Not long ago I spent some time on the Indian subcontinent and one of my abiding memories is of travelling from the far-flung Nepali town of Jumla, home to some of the thinnest people on the planet, to the airport lounge at Delhi, where the bulk of passengers were Westerners, notably Americans, and where the human race seemed to have undergone a vast distension in size – an entire evolutionary cycle in the blink of an eye.

At the time it struck me as a metaphor for the economic relationship between North and South – one part of the planet growing fat on the food shortages of the other – but I have since realised it’s a metaphor with many interpretations.

Obesity

For the first time in history, it was reported this summer, there are now more overweight people in the world (more than a billion) than malnourished (around 800 million). But there are also many more people, fat and thin alike.

Back in August, the Office of National Statistics disclosed that the UK had broken through the 60 million population barrier (in 2005), while the US was due to reach 300 million by October 2006. Both are markers of a process that sees over 70 million people being added to the global population each year, with growth forecast at 40 per cent by 2050, taking us from 6.5 to 9.1 billion – another 2.6 billion people. But will they be fat people or thin people and does it matter? I think it does.

The taboo subject

Trying to discuss human population growth these days is not unlike placing your head on a stand at a coconut shy. The Right will accuse you of authoritarianism and permissiveness, the Left of being racist, fascistic or neo-Malthusian.

The recent upsurge in migration as a key factor in population growth in developed countries has added a further inflammatory ingredient. To their eternal discredit, environmental groups, fearful of such a witches’ brew, have fled the field, camouflaging their retreat in a blizzard of rationalisations.

Yet according to the head of one leading environmental organisation, population is the subject that attracts the most questions at meetings round the country. In fact, if you’re looking for issues that best demonstrate the chasm between what ordinary people think – not least because they experience its realities daily – and what civil society leaders deem it politic to mention in public, population would undoubtedly come high up the list.

What explains this? One much-cited factor is political correctness (PC), a phrase  the Right loves, the Left hates and most neutrals acknowledge exists but have trouble defining.

In this case, PC may be shorthand for the deliberate substitution of one agenda – reproductive health – for another, more overtly concerned with human numbers. This gathered impetus after the Cairo population conference in 1994 and one result has been the systematic exclusion of the numbers dimension from permissible civil society discourse – and, to a degree, the ostracising and blackballing of its proponents.

Population Concern

One of the most vivid expressions of this was the decision by the long-established NGO Population Concern to rebrand itself Interact Worldwide in 2003 – a move which the group saw as its only means of survival but which would have no doubt fascinated 1984 author George Orwell, deviser of Newspeak.

There was a rationale to this, of course. Concern with numbers had become (wrongly) associated with a coercive approach – chiefly Mrs Gandhi’s sterilisation polices in India and China’s (continuing) one-child policy.

Too much attention had focused on developing countries as the chief locus of population growth – the ‘teeming millions’ thesis. More significantly, environmentalists in particular had absorbed the message that numbers are not the only factor: how you live is also important. In terms of global environmental impact, one fat person – metaphorically speaking – can do as much damage as many thin ones.

America's footprint

Over the past decade or so, the rapidly developing methodology of ecological footprinting has helped elaborate such calculations. The latest Living Planet report, for example, tells us not only that in 2001 humanity as a whole overshot the Earth’s annual biological capacity by 20 per cent but that one American has 12 times the overall global impact of one Indian.

So, although India, with 1.1 billion people, is conventionally thought of as being ‘overpopulated’ while the US, with 300 million, is not, the reality is very different. On a like-for-like comparison with India, for example, the US population is 12 times 300 million – or 3.6 billion. In other words, the US as a whole does three times more global environmental damage than India as a whole.

Do the sums for the two countries’ per capita greenhouse gas emissions – and therefore impact on the earth’s atmosphere alone, as opposed to the entirety of the global ecosystem – and the results are even more extreme, since an American emits roughly 20 times more carbon than an Indian.

Environmental groups have grasped this approach but have chosen to interpret it as meaning that numbers no longer matter – that greening our lifestyles and our technologies is the key. For some, this approach is no doubt genuine – in the sense in which Thomas Kuhn talked about paradigm shifts, they no longer ‘see’ the population growth lurking behind virtually every aspect of environmental crisis.

Green groups ignoring population

For others, I suspect, it is a kind of wilful blindness, born of realpolitik plus a desire not to alienate members, upset fellow progressives and get their heads knocked off the coconut stand. But the verdict of green historians will surely be that it’s a betrayal of future generations.

How can groups such as Friends of the Earth and the Campaign to Protect Rural England work to defend green space from development and not recognise the crucial importance of human numbers – the numbers of those wanting housing, offices, shops, schools, leisure facilities?

The truth is that greener lifestyles can make a difference but that zero-impact living, for the foreseeable future, is a chimera and that human numbers do matter – hugely. Footprinting studies by Andrew Ferguson at the Optimum Population Trust suggest that if a world of six billion lived a ‘modest’ western European lifestyle based entirely on renewable energy, it would still need, to support it, another 1.8 planets – a figure that can only increase as populations rise and their needs, wants and aspirations multiply.

The UK, with a projected increase of 10 million – roughly a sixth – over the next half century, is in the front line of this process – a small, over-urbanised,  overcrowded country, its quality of life visibly plummeting, no longer capable of surviving on its own resources yet jamming hundreds of thousands more people in every year.

Many of these are ‘thin’ people – from Eastern Europe, say, or the developing world – whom we turn fairly quickly into fattish ones, as they become Western urban consumers, so the story is a speeded-up version of what’s happening on the planet at large. But the lesson in both cases is the same. Fat people, ecologically speaking, may be very bad news, thinnish people are better; but whether we’re fat, thin or medium-sized, there’s only so many of us the planet can take.

David Nicholson-Lord is a research associate with the Optimum Population Trust (www.optimumpopulation.org) and former environment editor of the Independent on Sunday.

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This article first appeared in the Ecologist October 2006