The report states early on:

"At a time when so many people remain impoverished and natural resources are becoming increasingly scarce, continued population growth is cause for concern."

What it fails to acknowledge however is that population growth is correlated with economic growth - and therefore if developing countries are to continue to escape from poverty then reducing their rate of population growth should not be the initial priority. In a recent blogpost the World Bank's Wolfgang Fengler starts by reminding us:

Africa's population is rising rapidly and will most likely double its population by 2050. Depending on the source of data, Africa will soon pass 1 billion people (and it may already have) and could reach up to 2 billion people by 2050 [ I am using the UN's 2009 World Population Prospects, which projects Africa to exceed 1.7 billion by 2050 based on sharply declining fertility rates]. This makes it the fastest growing continent and Africa's rapid growth will also shift the global population balance.

Sounds scary. But what no-one mentions is that in terms of population density Western Europe is far more over-populated than Africa:

If we look at Western Europe - where I come from - there are on average 170 people living on each square km. In Sub-Saharan Africa there are only 70 today. This gap will narrow in the next decades but even by 2050, Western Europe is expected to be more densely populated than Africa.

He then concludes:

...population growth and urbanization go together, and economic development is closely correlated with urbanization. Rich countries are urban countries. No country has ever reached high income levels with low urbanization. And this is critical for achieving sustained growth because large urban centers allow for innovation and increase economies of scale. Companies can produce goods in larger numbers and more cheaply, serving a larger number of low-income customers.

Population growth may therefore put us on the edge of a "golden age of development" for Africa - hardly the message from the gloomy Royal Society report. As the excellent book Emerging Africa, by Steven Radelet, shows, seventeen sub-Saharan African countries have seen sustained economic growth since 1995, vastly improving their prospects and - I suspect - further reducing fertility rates in the process.

Whilst using a lot of dark language about increasing numbers of humans globally, the report nowhere acknowledges that the current median level of total worldwide fertility has fallen dramatically from 5.6 in the 1970s to only 2.4 today. In other words we are already close to natural replacement levels in terms of total fertility - the reason that the absolute population will continue to grow to 9 billion or more is that more children are living long enough have their own children. To my mind a reduction in infant mortality and an increase in life expectancy are self-evidently good and desirable - and their impact on world population levels should be celebrated, not bemoaned.

Secondly, the report seems to be largely predicated on a neo-Malthusian version of economics, where resource use is a zero-sum game, and therefore the rich need to get poorer if there is to be any increase in comsumption for the poorest. It states:

Human impact on the Earth raises serious concerns, and in the richest parts of the world per capita material consumption is far above the level that can be sustained for everyone in a population of 7 billion or more. This is in stark contrast to the world's 1.3 billion poorest people, who need to consume more in order to be raised out of extreme poverty.

Therefore:

The most developed and the emerging economies must stabilise and then reduce material consumption levels...

This redistributive model has been shown in the real world to be completely wrong: China, India and now many African countries have seen rapid and sustained economic growth (and the concurrent lifting out of poverty of hundreds of millions of people) not because we have had to reduce our own wealth and consumption in an absolute sense, but through trade and other globalisation-related liberalisation benefiting both parties (and the poorest most).

Moreover, a dramatic decline in inequality is already actually happening, because the richest countries are either not growing now (due to the post-2008 economic crisis) or are growing very slowly, whilst the emerging economies and even many sub-Saharan African countries are growing at 5% or more per year. The big Malthusian error - which was repeated by the Limits to Growth approach of the 1970s, and many times afterwards - was to see 'natural resources' as some kind of absolutely-limited cake which would have to be shared equally if all were to exit from poverty.

In actual fact the stock of natural resources (natural capital) change both both because of consumption patterns and technology. Take fisheries - it is often assumed that because many are over-exploited at the moment then there will never be enough fish for everyone's wants to be satisfied. However, as a scientific report only last week showed, if fisheries and aquaculture are properly managed there can be at least the same levels of per capita fish consumption by 2050 as today (for a 9.5 billion population). There is no reason to assume collapse is inevitable.

Similarly for energy - if we deploy sufficient clean energy resources (renewables, nuclear and gas with carbon capture) there is no fundamental limit on human potential energy consumption. Energy is essential for water supply (increasingly with desalination), agricultural production, urbanisation and so on - and here the Limits to Growth assumptions are both anti-development and nonsensical.

To conclude: I would love to see a much more positive approach from scientists on these issues, one acknowledging human development as a much more positive prospect, and treating environmental resources not as a fixed quantity but as a dynamic part of a rapidly-changing (and in many ways improving) world. This does not mean denying biophysical limits ('planetary boundaries') insofar as they can be scientifically determined, but it does mean taking a radically-different, and much more human-centred, approach to tackling them.